WorldWideScience

Sample records for experiment asdex upgrade

  1. ECRH experiments in ASDEX Upgrade

    International Nuclear Information System (INIS)

    Leuterer, F.; Guenter, S.; Hobirk, J.; Kirov, K.; Ryter, F.; Wolf, R.; Zohm, H.; Gantenbein, G.

    2001-01-01

    In ASDEX Upgrade ECRH and ECCD with a power of up to 2 MW has been used. With counter ECCD in discharges with an internal transport barrier we achieved an electron temperature of ≅13 keV. In low density ohmic plasmas we obtained an rf driven current of ≅80% both in co- and counter directions. Neoclassical tearing modes have been completly stabilised by driving a current on the resonant q-surface. Electron heat transport has been studied in standard L- and H-mode plasmas and can be described by a dependence on a critical electron temperature gradient

  2. Modelling and experiments on NTM stabilisation at ASDEX upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Urso, Laura

    2009-07-27

    In the next fusion device ITER the so-called neoclassical tearing modes (NTMs) are foreseen as being extremely detrimental to plasma confinement. This type of resistive instability is related to the presence in the plasma of magnetic islands. These are experimentally controlled with local electron cyclotron current drive (ECCD) and the island width decay during NTM stabilisation is modelled using the so-called Modified Rutherford equation. In this thesis, a modelling of the Modified Rutherford equation is carried out and simulations of the island width decay are compared with the experimentally observed ones in order to fit the two free machine-independent parameters present in the equation. A systematic study on a database of NTM stabilisation discharges from ASDEX Upgrade and JT-60U is done within the context of a multi-machine benchmark for extrapolating the ECCD power requirements for ITER. The experimental measurements in both devices are discussed by means of consistency checks and sensitivity analysis and used to evaluate the two fitting parameters present in the Modified Rutherford equation. The influence of the asymmetry of the magnetic island on stabilisation is for the first time included in the model and the effect of ECCD on the marginal island after which the mode naturally decays is quantified. The effect of radial misalignment and over-stabilisation during the experiment are found to be the key quantities affecting the NTM stabilisation. As a main result of this thesis, the extrapolation to ITER of the NTM stabilisation results from ASDEX Upgrade and JT-60U shows that 10MW of ECCD power are enough to stabilise large NTMs as long as the O-point of the island and the ECCD beam are perfectly aligned. In fact, the high ratio between the island size at saturation and the deposition width of the ECCD beam foreseen for ITER is found to imply a maximum allowable radial misalignment of 2-3 cm and little difference in terms of gained performance between

  3. Modelling and experiments on NTM stabilisation at ASDEX upgrade

    International Nuclear Information System (INIS)

    Urso, Laura

    2009-01-01

    In the next fusion device ITER the so-called neoclassical tearing modes (NTMs) are foreseen as being extremely detrimental to plasma confinement. This type of resistive instability is related to the presence in the plasma of magnetic islands. These are experimentally controlled with local electron cyclotron current drive (ECCD) and the island width decay during NTM stabilisation is modelled using the so-called Modified Rutherford equation. In this thesis, a modelling of the Modified Rutherford equation is carried out and simulations of the island width decay are compared with the experimentally observed ones in order to fit the two free machine-independent parameters present in the equation. A systematic study on a database of NTM stabilisation discharges from ASDEX Upgrade and JT-60U is done within the context of a multi-machine benchmark for extrapolating the ECCD power requirements for ITER. The experimental measurements in both devices are discussed by means of consistency checks and sensitivity analysis and used to evaluate the two fitting parameters present in the Modified Rutherford equation. The influence of the asymmetry of the magnetic island on stabilisation is for the first time included in the model and the effect of ECCD on the marginal island after which the mode naturally decays is quantified. The effect of radial misalignment and over-stabilisation during the experiment are found to be the key quantities affecting the NTM stabilisation. As a main result of this thesis, the extrapolation to ITER of the NTM stabilisation results from ASDEX Upgrade and JT-60U shows that 10MW of ECCD power are enough to stabilise large NTMs as long as the O-point of the island and the ECCD beam are perfectly aligned. In fact, the high ratio between the island size at saturation and the deposition width of the ECCD beam foreseen for ITER is found to imply a maximum allowable radial misalignment of 2-3 cm and little difference in terms of gained performance between

  4. The ASDEX Upgrade ICRF system: Operational experience and developments

    International Nuclear Information System (INIS)

    Faugel, H.; Angene, P.; Becker, W.; Braun, F.; Bobkov, Vl.V.; Eckert, B.; Fischer, F.; Hartmann, D.A.; Heilmaier, G.; Kneidl, J.; Noterdaeme, J.-M.; Siegl, G.; Wuersching, E.

    2005-01-01

    The ICRF system at the ASDEX Upgrade tokamak is in operation since May 1992. Following some modifications of which the major one was the installation of 3 dB couplers it has become a reliable additional heating system. The maximum power coupled into the plasma has been raised up to 7.2 MW (90% of the installed RF power) for short pulses and up to 6.2 MW for pulses several second long with energy of up to 29 MJ. A power of 5 MW is delivered on a regular basis to replace two NBI sources

  5. Nitrogen implantation in tungsten and migration in the fusion experiment ASDEX upgrade

    International Nuclear Information System (INIS)

    Meisl, Gerd Korbinian

    2015-01-01

    The implantation of nitrogen ions into tungsten was studied in laboratory experiments to understand the interaction of nitrogen containing fusion plasmas with tungsten walls. The resulting model of W-N interaction was tested by experiments in the tokamak ASDEX Upgrade. Using the measurements from these experiments as boundary condition, nitrogen transport and re-distribution in the plasma were modeled by self-consistent WallDYN-DIVIMP simulations.

  6. Experiences with tungsten coatings in high heat flux tests and under plasma load in ASDEX Upgrade

    International Nuclear Information System (INIS)

    Herrmann, A; Greuner, H; Fuchs, J C; Marne, P de; Neu, R

    2009-01-01

    ASDEX Upgrade was operated with about 6400 s plasma discharge during the scientific program in 2007/2008 exploring tungsten as a first wall material in tokamaks. In the first phase, the heating power was restricted to 10 MW. It was increased to 15 MW in the second phase. During this operational period, a delamination of the 200 μm W-VPS coating happened at 2 out of 128 tiles of the outer divertor and an unscheduled opening was required. In the third phase, ASDEX Upgrade was operated with partly predamaged tiles and up to 15 MW heating power. The target load was actively controlled by N 2 -seeding. This paper presents the screening test of target tiles in the high heat flux test facility GLADIS, experiences with operation and detected damages of the outer divertor as well as the heat load to the outer divertor and the reasons for the toroidal asymmetry of the divertor load.

  7. q=1 advanced tokamak experiments in JET and comparison with ASDEX Upgrade

    International Nuclear Information System (INIS)

    Joffrin, E.; Wolf, R.; Alper, B.

    2002-01-01

    The ASDEX Upgrade advanced tokamak scenario with central q close to 1 has been reproduced on JET. For almost identical q profiles, the comparative analysis does show similar features like the fishbone activity and the current profile evolution. In JET, transport analyses indicates that an internal transport barrier (ITB) has been produced. Gradient length criterions based on the ion temperature gradient turbulence stabilization are used to characterize the ITBs in both devices. The trigger of ITBs is associated with rational surfaces in both devices although the underlying physics for this triggering seems different. This experiment has the prospect to get closer to identity experiments between the two tokamaks. (author)

  8. Time accuracy requirements for fusion experiments: A case study at ASDEX Upgrade

    International Nuclear Information System (INIS)

    Raupp, Gerhard; Behler, Karl; Eixenberger, Horst; Fitzek, Michael; Kollotzek, Horst; Lohs, Andreas; Lueddecke, Klaus; Mueller, Peter; Merkel, Roland; Neu, Gregor; Schacht, Joerg; Schramm, Gerold; Treutterer, Wolfgang; Zasche, Dieter; Zehetbauer, Thomas

    2010-01-01

    To manage and operate a fusion device and measure meaningful data an accurate and stable time is needed. As a benchmark, we suggest to consider time accuracy as sufficient if it is better than typical data errors or process timescales. This allows to distinguish application domains and chose appropriate time distribution methods. For ASDEX Upgrade a standard NTP method provides Unix time for project and operation management tasks, and a dedicated time system generates and distributes a precise experiment time for physics applications. Applying the benchmark to ASDEX Upgrade shows that physics measurements tagged with experiment time meet the requirements, while correlation of NTP tagged operation data with physics data tagged with experiment time remains problematic. Closer coupling of the two initially free running time systems with daily re-sets was an efficient and satisfactory improvement. For ultimate accuracy and seamless integration, however, continuous adjustment of the experiment time clock frequency to NTP is needed, within frequency variation limits given by the benchmark.

  9. Multiprocessor systems for real-time data acquisition on the Asdex upgrade and future plasma experiments

    International Nuclear Information System (INIS)

    Zilker, M.; Hallatschek, K.; Heimann, P.; Hertweck, F.

    1999-01-01

    In this paper we present our transputer-based multitop multiprocessor systems for data acquisition, which are currently used on the Asdex upgrade experiment. The bandwidth of these systems goes from low-speed like the calorimetry diagnostic up to highspeed and large data volume systems like the soft-X-ray and Mirnov diagnostics, which collect several hundreds of megabytes of data during a plasma discharge of ∼8 s. Further, we present the multitop-MX, a newly developed system based on transputers and powerPCs, which provides real-time facilities for analysing the acquired data, to generate necessary information for the dynamic adaptation of sample rates, and to deliver triggers when certain events in the plasma are detected. The algorithm running on the powerPCs performs a wavelet like time-frequency transform. In the last part we give an outlook how to build the next generation of data acquisition systems to be used on the future plasma experiments W7-X and ITER, but also on Asdex upgrade. The hardware of these new distributed systems should be mainly based on established industry standards like the VME-bus, PCI-bus and FiberChannel, but also emerging technologies like SCI (scalable coherent interconnect) should be considered. The systems software should be well designed with object oriented methods to simplify the maintenance process and to enable further expansions and adaptations to new problems in an easy way. (orig.)

  10. Overview of ASDEX Upgrade results

    NARCIS (Netherlands)

    Stroth, U.; Adamek, J.; Aho-Mantila, L.; Akaslompolo, S.; Amdor, C.; Angioni, C.; Balden, M.; Bardin, S.; L. Barrera Orte,; Behler, K.; Belonohy, E.; Bergmann, A.; Bernert, M.; Bilato, R.; Birkenmeier, G.; Bobkov, V.; Boom, J.; Bottereau, C.; Bottino, A.; Braun, F.; Brezinsek, S.; Brochard, T.; M. Brüdgam,; Buhler, A.; Burckhart, A.; Casson, F. J.; Chankin, A.; Chapman, I.; Clairet, F.; Classen, I.G.J.; Coenen, J. W.; Conway, G. D.; Coster, D. P.; Curran, D.; da Silva, F.; P. de Marné,; D' Inca, R.; Douai, D.; Drube, R.; Dunne, M.; Dux, R.; Eich, T.; Eixenberger, H.; Endstrasser, N.; Engelhardt, K.; Esposito, B.; Fable, E.; Fischer, R.; H. Fünfgelder,; Fuchs, J. C.; K. Gál,; M. García Muñoz,; Geiger, B.; Giannone, L.; T. Görler,; da Graca, S.; Greuner, H.; Gruber, O.; Gude, A.; Guimarais, L.; S. Günter,; Haas, G.; Hakola, A. H.; Hangan, D.; Happel, T.; T. Härtl,; Hauff, T.; Heinemann, B.; Herrmann, A.; Hobirk, J.; H. Höhnle,; M. Hölzl,; Hopf, C.; Houben, A.; Igochine, V.; Ionita, C.; Janzer, A.; Jenko, F.; Kantor, M.; C.-P. Käsemann,; Kallenbach, A.; S. Kálvin,; Kantor, M.; Kappatou, A.; Kardaun, O.; Kasparek, W.; Kaufmann, M.; Kirk, A.; H.-J. Klingshirn,; Kocan, M.; Kocsis, G.; Konz, C.; Koslowski, R.; Krieger, K.; Kubic, M.; Kurki-Suonio, T.; Kurzan, B.; Lackner, K.; Lang, P. T.; Lauber, P.; Laux, M.; Lazaros, A.; Leipold, F.; Leuterer, F.; Lindig, S.; Lisgo, S.; Lohs, A.; Lunt, T.; Maier, H.; Makkonen, T.; Mank, K.; M.-E. Manso,; Maraschek, M.; Mayer, M.; McCarthy, P. J.; McDermott, R.; Mehlmann, F.; Meister, H.; Menchero, L.; Meo, F.; Merkel, P.; Merkel, R.; Mertens, V.; Merz, F.; Mlynek, A.; Monaco, F.; Müller, S.; H.W. Müller,; M. Münich,; Neu, G.; Neu, R.; Neuwirth, D.; Nocente, M.; Nold, B.; Noterdaeme, J. M.; Pautasso, G.; Pereverzev, G.; B. Plöckl,; Podoba, Y.; Pompon, F.; Poli, E.; Polozhiy, K.; Potzel, S.; Puschel, M. J.; Putterich, T.; Rathgeber, S. K.; Raupp, G.; Reich, M.; Reimold, F.; Ribeiro, T.; Riedl, R.; Rohde, V.; van Rooij, G. J.; Roth, J.; Rott, M.; Ryter, F.; Salewski, M.; Santos, J.; Sauter, P.; Scarabosio, A.; Schall, G.; Schmid, K.; Schneider, P. A.; Schneider, W.; Schrittwieser, R.; Schubert, M.; Schweinzer, J.; Scott, B.; Sempf, M.; Sertoli, M.; Siccinio, M.; Sieglin, B.; Sigalov, A.; Silva, A.; Sommer, F.; A. Stäbler,; Stober, J.; Streibl, B.; Strumberger, E.; Sugiyama, K.; Suttrop, W.; Tala, T.; Tardini, G.; Teschke, M.; Tichmann, C.; Told, D.; Treutterer, W.; Tsalas, M.; VanZeeland, M. A.; Varela, P.; Veres, G.; Vicente, J.; Vianello, N.; Vierle, T.; Viezzer, E.; Viola, B.; Vorpahl, C.; Wachowski, M.; Wagner, D.; Wauters, T.; Weller, A.; Wenninger, R.; Wieland, B.; Willensdorfer, M.; Wischmeier, M.; Wolfrum, E.; E. Würsching,; Yu, Q.; Zammuto, I.; Zasche, D.; Zehetbauer, T.; Zhang, Y.; Zilker, M.; Zohm, H.

    2013-01-01

    The medium size divertor tokamak ASDEX Upgrade (major and minor radii 1.65 m and 0.5 m, respectively, magnetic-field strength 2.5 T) possesses flexible shaping and versatile heating and current drive systems. Recently the technical capabilities were extended by increasing the electron cyclotron

  11. Overview of ASDEX Upgrade results

    DEFF Research Database (Denmark)

    Kallenbach, A.; Adamek, J.; Aho-Mantila, L.

    2011-01-01

    The ASDEX Upgrade programme is directed towards physics input to critical elements of the ITER design and the preparation of ITER operation, as well as addressing physics issues for a future DEMO design. After the finalization of the tungsten coating of the plasma facing components, the re-availa...

  12. Overview of ASDEX Upgrade results

    DEFF Research Database (Denmark)

    Stroth, U.; Adamek, J.; Aho-Mantila, L.

    2013-01-01

    The medium size divertor tokamak ASDEX Upgrade (major and minor radii 1.65 m and 0.5 m, respectively, magnetic-field strength 2.5 T) possesses flexible shaping and versatile heating and current drive systems. Recently the technical capabilities were extended by increasing the electron cyclotron r...

  13. Overview of ASDEX Upgrade results

    NARCIS (Netherlands)

    Kallenbach, A.; Adamek, J.; Aho-Mantila, L.; Akaslompolo, S.; Angioni, C.; Atanasiu, C. V.; Balden, M.; Behler, K.; Belonohy, E.; Bergmann, A.; Bernert, M.; Bilato, R.; Bobkov, V.; Boom, J.; Bottino, A.; Braun, F.; Brudgam, M.; Buhler, A.; Burckhart, A.; Chankin, A.; Classen, I.G.J.; Conway, G. D.; Coster, D. P.; de Marne, P.; D' Inca, R.; Drube, R.; Dux, R.; Eich, T.; Endstrasser, N.; Engelhardt, K.; Esposito, B.; Fable, E.; Fahrbach, H. U.; Fattorini, L.; Fischer, R.; Flaws, A.; Funfgelder, H.; Fuchs, J. C.; Gal, K.; Munoz, M. G.; Geiger, B.; Adamov, M. G.; Giannone, L.; Giroud, C.; Gorler, T.; da Graca, S.; Greuner, H.; Gruber, O.; Gude, A.; Gunter, S.; Haas, G.; Hakola, A. H.; Hangan, D.; Happel, T.; Hauff, T.; Heinemann, B.; Herrmann, A.; Hicks, N.; Hobirk, J.; Hohnle, H.; Holzl, M.; Hopf, C.; Horton, L.; Huart, M.; Igochine, V.; Ionita, C.; Janzer, A.; Jenko, F.; Kasemann, C. P.; Kalvin, S.; Kardaun, O.; Kaufmann, M.; Kirk, A.; Klingshirn, H. J.; Kocan, M.; Kocsis, G.; Kollotzek, H.; Konz, C.; Koslowski, R.; Krieger, K.; Kurki-Suonio, T.; Kurzan, B.; Lackner, K.; Lang, P. T.; Lauber, P.; Laux, M.; Leipold, F.; Leuterer, F.; Lohs, A.; N C Luhmann Jr.,; Lunt, T.; Lyssoivan, A.; Maier, H.; Maggi, C.; Mank, K.; Manso, M. E.; Maraschek, M.; Martin, P.; Mayer, M.; McCarthy, P. J.; McDermott, R.; Meister, H.; Menchero, L.; Meo, F.; Merkel, P.; Merkel, R.; Mertens, V.; Merz, F.; Mlynek, A.; Monaco, F.; Muller, H. W.; Munich, M.; Murmann, H.; Neu, G.; Neu, R.; Nold, B.; Noterdaeme, J. M.; Park, H. K.; Pautasso, G.; Pereverzev, G.; Podoba, Y.; Pompon, F.; Poli, E.; Polochiy, K.; Potzel, S.; Prechtl, M.; Puschel, M. J.; Putterich, T.; Rathgeber, S. K.; Raupp, G.; Reich, M.; Reiter, B.; Ribeiro, T.; Riedl, R.; Rohde, V.; Roth, J.; Rott, M.; Ryter, F.; Sandmann, W.; Santos, J.; Sassenberg, K.; Sauter, P.; Scarabosio, A.; Schall, G.; Schmid, K.; Schneider, P. A.; Schneider, W.; Schramm, G.; Schrittwieser, R.; Schweinzer, J.; Scott, B.; Sempf, M.; Serra, F.; Sertoli, M.; Siccinio, M.; Sigalov, A.; Silva, A.; Sips, A.C.C.; Sommer, F.; Stabler, A.; Stober, J.; Streibl, B.; Strumberger, E.; Sugiyama, K.; Suttrop, W.; Szepesi, T.; Tardini, G.; Tichmann, C.; Told, D.; Treutterer, W.; Urso, L.; Varela, P.; Vincente, J.; Vianello, N.; Vierle, T.; Viezzer, E.; Vorpahl, C.; Wagner, D.; Weller, A.; Wenninger, R.; Wieland, B.; Wigger, C.; Willensdorfer, M.; Wischmeier, M.; Wolfrum, E.; Wursching, E.; Yadikin, D.; Yu, Q.; Zammuto, I.; Zasche, D.; Zehetbauer, T.; Zhang, Y.; Zilker, M.; Zohm, H.

    2011-01-01

    The ASDEX Upgrade programme is directed towards physics input to critical elements of the ITER design and the preparation of ITER operation, as well as addressing physics issues for a future DEMO design. After the finalization of the tungsten coating of the plasma facing components, the

  14. Overview of ASDEX Upgrade results

    DEFF Research Database (Denmark)

    Zohm, H.; Adamek, J.; Angioni, C.

    2009-01-01

    ASDEX Upgrade was operated with a fully W-covered wall in 2007 and 2008. Stationary H-modes at the ITER target values and improved H-modes with H up to 1.2 were run without any boronization. The boundary conditions set by the full W wall (high enough ELM frequency, high enough central heating and...

  15. Overview of ASDEX Upgrade results

    DEFF Research Database (Denmark)

    Kallenbach, A.; Aguiam, D.; Aho-Mantila, L.

    2017-01-01

    The ASDEX Upgrade (AUG) programme is directed towards physics input to critical elements of the ITER design and the preparation of ITER operation, as well as addressing physics issues for a future DEMO design. Since 2015, AUG is equipped with a new pair of 3-strap ICRF antennas, which were design...

  16. Numerically derived parametrisation of optimal RMP coil phase as a guide to experiments on ASDEX Upgrade

    Science.gov (United States)

    Ryan, D. A.; Liu, Y. Q.; Li, L.; Kirk, A.; Dunne, M.; Dudson, B.; Piovesan, P.; Suttrop, W.; Willensdorfer, M.; the ASDEX Upgrade Team; the EUROfusion MST1 Team

    2017-02-01

    Edge localised modes (ELMs) are a repetitive MHD instability, which may be mitigated or suppressed by the application of resonant magnetic perturbations (RMPs). In tokamaks which have an upper and lower set of RMP coils, the applied spectrum of the RMPs can be tuned for optimal ELM control, by introducing a toroidal phase difference {{Δ }}{{Φ }} between the upper and lower rows. The magnitude of the outermost resonant component of the RMP field | {b}{{res}}1| (other proposed criteria are discussed herein) has been shown experimentally to correlate with mitigated ELM frequency, and to be controllable by {{Δ }}{{Φ }} (Kirk et al 2013 Plasma Phys. Control. Fusion 53 043007). This suggests that ELM mitigation may be optimised by choosing {{Δ }}{{Φ }}={{Δ }}{{{Φ }}}{{opt}}, such that | {b}{{res}}1| is maximised. However it is currently impractical to compute {{Δ }}{{{Φ }}}{{opt}} in advance of experiments. This motivates this computational study of the dependence of the optimal coil phase difference {{Δ }}{{{Φ }}}{{opt}}, on global plasma parameters {β }N and q 95, in order to produce a simple parametrisation of {{Δ }}{{{Φ }}}{{opt}}. In this work, a set of tokamak equilibria spanning a wide range of ({β }N, q 95) is produced, based on a reference equilibrium from an ASDEX Upgrade experiment. The MARS-F code (Liu et al 2000 Phys. Plasmas 7 3681) is then used to compute {{Δ }}{{{Φ }}}{{opt}} across this equilibrium set for toroidal mode numbers n = 1-4, both for the vacuum field and including the plasma response. The computational scan finds that for fixed plasma boundary shape, rotation profiles and toroidal mode number n, {{Δ }}{{{Φ }}}{{opt}} is a smoothly varying function of ({β }N, q 95). A 2D quadratic function in ({β }N, q 95) is used to parametrise {{Δ }}{{{Φ }}}{{opt}}, such that for given ({β }N, q 95) and n, an estimate of {{Δ }}{{{Φ }}}{{opt}} may be made without requiring a plasma response computation. To quantify the uncertainty

  17. Actuator management for ECRH at ASDEX Upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Rapson, Christopher J., E-mail: chris.rapson@ipp.mpg.de; Reich, Matthias; Stober, Joerg; Treutterer, Wolfgang

    2015-10-15

    Highlights: • Real-time actuator management algorithm developed for ECRH at ASDEX Upgrade. • First use of a control hierarchy in a fusion experiment. • Cost function evaluates optimal combination of all gyrotrons to all possible targets. • Considers many factors e.g. mirror movement, power available, presence and mode number of NTMs. • Configurable, robust algorithm is ready for online testing. - Abstract: Automated actuator management will be necessary on long pulse fusion experiments to adjust to unforeseen plasma events and unpredictable actuator availability. However, as a control problem, actuator management is underdeveloped in the fusion community. This contribution proposes an algorithm based on a control hierarchy and a cost function to optimally allocate scarce actuator resources to various objectives in real-time. Details are given on the development and offline testing which have been completed ready for deployment at ASDEX Upgrade. Electron Cyclotron Resonance Heating (ECRH) is particularly relevant for actuator management due to its localised deposition which can flexibly target specific regions of the plasma for different effects such as non-inductive current drive, impurity regulation, control of MHD modes and of course heating. A further motivation is that automated actuator management will simplify the setup of ECRH, in keeping with the long term goal of integrating MHD control as a routine part of ASDEX Upgrade experiments.

  18. Actuator management for ECRH at ASDEX Upgrade

    International Nuclear Information System (INIS)

    Rapson, Christopher J.; Reich, Matthias; Stober, Joerg; Treutterer, Wolfgang

    2015-01-01

    Highlights: • Real-time actuator management algorithm developed for ECRH at ASDEX Upgrade. • First use of a control hierarchy in a fusion experiment. • Cost function evaluates optimal combination of all gyrotrons to all possible targets. • Considers many factors e.g. mirror movement, power available, presence and mode number of NTMs. • Configurable, robust algorithm is ready for online testing. - Abstract: Automated actuator management will be necessary on long pulse fusion experiments to adjust to unforeseen plasma events and unpredictable actuator availability. However, as a control problem, actuator management is underdeveloped in the fusion community. This contribution proposes an algorithm based on a control hierarchy and a cost function to optimally allocate scarce actuator resources to various objectives in real-time. Details are given on the development and offline testing which have been completed ready for deployment at ASDEX Upgrade. Electron Cyclotron Resonance Heating (ECRH) is particularly relevant for actuator management due to its localised deposition which can flexibly target specific regions of the plasma for different effects such as non-inductive current drive, impurity regulation, control of MHD modes and of course heating. A further motivation is that automated actuator management will simplify the setup of ECRH, in keeping with the long term goal of integrating MHD control as a routine part of ASDEX Upgrade experiments.

  19. Runaway electron mitigation by 3D fields in the ASDEX-Upgrade experiment

    Science.gov (United States)

    Gobbin, M.; Li, L.; Liu, Y. Q.; Marrelli, L.; Nocente, M.; Papp, G.; Pautasso, G.; Piovesan, P.; Valisa, M.; Carnevale, D.; Esposito, B.; Giacomelli, L.; Gospodarczyk, M.; McCarthy, P. J.; Martin, P.; Suttrop, W.; Tardocchi, M.; Teschke, M.; the ASDEX Upgrade Team; the EUROfusion MST1 Team

    2018-01-01

    Disruption-generated runaway electron (RE) beams represent a severe threat for tokamak plasma-facing components in high current devices like ITER, thus motivating the search of mitigation techniques. The application of 3D fields might aid this purpose and recently was investigated also in the ASDEX Upgrade experiment by using the internal active saddle coils (termed B-coils). Resonant magnetic perturbations (RMPs) with dominant toroidal mode number n = 1 have been applied by the B-coils, in a RE specific scenario, before and during disruptions, which are deliberately created via massive gas injection. The application of RMPs affects the electron temperature profile and seemingly changes the dynamics of the disruption; this results in a significantly reduced current and lifetime of the generated RE beam. A similar effect is observed also in the hard-x-ray (HXR) spectrum, associated to RE emission, characterized by a partial decrease of the energy content below 1 MeV when RMPs are applied. The strength of the observed effects strongly depends on the upper-to-lower B-coil phasing, i.e. on the poloidal spectrum of the applied RMPs, which has been reconstructed including the plasma response by the code MARS-F. A crude vacuum approximation fails in the interpretation of the experimental findings: despite the relatively low β (< 0.5 % ) of these discharges, a modest amplification (factor of 2) of the edge kink response occurs, which has to be considered to explain the observed suppression effects.

  20. ASDEX upgrade - definition of a tokamak experiment with a reactor compatible polaoidal divertor

    International Nuclear Information System (INIS)

    1982-03-01

    ASDEX Upgrade is intended as the next experimental step after ASDEX. It is designed to investigate the physics of a divertor tokamak as closely as possible to fusion reactor requirements, without thermonuclear heating. It is characterized by a poloidal divertor configuration with divertor coils located outside the toroidal field coils, by machine parameters which allow a line density within the plasma boundary sufficient to screen fast CX particles from the plasma core, by a scrape-off layer essentially opaque to neutrals produced at the target plates, and, finally, by an auxiliary heating power high enough for producing a reactor-like power flux density through the plasma boundary. Design considerations on the basis of physical and technical constraints yielded the tokamak system optimized with respect to effort and costs as described in the following. It uses normal-conducting coil systems, is the size of ASDEX, and has a field of 3.9 T, a plasma current of up to 1.5 MA, and a pulse duration of 10 s. To provide the required power flux density, an ICRH power of 10 MW is needed. For comparison, a superconducting version is under investigation. (orig.)

  1. The ASDEX Upgrade Parameter Server

    Energy Technology Data Exchange (ETDEWEB)

    Neu, Gregor, E-mail: gregor.neu@ipp.mpg.de [Max-Planck-Institut für Plasmaphysik, Boltzmannstr. 2, 85748 Garching (Germany); Cole, Richard [Unlimited Computer Systems, Seeshaupter Str. 15, 82393 Iffeldorf (Germany); Gräter, Alex [Max-Planck-Institut für Plasmaphysik, Boltzmannstr. 2, 85748 Garching (Germany); Lüddecke, Klaus [Unlimited Computer Systems, Seeshaupter Str. 15, 82393 Iffeldorf (Germany); Rapson, Christopher J.; Raupp, Gerhard; Treutterer, Wolfgang; Zasche, Dietrich; Zehetbauer, Thomas [Max-Planck-Institut für Plasmaphysik, Boltzmannstr. 2, 85748 Garching (Germany)

    2015-10-15

    Highlights: • We describe our main tool in the plasma control configuration process. • Parameter access and computation are configurable with XML files. • Simple implementation of in situ tests by rerouting requests to test data. • Pulse specific overriding of parameters. - Abstract: Concepts for the configuration of plant systems and plasma control of modern devices such as ITER and W7-X are based on global data structures, or “pulse schedules” or “experiment programs”, which specify all physics characteristics (waveforms for controlled actuators and plasma quantities) and all technical characteristics of the plant systems (diagnostics and actuators operation settings) for a planned pulse. At ASDEX Upgrade we use different approach. We observed that the physics characteristics driving the discharge control system (DCS) are frequently modified on a pulse-to-pulse basis. Plant system operation, however, relies on technical standard settings, or “basic configurations” to provide guaranteed resources or services, which evolve according to longer term session or campaign operation schedules. This is why AUG manages technical configuration items separately from physics items. Consistent computation of the DCS configuration requires access to all this physics and technical data, which include the discharge programme (DP), settings of actuator systems and real-time diagnostics, the current system state and a database of static parameters. A Parameter Server provides a unified view on all these parameter sets and acts as the central point of access. We describe the functionality and architecture of the Parameter Server and its embedding into the control environment.

  2. Experiments on transient melting of tungsten by ELMs in ASDEX Upgrade

    Science.gov (United States)

    Krieger, K.; Balden, M.; Coenen, J. W.; Laggner, F.; Matthews, G. F.; Nille, D.; Rohde, V.; Sieglin, B.; Giannone, L.; Göths, B.; Herrmann, A.; de Marne, P.; Pitts, R. A.; Potzel, S.; Vondracek, P.; ASDEX-Upgrade Team; EUROfusion MST1 Team

    2018-02-01

    Repetitive melting of tungsten by power transients originating from edge localized modes (ELMs) has been studied in ASDEX Upgrade. Tungsten samples were exposed to H-mode discharges at the outer divertor target plate using the divertor manipulator II (DIM-II) system (Herrmann et al 2015 Fusion Eng. Des. 98-9 1496-9). Designed as near replicas of the geometries used also in separate experiments on the JET tokamak (Coenen et al 2015 J. Nucl. Mater. 463 78-84 Coenen et al 2015 Nucl. Fusion 55 023010; Matthews et al 2016 Phys. Scr. T167 7), the samples featured a misaligned leading edge and a sloped ridge respectively. Both structures protrude above the default target plate surface thus receiving an increased fraction of the parallel power flux. Transient melting by ELMs was induced by moving the outer strike point to the sample location. The temporal evolution of the measured current flow from the samples to vessel potential confirmed transient melting. Current magnitude and dependency from surface temperature provided strong evidence for thermionic electron emission as main origin of the replacement current driving the melt motion. The different melt patterns observed after exposures at the two sample geometries support the thermionic electron emission model used in the MEMOS melt motion code, which assumes a strong decrease of the thermionic net current at shallow magnetic field to surface angles (Pitts et al 2017 Nucl. Mater. Energy 12 60-74). Post exposure ex situ analysis of the retrieved samples show recrystallization of tungsten at the exposed surface areas to a depth of up to several mm. The melt layer transport to less exposed surface areas leads to ratcheting pile up of re-solidified debris with zonal growth extending from the already enlarged grains at the surface.

  3. The ASDEX Upgrade discharge schedule

    International Nuclear Information System (INIS)

    Neu, G.; Engelhardt, K.; Raupp, G.; Treutterer, W.; Zasche, D.; Zehetbauer, T.

    2007-01-01

    ASDEX Upgrade's recently commissioned discharge control system (DCS) marks the transition from a traditional programmed system to a highly flexible 'data driven' one. The allocation of application processes (APs) to controllers, the interconnection of APs through uniquely named signals, and AP control parameter values are all defined as data, and can easily be adapted to the requirements of a particular discharge. The data is laid down in a set of XML documents which APs request via HTTP from a configuration server before a discharge. The use of XML allows for easy parsing, and structural validation through (XSD) schemas. The central input to the configuration process is the discharge schedule (DS), which embodies the dynamic behaviour of a planned discharge as reference trajectories grouped in segments, concatenated through transition conditions. Editing, generation and validation tools, and version control through CVS allow for efficient management of DSs

  4. Overview of ASDEX Upgrade results

    Science.gov (United States)

    A. Kallenbachthe ASDEX Upgrade Team; the EUROfusion MST1 Team

    2017-10-01

    The ASDEX Upgrade (AUG) programme is directed towards physics input to critical elements of the ITER design and the preparation of ITER operation, as well as addressing physics issues for a future DEMO design. Since 2015, AUG is equipped with a new pair of 3-strap ICRF antennas, which were designed for a reduction of tungsten release during ICRF operation. As predicted, a factor two reduction on the ICRF-induced W plasma content could be achieved by the reduction of the sheath voltage at the antenna limiters via the compensation of the image currents of the central and side straps in the antenna frame. There are two main operational scenario lines in AUG. Experiments with low collisionality, which comprise current drive, ELM mitigation/suppression and fast ion physics, are mainly done with freshly boronized walls to reduce the tungsten influx at these high edge temperature conditions. Full ELM suppression and non-inductive operation up to a plasma current of {{I}\\text{p}}=0.8 MA could be obtained at low plasma density. Plasma exhaust is studied under conditions of high neutral divertor pressure and separatrix electron density, where a fresh boronization is not required. Substantial progress could be achieved for the understanding of the confinement degradation by strong D puffing and the improvement with nitrogen or carbon seeding. Inward/outward shifts of the electron density profile relative to the temperature profile effect the edge stability via the pressure profile changes and lead to improved/decreased pedestal performance. Seeding and D gas puffing are found to effect the core fueling via changes in a region of high density on the high field side (HFSHD). The integration of all above mentioned operational scenarios will be feasible and naturally obtained in a large device where the edge is more opaque for neutrals and higher plasma temperatures provide a lower collisionality. The combination of exhaust control with pellet fueling has been successfully

  5. MHD equilibrium identification on ASDEX-Upgrade

    International Nuclear Information System (INIS)

    McCarthy, P.J.; Schneider, W.; Lakner, K.; Zehrfeld, H.P.; Buechl, K.; Gernhardt, J.; Gruber, O.; Kallenbach, A.; Lieder, G.; Wunderlich, R.

    1992-01-01

    A central activity accompanying the ASDEX-Upgrade experiment is the analysis of MHD equilibria. There are two different numerical methods available, both using magnetic measurements which reflect equilibrium states of the plasma. The first method proceeds via a function parameterization (FP) technique, which uses in-vessel magnetic measurements to calculate up to 66 equilibrium parameters. The second method applies an interpretative equilibrium code (DIVA) for a best fit to a different set of magnetic measurements. Cross-checks with the measured particle influxes from the inner heat shield and the divertor region and with visible camera images of the scrape-off layer are made. (author) 3 refs., 3 figs

  6. Disruption studies on ASDEX upgrade

    International Nuclear Information System (INIS)

    Pautasso, G.; Egorov, S.; Finken, K.H.

    2003-01-01

    Disruptions generate large thermal and mechanical stresses on the tokamak components and are occasionally responsible for damages to the machine. For a future reactor disruptions have a significant impact on the design since all loading conditions must be analyzed in accordance with stricter design criteria (due to safety or difficult maintenance). Therefore the uncertainties affecting the predicted stresses must be reduced as much as possible with a more comprehensive set of measurements and analyses in this generation of experimental machines, and avoidance/predictive methods must be developed further. Disruption studies on ASDEX Upgrade are focused on these subjects, namely on: (1) understanding the physical mechanisms leading to this phenomenon in order to learn to avoid it or to predict its occurrence and to mitigate its effects; (2) analyzing the effects of disruptions on the machine to determine the functional dependence of the thermal and mechanical loads upon the discharge parameters. This allows, firstly, to dimension or reinforce the machine components to withstand these loads and, secondly, to extrapolate them to tokamaks still in the design phase; (3) learning to mitigate the consequence of disruptions, i.e. thermal loads, mechanical forces and runaways with injection of impurity pellets or gas. This paper is focused on most recent results concerning points, i.e. on the analysis of the degree of asymmetry of the forces and on the use of impurity puff for mitigation

  7. Regime identification in ASDEX Upgrade

    International Nuclear Information System (INIS)

    Giannone, L; Sips, A C C; Kardaun, O; Spreitler, F; Suttrop, W

    2004-01-01

    The ability to recognize the transition from the L-mode to the H-mode or from the H-mode to the improved H-mode reliably from a conveniently small number of measurements in real time is of increasing importance for machine control. Discriminant analysis has been applied to regime identification of plasma discharges in the ASDEX Upgrade tokamak. An observation consists of a set of plasma parameters averaged over a time slice in a discharge. The data set consists of all observations over different discharges and time slices. Discriminant analysis yields coefficients allowing the classification of a new observation. The results of a frequentist and a formal Bayesian approach to discriminant analysis are compared. With five plasma variables, a failure rate of 1.3% for predicting the L-mode and the H-mode confinement regime was achieved. With five plasma variables, a failure rate of 5.3% for predicting the H-mode and the improved H-mode confinement regime was achieved. The coefficients derived by discriminant analysis have been applied subsequently to discharges to illustrate the operation of regime identification in a real time control system

  8. Disruption studies in ASDEX Upgrade

    International Nuclear Information System (INIS)

    Pautasso, G.

    2002-01-01

    Disruption generate large thermal and mechanical stresses on the tokamak components. For a future reactor disruptions have a significant impact on the design since all loading conditions must be analyzed in accordance with stricter design criteria (due to safety or difficult maintenance). Therefore the uncertainties affecting the predicted stresses must be reduced as much as possible with a more comprehensive set of measurements and analyses in this generation of experimental machines, and avoidance/ predictive methods must be developed further. The study of disruptions on ASDEX Upgrade is focused on these subjects, namely on: (1) understanding the physical mechanisms leading to this phenomenon and learning to avoid it or to predict its occurrence (with neural networks, for example) and to mitigate its effects; (2) analyzing the effects of disruptions on the machine to determine the functional dependence of the thermal and mechanical loads upon the discharge parameters. This allows to dimension or reinforce the machine components to withstand these loads and to extrapolate them to tokamaks still in the design phase; (3) learning to mitigate the consequence of disruptions. (author)

  9. Commissioning and initial operation experience with ASDEX Upgrade's new real-time control and data acquisition

    International Nuclear Information System (INIS)

    Raupp, G.; Behler, K.; Cole, R.; Engelhardt, K.; Lohs, A.; Lueddecke, K.; Treutterer, W.; Neu, G.; Vijverberg, T.; Zasche, D.; Zehetbauer, Th.

    2006-01-01

    ASDEX Upgrade was equipped with a distributed real-time (RT) control and diagnostic system. Application processes can be freely mapped onto controllers. They communicate through RT data exchanged via a shared memory network. Processes run self-organized with a data-driven scheme, i.e. a process executes when all required data has become available and produced data drive other processes waiting for these. The process chain starts periodically through a time-synchronous cycle master process to deterministically execute closed-loop control. Generic processes were implemented for feedback of plasma position and shape, and for performance control with fuelling and heating systems, for evaluation and monitoring of plasma quantities and Tokamak components, and generation of reference values in RT. Upon commissioning the system was speed-optimized to run a 1.6 ms cycle. Methods to exchange data and time information in RT and operate distributed data-driven processes work efficiently and reliably. The ability to freely map processes to computing nodes and RT data to generic processes provides outstanding configurational flexibility for optimizing system performance or supporting in situ replay and simulation runs. In the computation of reference values in RT acting on underlying feedback controllers, demonstrated for soft-landing, we see great potential to counteract instabilities or optimize pulses

  10. Determination of the stochastic layer properties induced by magnetic perturbations via heat pulse experiments at ASDEX upgrade

    Czech Academy of Sciences Publication Activity Database

    Brida, D.; Lunt, T.; Wischmeier, M.; Birkenmeier, G.; Cahyna, Pavel; Carralero, D.; Faitsch, M.; Feng, Y.; Kurzan, B.; Schubert, M.; Sieglin, B.; Suttrop, W.; Wolfrum, E.

    2017-01-01

    Roč. 12, August (2017), s. 831-837 ISSN 2352-1791 EU Projects: European Commission(XE) 633053 - EUROfusion Institutional support: RVO:61389021 Keywords : ASDEX upgrade * Magnetic perturbations * Divertor heat flux Subject RIV: BL - Plasma and Gas Discharge Physics OBOR OECD: Fluids and plasma physics (including surface physics) http://www.sciencedirect.com/science/article/pii/S2352179116302150

  11. Performance of the first ASDEX Upgrade neutral beam injector

    International Nuclear Information System (INIS)

    Staebler, A.; Vollmer, O.; Feist, J.H.; Speth, E.; Heinemann, B.; Melkus, W.; Obermayer, S.; Riedl, R.; Schaerich, W.; Wittenbecher, K.

    1995-01-01

    Plasmas of the ASDEX Upgrade tokamak have been heated with H 0 beams of up to 7 MW and D 0 beams of up to 10 MW. Beam modulation allows to inject at any power level between zero and full power. Measurements characterizing the NBI system performance, the power accountability, and the operational experience obtained so far are discussed. (orig.)

  12. Overview of ASDEX Upgrade results

    Czech Academy of Sciences Publication Activity Database

    Stroth, U.; Adámek, Jiří; Aho-Mantila, L.; Äkäslompolo, S.; Amdor, C.; Angioni, C.; Balden, M.; Bardin, S.; Barrera Orte, L.; Behler, K.; Belonohy, E.; Bergmann, A.; Bernert, M.; Bilato, R.; Birkenmeier, G.; Bobkov, V.; Boom, J.; Bottereau, C.; Bottino, A.; Braun, F.; Brezinsek, S.; Brochard, T.; Brüdgam, M.; Buhler, A.; Burckhart, A.; Casson, F.J.; Chankin, A.; Chapman, I.; Clairet, F.; Classen, I.G.J.; Coenen, J.W.; Conway, G.D.; Coster, D.P.; Curran, D.; da Silva, F.; de Marné, P.; D’Inca, R.; Douai, D.; Drube, R.; Dunne, M.; Dux, R.; Eich, T.; Eixenberger, H.; Endstrasser, N.; Engelhardt, K.; Esposito, B.; Fable, E.; Fischer, R.; Fünfgelder, H.; Fuchs, J.C.; Gál, K.; García Munoz, M.; Geiger, B.; Giannone, L.; Görler, T.; da Graca, S.; Greuner, H.; Gruber, O.; Gude, A.; Guimarais, L.; Günter, S.; Haas, G.; Hakola, A.H.; Hangan, D.; Happel, T.; Härtl, T.; Hauff, T.; Heinemann, B.; Herrmann, A.; Hobirk, J.; Höhnle, H.; Hölzl, M.; Hopf, C.; Igochine, V.; Ionita, C.; Janzer, A.; Jenko, F.; Käsemann, C.-P.; Kallenbach, A.; Kálvin, S.; Kantor, M.; Kappatou, A.; Kardaun, O.; Kasparek, W.; Kaufmann, M.; Kirk, A.; Klingshirn, H.-J.; Kocan, M.; Kocsis, G.; Konz, C.; Koslowski, R.; Krieger, K.; Kubic, M.; Kurki-Suonio, T.; Kurzan, B.; Lackner, K.; Lang, P.T.; Lauber, P.; Laux, M.; Lazaros, A.; Leipold, F.; Leuterer, F.; Lindig, S.; Lisgo, S.; Lohs, A.; Lunt, T.; Maier, H.; Makkonen, T.; Mank, K.; Manso, M.-E.; Maraschek, M.; Mayer, M.; McCarthy, P.J.; McDermott, R.; Mehlmann, F.; Meister, H.; Menchero, L.; Meo, F.; Merkel, P.; Merkel, R.; Mertens, V.; Merz, F.; Mlynek, A.; Monaco, F.; Müller, S.; Müller, H.W.; Münich, M.; Neu, G.; Neu, R.; Neuwirth, D.; Nocente, M.; Nold, B.; Noterdaeme, J.-M.; Pautasso, G.; Pereverzev, G.; Plöckl, B.; Podoba, Y.; Pompon, F.; Poli, E.; Polozhiy, K.; Potzel, S.; Püschel, M.J.; Pütterich, T.; Rathgeber, S.K.; Raupp, G.; Reich, M.; Reimold, M.; Ribeiro, T.; Riedl, R.; Rohde, V.; v.Rooij, G.; Roth, J.; Rott, M.; Ryter, F.; Salewski, M.; Santos, J.; Sauter, P.; Scarabosio, A.; Schall, G.; Schmid, K.; Schneider, P.A.; Schneider, W.; Schrittwieser, R.; Schubert, M.; Schweinzer, J.; Scott, B.; Sempf, M.; Sertoli, M.; Siccinio, M.; Sieglin, B.; Sigalov, A.; Silva, A.; Sommer, F.; Stäbler, A.; Stober, J.; Streibl, B.; Strumberger, E.; Sugiyama, K.; Suttrop, W.; Tala, T.; Tardini, G.; Teschner, M.; Tichmann, C.; Told, D.; Treutterer, W.; Tsalas, M.; Van Zeeland, M.A.; Varela, P.; Véres, G.; Vicente, J.; Vianello, N.; Vierle, T.; Viezzer, E.; Viola, B.; Vorpahl, C.; Wachowski, M.; Wagner, D.; Wauters, T.; Weller, A.; Wenninger, R.; Wieland, B.; Willensdorfer, M.; Wischmeier, M.; Wolfrum, E.; Würsching, E.; Yu, Q.; Zammuto, I.; Zasche, D.; Zehetbauer, T.; Zhang, Y.; Zilker, M.; Zohm, H.

    2013-01-01

    Roč. 53, č. 10 (2013), s. 104003-104003 ISSN 0029-5515. [IAEA Fusion Energy Conference/24./. San Diego, 08.10.2012-13.10.2012] Institutional support: RVO:61389021 Keywords : tokamak * ASDEX * ITER * ICRH system Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 3.243, year: 2013 http://m.iopscience.iop.org/0029-5515/53/10/104003/pdf/0029-5515_53_10_104003.pdf

  13. The enhanced ASDEX Upgrade pellet centrifuge launcher

    Energy Technology Data Exchange (ETDEWEB)

    Plöckl, B.; Lang, P. T. [Max Planck Institute for Plasma Physics, EURATOM Association, Boltzmannstr. 2, 85748 Garching (Germany)

    2013-10-15

    Pellets played an important role in the program of ASDEX Upgrade serving both for investigations on efficient particle fuelling and high density scenarios but also for pioneering work on Edge Localised Mode (ELM) pacing and mitigation. Initially designed for launching fuelling pellets from the magnetic low field side, the system was converted already some time ago to inject pellets from the magnetic high field side as much higher fuelling efficiency was found using this configuration. In operation for more than 20 years, the pellet launching system had to undergo a major revision and upgrading, in particular of its control system. Furthermore, the control system installed adjacent to the launcher had to be transferred to a more distant location enforcing a complete galvanic separation from torus potential and a fully remote control solution. Changing from a hybrid system consisting of PLC S5/S7 and some hard wired relay control to a state of the art PLC system allowed the introduction of several new operational options enabling more flexibility in the pellet experiments. This article describes the new system architecture of control hardware and software, the operating procedure, and the extended operational window. First successful applications for ELM pacing and triggering studies are presented as well as utilization for the development of high density scenarios.

  14. The enhanced ASDEX Upgrade pellet centrifuge launcher

    International Nuclear Information System (INIS)

    Plöckl, B.; Lang, P. T.

    2013-01-01

    Pellets played an important role in the program of ASDEX Upgrade serving both for investigations on efficient particle fuelling and high density scenarios but also for pioneering work on Edge Localised Mode (ELM) pacing and mitigation. Initially designed for launching fuelling pellets from the magnetic low field side, the system was converted already some time ago to inject pellets from the magnetic high field side as much higher fuelling efficiency was found using this configuration. In operation for more than 20 years, the pellet launching system had to undergo a major revision and upgrading, in particular of its control system. Furthermore, the control system installed adjacent to the launcher had to be transferred to a more distant location enforcing a complete galvanic separation from torus potential and a fully remote control solution. Changing from a hybrid system consisting of PLC S5/S7 and some hard wired relay control to a state of the art PLC system allowed the introduction of several new operational options enabling more flexibility in the pellet experiments. This article describes the new system architecture of control hardware and software, the operating procedure, and the extended operational window. First successful applications for ELM pacing and triggering studies are presented as well as utilization for the development of high density scenarios

  15. Determination of the stochastic layer properties induced by magnetic perturbations via heat pulse experiments at ASDEX upgrade

    Directory of Open Access Journals (Sweden)

    D. Brida

    2017-08-01

    Full Text Available A heat pulse experiment was carried out in the tokamak ASDEX Upgrade to estimate the stochastic layer width of a deuterium L-mode discharge with externally applied Magnetic Perturbations. The method relies on the deposition of ECRH pulses in the plasma edge while measuring the divertor target heat flux with high temporal resolution IR thermography and Langmuir probes. The experimental results were compared to simulations of the time dependent heat pulse propagation on a constant plasma background with the EMC3-EIRENE code package, using an ad-hoc screening model. If no screening was taken into account in the simulations a decrease in the characteristic heat pulse propagation time was observed, which shows that the heat transport is enhanced compared to the screened cases. No such enhancement was found in the experiment, indicating strong screening. In further simulations the effect of screening on the target fluxes was investigated for varying densities. For low densities it was found that screening reduces the strike line splitting strongly, while for higher densities no strong strike line splitting was found, independent of the screening degree. For strongly detached L-mode conditions with MPs experiments at AUG indicate that the lobe structures vanish completely.

  16. The deuterium inventory in ASDEX Upgrade

    International Nuclear Information System (INIS)

    Mayer, M.; Rohde, V.; Ramos, G; Vainonen-Ahlgren, E.; Likonen, J.; Herrmann, A.; Neu, R.

    2007-01-01

    The deuterium inventory in ASDEX Upgrade was determined by quantitative ion beam analysis techniques and SIMS for different discharge campaigns between the years 2002 and 2005. ASDEX Upgrade was a carbon dominated machine during this phase. Full poloidal sections of the lower and upper divertor tile surfaces, limiter tiles, gaps between divertor tiles, gaps between inner heat shield tiles and samples from remote areas below the roof baffle and in pump ducts were analysed, thus offering an exhaustive survey of all relevant areas in ASDEX Upgrade. Deuterium is mainly trapped on plasma-exposed surfaces of inner divertor tiles, where about 70% of the retained deuterium inventory is found. About 20% of the inventory is retained at or below the divertor roof baffle, and about 10% is observed in other areas, such as the outer divertor and in gaps between tiles. The long term deuterium retention is 3-4% of the total deuterium input. The obtained results are compared with gas balance measurements, and conclusions about tritium retention in ITER are made

  17. Three novel software tools for ASDEX Upgrade

    International Nuclear Information System (INIS)

    Martinov, S.; Löbhard, T.; Lunt, T.; Behler, K.; Drube, R.; Eixenberger, H.; Herrmann, A.; Lohs, A.; Lüddecke, K.; Merkel, R.; Neu, G.; ASDEX Upgrade Team; MPCDF Garching

    2016-01-01

    Highlights: • Key features of innovative software tools for data visualization and inspection are presented to the nuclear fusion research community. • 3D animation of experiment geometry together with diagnostic data and images allow better understanding of measurements and influence of machine construction details behind them. • Multi-video viewer with fusion relevant image manipulation abilities and event database features allows faster and better decision making from video streams coming from various plasma and machine diagnostics. • Platform independant Web technologies enable the inspection of diagnostic raw signals with virtually any kind of display device. - Abstract: Visualization of measurements together with experimental settings is a general subject in experiments analysis. The complex engineering design, 3D geometry, and manifold of diagnostics in larger fusion research experiments justify the development of special analysis and visualization programs. Novel ASDEX Upgrade (AUG) software tools bring together virtual navigation through 3D device models and advanced play-back and interpretation of video streams from plasma discharges. A third little tool allows the web-based platform independent observation of real-time diagnostic signals. While all three tools stem from spontaneous development ideas and are not considered mission critical for the operation of a fusion device, they with time and growing completeness shaped up as valuable helpers to visualize acquired data in fusion research. A short overview on the goals, the features, and the design as well as the operation of these tools is given in this paper.

  18. Three novel software tools for ASDEX Upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Martinov, S. [Max-Planck-Institut für Plasmaphysik, Boltzmannstr. 2, D-85748 Garching bei München (Germany); Löbhard, T. [Conovum GmbH & Co. KG, Nymphenburger Straße 13, D-80335 München (Germany); Lunt, T. [Max-Planck-Institut für Plasmaphysik, Boltzmannstr. 2, D-85748 Garching bei München (Germany); Behler, K., E-mail: karl.behler@ipp.mpg.de [Max-Planck-Institut für Plasmaphysik, Boltzmannstr. 2, D-85748 Garching bei München (Germany); Drube, R.; Eixenberger, H.; Herrmann, A.; Lohs, A. [Max-Planck-Institut für Plasmaphysik, Boltzmannstr. 2, D-85748 Garching bei München (Germany); Lüddecke, K. [Unlimited Computer Systems GmbH, Seeshaupterstr. 15, D-82393 Iffeldorf (Germany); Merkel, R.; Neu, G.; ASDEX Upgrade Team [Max-Planck-Institut für Plasmaphysik, Boltzmannstr. 2, D-85748 Garching bei München (Germany); MPCDF Garching [Max Planck Compu ting and Data Facility, Boltzmannstr. 2, D-85748 Garching (Germany)

    2016-11-15

    Highlights: • Key features of innovative software tools for data visualization and inspection are presented to the nuclear fusion research community. • 3D animation of experiment geometry together with diagnostic data and images allow better understanding of measurements and influence of machine construction details behind them. • Multi-video viewer with fusion relevant image manipulation abilities and event database features allows faster and better decision making from video streams coming from various plasma and machine diagnostics. • Platform independant Web technologies enable the inspection of diagnostic raw signals with virtually any kind of display device. - Abstract: Visualization of measurements together with experimental settings is a general subject in experiments analysis. The complex engineering design, 3D geometry, and manifold of diagnostics in larger fusion research experiments justify the development of special analysis and visualization programs. Novel ASDEX Upgrade (AUG) software tools bring together virtual navigation through 3D device models and advanced play-back and interpretation of video streams from plasma discharges. A third little tool allows the web-based platform independent observation of real-time diagnostic signals. While all three tools stem from spontaneous development ideas and are not considered mission critical for the operation of a fusion device, they with time and growing completeness shaped up as valuable helpers to visualize acquired data in fusion research. A short overview on the goals, the features, and the design as well as the operation of these tools is given in this paper.

  19. Pellet injection into ASDEX upgrade plasmas

    International Nuclear Information System (INIS)

    Lang, P.T.; Zohm, H.; Buechl, K.; Fuchs, J.C.; Gehre, O.; Gruber, O.; Lang, R.S.; Mertens, V.; Neuhauser, J.; Salzmann, H.

    1996-04-01

    This work comprises results obtained using the new centrifuge injection system for the two first years of pellet injection experiments at Asdex Upgrade until the end of the 1995 experimental campaign. The main aim of the pellet injection investigation is to develop scenarios allowing for a more flexible plasma density control means of injection of cryogenic solid hydrogen pellets. Efforts have been made to develop scenarios allowing more flexible plasma density control by injecting cryogenic solid hydrogen pellets. While the injection of pellets during ohmic discharges was found to be most efficient and also improves the plasma performance, increasing the auxiliary heating power causes a detoriation of the pellet fuelling efficiency. A further strong reduction of the pellet fuelling efficiency by an additional process was observed for the more reactor-relevant conditions of shallow particle deposition during H-mode phases. With injection during type I ELMy H-mode phases, each pellet was found to trigger the release of an ELM and therefore cause particle losses mainly from the edge region. In the type I ELMy H-mode, only sufficient pellet penetration allowed noticeable, persistent particle deposition in the plasma by the pellets. Applying adequate pellet injection conditions and favourable scenarios using combined pellet/gas puff refuelling, significant density ramp-up to densities exceeding the empirical Greenwald limit by up to a factor of two was achieved even for strongly heated H-mode plasmas. (orig.)

  20. Recent ECRH results in ASDEX upgrade

    International Nuclear Information System (INIS)

    Leuterer, F.; Dux, R.; Gantenbein, G.

    2003-01-01

    This paper provides an overview on recent experimental results obtained in ASDEX Upgrade using electron cyclotron heating and current drive. The following topics are covered: determination of the power deposition profile, modulated power deposition, studies of the electron heat transport via power balance and heat wave analysis and a comparison with turbulent transport theory, generation of an internal transport barrier for the electron heat flux, impact of electron cyclotron resonance heating (ECRH) on particle and impurity transport, and studies related to neoclassical tearing modes and to sawteeth. (author)

  1. Neoclassical tearing modes on ASDEX Upgrade: Improved scaling laws, high confinement at high βN and new stabilization experiments

    International Nuclear Information System (INIS)

    Guenter, S.; Gude, A.; Igochine, V.; Maraschek, M.; Sips, A.C.C.; Zohm, H.; Gantenbein, G.; Sauter, O.

    2003-01-01

    In this paper recent results on the physics of neoclassical tearing modes (NTMs) achieved on ASDEX Upgrade are reported. A scaling law for NTM decay has been found, showing that the minimum local bootstrap current density required for mode growth is proportional to the ion gyro radius. As this scaling law does not depend on the seed island size, and thus on the background MHD activity, it is more reliable than previously derived scaling laws for the NTM onset. Furthermore, the recently reported Frequently Interrupted Regime (FIR) is discussed. In this new regime (m,n) NTMs are characterized by frequent amplitude drops caused by interaction with (m+1,n+1) background MHD activity. Due to the resulting reduced time averaged island size this leads to lower confinement degradation compared to that caused by the usual NTMs. As shown here, the transition into this regime can actively be triggered by lowering the magnetic shear at the q=(m+1)/=(n+1) rational surface. Further investigations regard mechanisms to increase the β N value for NTM onset such as plasma shaping, seed island size and density profile control. Using these studies, a scenario with high β N (β N = 3:5) at high density (n/n GW = 0.83) and confinement (H 98(y,2) = 1.2) has been developed. Moreover, this scenario is characterized by type II ELM activity and thus by moderate heat load to the target plates. Finally, new NTM stabilization experiments are reported, demonstrating an increase in β N after NTM stabilization. (author)

  2. Feedback-controlled NTM stabilization on ASDEX Upgrade

    Directory of Open Access Journals (Sweden)

    Stober J.

    2015-01-01

    Full Text Available On ASDEX Upgrade a concept for real-time stabilization of NTMs has been realized and successfully applied to (3,2- and (2,1-NTMs. Since most of the work has meanwhile been published elsewhere, a short summary with the appropriate references is given. Limitations, deficits and future extensions of the system are discussed. In a second part the recent work on using modulated ECCD for NTM stabilisation is described in some detail. In these experiments ECCD power is modulated according to a magnetic footprint of the rotating NTM. In agreement with earlier results it could be shown that O-point heating reduces the necessary average power for stabilisation whereas X-point heating hampers stabilisation. Although this modulated scheme is not relevant for routine NTM stabilisation on ASDEX Upgrade it may be mandatory for ITER or DEMO. On ASDEX Upgrade it has been re-developed to demonstrate the usage of a FAst DIrectional Switch to continously heat the O-point of the rotating island with only one gyrotron switching between two launchers which target the mode at locations separated in phase by 180 degrees as described in [1].

  3. The halo current in ASDEX Upgrade

    International Nuclear Information System (INIS)

    Pautasso, G.; Giannone, L.; Gruber, O.; Herrmann, A.; Maraschek, M.; Schuhbeck, K.H.

    2011-01-01

    Due to the complexity of the phenomena involved, a self-consistent physical model for the prediction of the halo current is not available. Therefore the ITER specifications of the spatial distribution and evolution of the halo current rely on empirical assumptions. This paper presents the results of an extensive analysis of the halo current measured in ASDEX Upgrade with particular emphasis on the evolution of the halo region, on the magnitude and time history of the halo current, and on the structure and duration of its toroidal and poloidal asymmetries. The effective length of the poloidal path of the halo current in the vessel is found to be rather insensitive to plasma parameters. Large values of the toroidally averaged halo current are observed in both vertical displacement events and centred disruptions but last a small fraction of the current quench; they coincide typically with a large but short-lived MHD event.

  4. The halo current in ASDEX Upgrade

    Science.gov (United States)

    Pautasso, G.; Giannone, L.; Gruber, O.; Herrmann, A.; Maraschek, M.; Schuhbeck, K. H.; ASDEX Upgrade Team

    2011-04-01

    Due to the complexity of the phenomena involved, a self-consistent physical model for the prediction of the halo current is not available. Therefore the ITER specifications of the spatial distribution and evolution of the halo current rely on empirical assumptions. This paper presents the results of an extensive analysis of the halo current measured in ASDEX Upgrade with particular emphasis on the evolution of the halo region, on the magnitude and time history of the halo current, and on the structure and duration of its toroidal and poloidal asymmetries. The effective length of the poloidal path of the halo current in the vessel is found to be rather insensitive to plasma parameters. Large values of the toroidally averaged halo current are observed in both vertical displacement events and centred disruptions but last a small fraction of the current quench; they coincide typically with a large but short-lived MHD event.

  5. A solid tungsten divertor for ASDEX Upgrade

    International Nuclear Information System (INIS)

    Herrmann, A; Greuner, H; Jaksic, N; Böswirth, B; Maier, H; Neu, R; Vorbrugg, S

    2011-01-01

    The conceptual design of a solid tungsten divertor for ASDEX Upgrade (AUG) is presented. The Div-III design is compatible with the existing divertor structure. It re-establishes the energy and heat receiving capability of a graphite divertor and overcomes the limitations of tungsten coatings. In addition, a solid tungsten divertor allows us to investigate erosion and bulk deuterium retention as well as test castellation and target tilting. The design criteria as well as calculations of forces due to halo and eddy currents are presented. The thermal properties of the proposed sandwich structure are calculated with finite element method models. After extensive testing of a target tile in the high heat flux test facility GLADIS, two solid tungsten tiles were installed in AUG for in-situ testing.

  6. Recent Upgrades and Extensions of the ASDEX Upgrade ECRH System

    Science.gov (United States)

    Wagner, Dietmar; Stober, Jörg; Leuterer, Fritz; Monaco, Francesco; Münich, Max; Schmid-Lorch, Dominik; Schütz, Harald; Zohm, Hartmut; Thumm, Manfred; Scherer, Theo; Meier, Andreas; Gantenbein, Gerd; Flamm, Jens; Kasparek, Walter; Höhnle, Hendrik; Lechte, Carsten; Litvak, Alexander G.; Denisov, Gregory G.; Chirkov, Alexey; Popov, Leonid G.; Nichiporenko, Vadim O.; Myasnikov, Vadim E.; Tai, Evgeny M.; Solyanova, Elena A.; Malygin, Sergey A.

    2011-03-01

    The multi-frequency Electron Cyclotron Heating (ECRH) system at the ASDEX Upgrade tokamak employs depressed collector gyrotrons, step-tunable in the range 105-140 GHz. The system is equipped with a fast steerable launcher allowing for remote steering of the ECRH RF beam during the plasma discharge. The gyrotrons and the mirrors are fully integrated in the discharge control system. The polarization can be controlled in a feed-forward mode. 3 Sniffer probes for millimeter wave stray radiation detection have been installed.

  7. A large divertor manipulator for ASDEX Upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Herrmann, Albrecht, E-mail: albrecht.herrmann@ipp.mpg.de; Jaksic, Nikola; Leitenstern, Peter; Greuner, Henri; Krieger, Karl; Marné, Pascal de; Oberkofler, Martin; Rohde, Volker; Schall, Gerd

    2015-10-15

    Highlights: • A large divertor manipulator for ASDEX Upgrade is developed and tested. • It allows replacing a relevant part of the divertor by dedicated targets and probes. • Modified solid standard targets. • Electrical and mechanical probes for dedicated investigations. • Test of actively cooled component. - Abstract: In 2013 a new bulk tungsten divertor, Div-III, was installed in ASDEX Upgrade (AUG). During the concept and design phase of Div-III the option of adaptable divertor instrumentation and divertor modification as contribution for divertor investigations in preparation of ITER was given a high priority. To gain flexibility for the test of divertor modifications without affecting the operational space of AUG, the large divertor manipulator, DIM-II, was designed and installed. DIM-II allows to retract 2 out of 128 outer divertor target tiles including the water cooled support structure into a target exchange box and to replace these targets without breaking the vacuum of the AUG vessel. DIM-II is based on a carriage-rail system with a driving rod pushing a front-end with the target module into the divertor position for plasma operation. Three types of front-ends are foreseen for physics investigations: (i) modified standard targets clamped to the standard cooling structure, (ii) dedicated front-ends making use of the whole available volume of about 230 × 160 × 80 mm{sup 3} and (iii) actively cooled/heated targets for cooling water temperatures up to 230 °C. This paper presents the DIM-II design including the FEM calculations for the modified divertor support structure and the front-end options, as well as the test procedure and operation mode.

  8. ASDEX-UG. ASDEX upgrade project proposal. Phase 2

    International Nuclear Information System (INIS)

    1983-05-01

    The objective of ASDEX UG is to investigate the problems relating to tokamak divertor physics and the boundary layer of hot plasmas which cannot be covered otherwise by either ASDEX or other EUROPEAN tokamaks, including JET, but whose investigation is indispensable for NET and INTOR. The configuration of ASDEX UG is changed as compared with ASDEX due to the requirement that all poloidal field coils are located outside the toroidal field magnet. This leads to a highly elongated D-shaped plasma with an ''open'' divertor, which does not allow to close the divertor chamber by such simple means as in ASDEX. In section 2, the aims of ASDEX UG are repeated briefly and the essential features and parameters of the tokamak system are summarized. The summary includes an overview of the tokamak design, the time schedule of design and construction concluding with the estimated investment cost and manpower required. In section 3 the tokamak system components are treated. The circuits and energy supply for the different electrical components are described in section 4. Auxiliary heating requirements and methods are discussed in section 5. Section 6 presents a survey over the periphery of the tokamak system including preparation of the building and radiation shielding. Section 7 outlines the physical programme. Section 8 is devoted to diagnostics. Finally, the principal concepts for control, data acquisition and handling are outlined in section 9. (orig./AH)

  9. Comparison of runaway electron generation parameters in small, medium-sized and large tokamaks—A survey of experiments in COMPASS, TCV, ASDEX-Upgrade and JET

    Science.gov (United States)

    Plyusnin, V. V.; Reux, C.; Kiptily, V. G.; Pautasso, G.; Decker, J.; Papp, G.; Kallenbach, A.; Weinzettl, V.; Mlynar, J.; Coda, S.; Riccardo, V.; Lomas, P.; Jachmich, S.; Shevelev, A. E.; Alper, B.; Khilkevitch, E.; Martin, Y.; Dux, R.; Fuchs, C.; Duval, B.; Brix, M.; Tardini, G.; Maraschek, M.; Treutterer, W.; Giannone, L.; Mlynek, A.; Ficker, O.; Martin, P.; Gerasimov, S.; Potzel, S.; Paprok, R.; McCarthy, P. J.; Imrisek, M.; Boboc, A.; Lackner, K.; Fernandes, A.; Havlicek, J.; Giacomelli, L.; Vlainic, M.; Nocente, M.; Kruezi, U.; COMPASS Team; TCV Team; ASDEX-Upgrade Team; EUROFusion MST1 Team; contributors, JET

    2018-01-01

    This paper presents a survey of the experiments on runaway electrons (RE) carried out recently in frames of EUROFusion Consortium in different tokamaks: COMPASS, ASDEX-Upgrade, TCV and JET. Massive gas injection (MGI) has been used in different scenarios for RE generation in small and medium-sized tokamaks to elaborate the most efficient and reliable ones for future RE experiments. New data on RE generated at disruptions in COMPASS and ASDEX-Upgrade was collected and added to the JET database. Different accessible parameters of disruptions, such as current quench rate, conversion rate of plasma current into runaways, etc have been analysed for each tokamak and compared to JET data. It was shown, that tokamaks with larger geometrical sizes provide the wider limits for spatial and temporal variation of plasma parameters during disruptions, thus extending the parameter space for RE generation. The second part of experiments was dedicated to study of RE generation in stationary discharges in COMPASS, TCV and JET. Injection of Ne/Ar have been used to mock-up the JET MGI runaway suppression experiments. Secondary RE avalanching was identified and quantified for the first time in the TCV tokamak in RE generating discharges after massive Ne injection. Simulations of the primary RE generation and secondary avalanching dynamics in stationary discharges has demonstrated that RE current fraction created via avalanching could achieve up to 70-75% of the total plasma current in TCV. Relaxations which are reminiscent the phenomena associated to the kinetic instability driven by RE have been detected in RE discharges in TCV. Macroscopic parameters of RE dominating discharges in TCV before and after onset of the instability fit well to the empirical instability criterion, which was established in the early tokamaks and examined by results of recent numerical simulations.

  10. A new 3D viewer as an interface between the ASDEX Upgrade CAD models and data from plasma modelling and experiment

    International Nuclear Information System (INIS)

    Lunt, T.; Fuchs, J.C.; Mank, K.; Feng, Y.; Brochard, F.; Herrmann, A.; Rohde, V.; Endstrasser, N.

    2010-01-01

    A generally available and easy-to-use viewer for the simultaneous visualisation of the ASDEX Upgrade vacuum vessel computer aided design models, diagnostics and magnetic geometry, solutions of 3D plasma simulation codes and 2D camera images was developed. Here we report on the working principle of this software and give several examples of its technical and scientific application.

  11. Operation of ASDEX Upgrade with tungsten coated walls

    International Nuclear Information System (INIS)

    Rohde, V.

    2002-01-01

    An alternative for low-Z materials in the main chamber of a future fusion device are high-Z materials, but the maximal tolerable concentration in the plasma core is restricted. A step by step approach to employ tungsten at the central column of ASDEX Upgrade was started in 1999. Meanwhile almost the whole central column is covered with tiles, which were coated by PVD with tungsten. Up to now 9000 s of plasma discharge covering all relevant scenarios were performed. Routine operation of ASDEX Upgrade was not affected by the tungsten. Typical concentrations below 10 -5 were found. The tungsten concentration is mostly connected to the transport into the core plasma, not to the tungsten erosion. It can be demonstrated, that additional central heating can eliminate the tungsten accumulation. These experiments demonstrate the compatibility of fusion plasmas with W plasma facing components under reactor relevant conditions. The erosion pattern found by post mortem analysis indicates that the main effect is ion sputtering. The main erosion of tungsten seems to occur during plasma ramp-up and ramp-down. (author)

  12. Divertor radiation in the ASDEX upgrade tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Sehmer, Till; Bernert, Matthias; Koll, Juergen; Meister, Hans; Wischmeier, Marco; Fantz, Ursel [Max-Planck-Institut fuer Plasmaphysik, Boltzmannstrasse 2, 85748 Garching (Germany); Reimold, Felix [Forschungszentrum Juelich GmbH, Institut fuer Energie- und Klimaforschung - Plasmaphysik, 52425 Juelich (Germany); Collaboration: The ASDEX Upgrade Team

    2016-07-01

    To reduce in ITER the expected power flux density onto the divertor target, the plasma-wall interaction in the divertor needs to be strongly reduced. The fundamental path to achieve this is using radiation from seeded impurities, whereas the localization of this radiation (e.g. inside/outside confined region), which could have an impact onto the power balance, is a key challenge. The absolute radiated power distribution can be measured by foil bolometers. To study at the ASDEX Upgrade tungsten divertor the localization and quantification of radiation, the respective line of sight density of the bolometers has been improved by two additional cameras. The divertor radiation enhanced by nitrogen (N{sub 2}) seeding has been investigated, using variations of (1) the external heating power or (2) the N{sub 2} seeding rate. While in both cases the inner divertor stays fully detached, measurements indicate that the region of dominant radiation moves from the inner divertor through the X-Point into the confined region. In the outer divertor however, the measurements indicate either an immediate upwards shift or a continuous movement of the radiation away from the target, depending on experimental conditions.

  13. Stochastic sawtooth reconnection in ASDEX Upgrade

    International Nuclear Information System (INIS)

    Igochine, V.; Dumbrajs, O.; Zohm, H.; Flaws, A.

    2007-01-01

    In this paper we investigate non-complete sawtooth reconnection in the ASDEX Upgrade tokamak. Such reconnection phenomena are associated with internal m/n = 1/1 kink mode which does not vanish after the crash phase (as would be the case for complete reconnection). It is shown that this sawtooth cannot be fully described by pure m/n = 1/1 mode and that higher harmonics play an important role during the sawtooth crash phase. We employ the Hamiltonian formalism and reconstructed perturbations to model incomplete sawtooth reconnection. It is demonstrated that stochastization appears due to the excitation of low-order resonances which are present in the corresponding q-profiles inside the q = 1 surface which reflects the key role of the q 0 value. Depending on this value two completely different situations are possible for one and the same mode perturbations: (i) the resonant surfaces are present in the q-profile leading to stochasticity and sawtooth crash (q 0 ∼ 0.7 ± 0.1); (ii) the resonant surfaces are not present, which means no stochasticity in the system and no crash event (q 0 ∼ 0.9 ± 0.05). Accordingly the central safety factor value is always less than unity in the case of a non-complete sawtooth reconnection. Our investigations show that the stochastic model agrees well with the experimental observations and can be proposed as a promising candidate for an explanation of the sawtooth reconnection

  14. Improvements in disruption prediction at ASDEX Upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Aledda, R., E-mail: raffaele.aledda@diee.unica.it; Cannas, B., E-mail: cannas@diee.unica.it; Fanni, A., E-mail: fanni@diee.unica.it; Pau, A., E-mail: alessandro.pau@diee.unica.it; Sias, G., E-mail: giuliana.sias@diee.unica.it

    2015-10-15

    Highlights: • A disruption prediction system for AUG, based on a logistic model, is designed. • The length of the disruptive phase is set for each disruption in the training set. • The model is tested on dataset different from that used during the training phase. • The generalization capability and the aging of the model have been tested. • The predictor performance is compared with the locked mode detector. - Abstract: In large-scale tokamaks disruptions have the potential to create serious damage to the facility. Hence disruptions must be avoided, but, when a disruption is unavoidable, minimizing its severity is mandatory. A reliable detection of a disruptive event is required to trigger proper mitigation actions. To this purpose machine learning methods have been widely studied to design disruption prediction systems at ASDEX Upgrade. The training phase of the proposed approaches is based on the availability of disrupted and non-disrupted discharges. In literature disruptive configurations were assumed appearing into the last 45 ms of each disruption. Even if the achieved results in terms of correct predictions were good, it has to be highlighted that the choice of such a fixed temporal window might have limited the prediction performance. In fact, it generates confusing information in cases of disruptions with disruptive phase different from 45 ms. The assessment of a specific disruptive phase for each disruptive discharge represents a relevant issue in understanding the disruptive events. In this paper, the Mahalanobis distance is applied to define a specific disruptive phase for each disruption, and a logistic regressor has been trained as disruption predictor. The results show that enhancements on the achieved performance on disruption prediction are possible by defining a specific disruptive phase for each disruption.

  15. Improvements in disruption prediction at ASDEX Upgrade

    International Nuclear Information System (INIS)

    Aledda, R.; Cannas, B.; Fanni, A.; Pau, A.; Sias, G.

    2015-01-01

    Highlights: • A disruption prediction system for AUG, based on a logistic model, is designed. • The length of the disruptive phase is set for each disruption in the training set. • The model is tested on dataset different from that used during the training phase. • The generalization capability and the aging of the model have been tested. • The predictor performance is compared with the locked mode detector. - Abstract: In large-scale tokamaks disruptions have the potential to create serious damage to the facility. Hence disruptions must be avoided, but, when a disruption is unavoidable, minimizing its severity is mandatory. A reliable detection of a disruptive event is required to trigger proper mitigation actions. To this purpose machine learning methods have been widely studied to design disruption prediction systems at ASDEX Upgrade. The training phase of the proposed approaches is based on the availability of disrupted and non-disrupted discharges. In literature disruptive configurations were assumed appearing into the last 45 ms of each disruption. Even if the achieved results in terms of correct predictions were good, it has to be highlighted that the choice of such a fixed temporal window might have limited the prediction performance. In fact, it generates confusing information in cases of disruptions with disruptive phase different from 45 ms. The assessment of a specific disruptive phase for each disruptive discharge represents a relevant issue in understanding the disruptive events. In this paper, the Mahalanobis distance is applied to define a specific disruptive phase for each disruption, and a logistic regressor has been trained as disruption predictor. The results show that enhancements on the achieved performance on disruption prediction are possible by defining a specific disruptive phase for each disruption.

  16. Replacement strategy for ASDEX upgrade's new control and data acquisition

    International Nuclear Information System (INIS)

    Raupp, G.; Behler, K.; Cole, R.; Engelhardt, K.; Lohs, A.; Lueddecke, K.; Neu, G.; Treutterer, W.; Vijverberg, Th.; Zasche, D.; Zehetbauer, Th.

    2004-01-01

    ASDEX Upgrade is being equipped with a new real-time plasma control and data acquisition system and a novel time system. Major components were implemented and installed. While much work for performance optimisation and application programming remains to be done, commissioning of the new system parallel to experiment operation is being prepared. Commissioning of the new system will be done step-by-step. To facilitate testing the old and new control systems share all input signals. Switching between old and new system can be performed within 60 min: 23 fibre optics for output of actuator commands and input triggers must be connected to the active system and minor modifications done to interface the machine protection. Commissioning phases include background listening, technical discharges and full plasma operation. With the strategy chosen we minimize risk to the machine and reduce interference with ongoing experiment campaigns

  17. Amplitude based feedback control for NTM stabilisation at ASDEX Upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Rapson, Christopher, E-mail: chris.rapson@ipp.mpg.de; Giannone, Louis; Maraschek, Marc; Reich, Matthias; Stober, Joerg; Treutterer, Wolfgang

    2014-05-15

    Highlights: • Two algorithms have been developed which use the NTM amplitude to control ECCD deposition and stabilise NTMs. • Both algorithms were tested and tuned in a simulation of the full feedback loop including an MRE. • Both algorithms have been successfully deployed in ASDEX Upgrade experiments. • Use of the NTM amplitude adds considerable robustness, which is necessary when trying to target ECCD to within 1 cm of the island location. • This is part of ongoing work to reliably and quickly stabilise NTMs in any plasma scenario. - Abstract: Neoclassical Tearing Modes (NTMs) degrade the confinement in tokamak plasmas at high beta, placing a major limitation on the projected fusion performance. Furthermore, NTMs can lead to disruptions with even more severe consequences. Therefore methods to stabilise NTMs are being developed with high priority at several research institutes worldwide. The favoured method is to deposit Electron Cyclotron Current Drive (ECCD) precisely at the mode location by controlling a movable mirror in the ECCD launcher. This method requires both the mode location and the deposition location to be known with high accuracy in real time. The required accuracy is given by half of the marginal island width, or approximately 1 cm for a m/n = 3/2 NTM at ASDEX Upgrade. Despite considerable development on a range of diagnostics, it remains challenging to provide the necessary accuracy reliably and in real time. To relax the accuracy requirements and add robustness, the feedback controller can additionally consider the effect of ECCD on the NTM amplitude directly. Then the optimal deposition location is simply where the NTM amplitude is minimised. The simplest implementation sweeps the ECCD beam across the expected NTM location. After the sweep, the beam can be returned to the optimal location and held there to stabilise the NTM. Unfortunately, waiting for a full sweep takes too long. Therefore a second method assesses the NTM growth every

  18. Turbulence in high-beta ASDEX upgrade advanced scenarios

    Science.gov (United States)

    Doerk, H.; Bock, A.; Di Siena, A.; Fable, E.; Görler, T.; Jenko, F.; Stober, J.; The ASDEX Upgrade Team

    2018-01-01

    Recent experiments at ASDEX Upgrade achieve non-inductive operation in full tungsten wall conditions by applying electron cyclotron and neutral beam current drive. These discharges are characterised by a well-measured safety factor profile, which does not drop below one, and a good energy confinement. By reproducing the experimental heat fluxes, nonlinear gyrokinetic simulations suggest that the observed strong peaking of the ion temperature in the core is caused by the stabilising impact of a significant beam ion content, as well as strong electromagnetic effects on turbulent transport. Quasilinear transport models are not yet applicable in this interesting and reactor relevant parameter regime, but available simulation data may serve as a testbed for improvements. As the present plasma is close to the kinetic ballooning (KBM) threshold, elevating the safety factor profile under otherwise identical conditions is proposed to clarify, whether profiles are ultimately limited by KBM turbulence, or by global stability constraints.

  19. Real time capable infrared thermography for ASDEX Upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Sieglin, B., E-mail: Bernhard.Sieglin@ipp.mpg.de; Faitsch, M.; Herrmann, A.; Brucker, B.; Eich, T.; Kammerloher, L.; Martinov, S. [Max-Planck Institute for Plasma Physics, Boltzmannstr. 2, D-85748 Garching (Germany)

    2015-11-15

    Infrared (IR) thermography is widely used in fusion research to study power exhaust and incident heat load onto the plasma facing components. Due to the short pulse duration of today’s fusion experiments, IR systems have mostly been designed for off-line data analysis. For future long pulse devices (e.g., Wendelstein 7-X, ITER), a real time evaluation of the target temperature and heat flux is mandatory. This paper shows the development of a real time capable IR system for ASDEX Upgrade. A compact IR camera has been designed incorporating the necessary magnetic and electric shielding for the detector, cooler assembly. The camera communication is based on the Camera Link industry standard. The data acquisition hardware is based on National Instruments hardware, consisting of a PXIe chassis inside and a fibre optical connected industry computer outside the torus hall. Image processing and data evaluation are performed using real time LabVIEW.

  20. ICRF induced edge plasma convection in ASDEX upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Wei [Max Planck Institute for Plasma Physics, Garching/Greifswald (Germany); University of Ghent, Ghent (Belgium); Institute of Plasma Physics, Chinese Academy of Sciences, Hefei (China); Feng, Yuehe; Lunt, Tilmann; Jacquot, Jonathan; Coster, David; Bilato, Roberto; Bobkov, Volodymyr; Ochoukov, Roman [Max Planck Institute for Plasma Physics, Garching/Greifswald (Germany); Noterdaeme, Jean-Marie [Max Planck Institute for Plasma Physics, Garching/Greifswald (Germany); University of Ghent, Ghent (Belgium); Colas, Laurent [CEA, IRFM, Saint-Paul-Lez-Durance (France); Collaboration: ASDEX Upgrade Team

    2016-07-01

    Ion Cyclotron Range of Frequency (ICRF) heating is one of the main auxiliary plasma heating methods in tokamaks. It relies on the fast wave to heat the plasma. However the slow wave can also be generated parasitically. The parallel electric field of the slow wave can induce large biased plasma potential through sheath rectification. The rapid variation of this rectified potential across the magnetic field can cause significant E x B convection in the Scrape-Off Layer (SOL). The ICRF induced convection can affect the SOL density, influence the ICRF power coupling and enhance the strength of plasma-wall interactions. To explore these physics, we not only show the experimental evidences in ASDEX Upgrade, but also present the associated simulation results with the 3D edge plasma fluid code EMC3-Eirene. Further simulations via combination of EMC3-Eirene and a sheath code SSWICH in an iterative and quasi self-consistent way can give good predictions for future experiments.

  1. Comparison of fast ion collective Thomson scattering measurements at ASDEX Upgrade with numerical simulations

    DEFF Research Database (Denmark)

    Salewski, Mirko; Meo, Fernando; Stejner Pedersen, Morten

    2010-01-01

    Collective Thomson scattering (CTS) experiments were carried out at ASDEX Upgrade to measure the one-dimensional velocity distribution functions of fast ion populations. These measurements are compared with simulations using the codes TRANSP/NUBEAM and ASCOT for two different neutral beam injecti...

  2. Status of the new multi-frequency ECRH system for ASDEX Upgrade

    DEFF Research Database (Denmark)

    Wagner, D.; Grünwald, G.; Leuterer, F.

    2008-01-01

    Currently, a new multi-frequency ECRH system is under construction at the ASDEX Upgrade tokamak experiment. This system employs, for the first time in a fusion device, multi-frequency gyrotrons, step-tunable in the range 105-140 GHz. The first two gyrotrons, working at 105 and 140 GHz, were...

  3. Sensitivity study of a proposed polarimetry diagnostic on ASDEX upgrade

    International Nuclear Information System (INIS)

    Callaghan, H.P.; McCarthy, P.J.

    1994-09-01

    ASDEX-Upgrade currently uses FIR interferometry (DCN, 195 μm) as a technique for measuring line integrated electron density along eight chords of the plasma cross-section. A polarimetry diagnostic based on Faraday rotation using the existing setup would yield ∫ n e B.dl along the same chords which, in combination with the ∫ n e dl measurements, would provide additional information about the poloidal magnetic field. This would be helpful for reconstructing the q(ψ) profile, which is difficult to recover from external magnetic measurements alone. A sensitivity study to determine the effectiveness of adding polarimetry to ASDEX Upgrade is carried out using function parameterization on a simulated equilibrium database, together with a database of randomly chosen density profiles with four degrees of freedom. The robustness of the recovery in the presence of measurement noise and the effects of plasma birefringence are taken into account. (orig.)

  4. Electron heat transport studies using transient phenomena in ASDEX Upgrade

    International Nuclear Information System (INIS)

    Jacchia, A.; Angioni, C.; Manini, A.; Ryter, F.; Apostoliceanu, M.; Conway, G.; Fahrbach, H.-U.; Kirov, K.K.; Leuterer, F.; Reich, M.; Sutttrop, W.; Cirant, S.; Mantica, P.; De Luca, F.; Weiland, J.

    2005-01-01

    Experiments in tokamaks suggest that a critical gradient length may cause the resilient behavior of T e profiles, in the absence of ITBs. This agrees in general with ITG/TEM turbulence physics. Experiments in ASDEX Upgrade using modulation techniques with ECH and/or cold pulses demonstrate the existence of a threshold in R/L Te when T e >T i and T e ≤T i . For T e >T i linear stability analyses indicate that electron heat transport is dominated by TEM modes. They agree in the value of the threshold (both T e and n e ) and for the electron heat transport increase above the threshold. The stabilization of TEM modes by collisions yielded by gyro-kinetic calculations, which suggests a transition from TEM to ITG dominated transport at high collisionality, is experimentally demonstrated by comparing heat pulse and steady-state diffusivities. For the T e ∼T i discharges above the threshold the resilience, normalized by T e 3/2 , is similar to that of the TEM dominated cases, despite very different conditions. The heat pinch predicted by fluid modeling of ITG/TEM turbulence is investigated by perturbative transport in off-axis ECH-heated discharges. (author)

  5. Multivariate statistical models for disruption prediction at ASDEX Upgrade

    International Nuclear Information System (INIS)

    Aledda, R.; Cannas, B.; Fanni, A.; Sias, G.; Pautasso, G.

    2013-01-01

    In this paper, a disruption prediction system for ASDEX Upgrade has been proposed that does not require disruption terminated experiments to be implemented. The system consists of a data-based model, which is built using only few input signals coming from successfully terminated pulses. A fault detection and isolation approach has been used, where the prediction is based on the analysis of the residuals of an auto regressive exogenous input model. The prediction performance of the proposed system is encouraging when it is applied to the same set of campaigns used to implement the model. However, the false alarms significantly increase when we tested the system on discharges coming from experimental campaigns temporally far from those used to train the model. This is due to the well know aging effect inherent in the data-based models. The main advantage of the proposed method, with respect to other data-based approaches in literature, is that it does not need data on experiments terminated with a disruption, as it uses a normal operating conditions model. This is a big advantage in the prospective of a prediction system for ITER, where a limited number of disruptions can be allowed

  6. Power inverter design for ASDEX Upgrade saddle coils

    Energy Technology Data Exchange (ETDEWEB)

    Teschke, M., E-mail: teschke@ipp.mpg.de [Max Planck Institute for Plasma Physics, EURATOM Association, Boltzmannstr. 2, 85748 Garching (Germany); Suttrop, W.; Rott, M. [Max Planck Institute for Plasma Physics, EURATOM Association, Boltzmannstr. 2, 85748 Garching (Germany)

    2013-10-15

    Highlights: ► A cost effective inverter topology for AUG's 16 in-vessel saddle coils has been found. ► Use of commercially available power modules is possible. ► Exchange of reactive power between multiple inverters is possible. ► Influence of electromagnetic noise to AUG's diagnostics was measured. ► Gas insulation of electric feed through significantly depends on magnetic fields. It is protected by fast turn-off circuit. -- Abstract: A set of 16 in-vessel saddle coils has been installed in the ASDEX Upgrade (AUG) experiment since the end of 2011 [1]. To achieve full performance, it is necessary to operate them with alternating current (AC) of arbitrary waveforms. To generate spatially resolved magnetic fields, it is required to allocate separate power inverters to every single coil. Therefore, different topologies are analyzed and compared. Studies of the commutation behavior of power stages, different pulse width modulation (PWM) schemes and single-phase-to-earth fault detection are executed. Experiments to evaluate the electromagnetic interference (EMI) of possible inverter topologies on the AUG diagnostics are done as well. A special focus is put on the feasibility of analyzed topologies using industrially available and fully assembled “power modules” to minimize development effort and costs.

  7. Update on the ASDEX Upgrade data acquisition and data management environment

    Energy Technology Data Exchange (ETDEWEB)

    Behler, K., E-mail: karl.behler@ipp.mpg.de; Blank, H.; Buhler, A.; Drube, R.; Eixenberger, H.; Engelhardt, K.; Lohs, A.; Merkel, R.; Raupp, G.; Treutterer, W.

    2014-05-15

    Highlights: • An exponential growth of data amount was managed over more than twenty years of experiment operation. • Continuous adaptation of the diagnostic software and configuration keeps track with actual experiment demands. • A great number of distributed, varying diagnostics is centrally managed. - Abstract: It has been a while since it had been reported on the status of ASDEX Upgrade data acquisition (DAQ) and data management environment. An update on changes, expansions, and enhancements applied in the last years will be given. The acquired amount of data per shot increased from 4 GiB to 40 GiB in eight years. Network, storage, and archive challenges have been managed by stepwise improvements. New DAQ techniques have been introduced to replace outdated technologies. Real-time diagnostics speed-up data provisioning and contribute to feedback control. Information technology applied to ASDEX Upgrade is under permanent change. Recent and future steps are outlined.

  8. Impurity seeding in ASDEX upgrade tokamak modeled by COREDIV code

    Energy Technology Data Exchange (ETDEWEB)

    Galazka, K.; Ivanova-Stanik, I.; Czarnecka, A.; Zagoerski, R. [Institute of Plasma Physics and Laser Microfusion, Warsaw (Poland); Bernert, M.; Kallenbach, A. [Max-Planck-Institut fuer Plasmaphysik, Garching (Germany); Collaboration: ASDEX Upgrade Team

    2016-08-15

    The self-consistent COREDIV code is used to simulate discharges in a tokamak plasma, especially the influence of impurities during nitrogen and argon seeding on the key plasma parameters. The calculations are performed with and without taking into account the W prompt redeposition in the divertor area and are compared to the experimental results acquired on ASDEX Upgrade tokamak (shots 29254 and 29257). For both impurities the modeling shows a better agreement with the experiment in the case without prompt redeposition. It is attributed to higher average tungsten concentration, which on the other hand seriously exceeds the experimental value. By turning the prompt redeposition process on, the W concentration is lowered, what, in turn, results in underestimation of the radiative power losses. By analyzing the influence of the transport coefficients on the radiative power loss and average W concentration it is concluded that the way to compromise the opposing tendencies is to include the edge-localized mode flushing mechanism into the code, which dominates the experimental particle and energy balance. Also performing the calculations with both anomalous and neoclassical diffusion transport mechanisms included is suggested. (copyright 2016 The Authors. Contributions to Plasma Physics published by Wiley-VCH Verlag GmbH and Co. KGaA Weinheim. This)

  9. The ASDEX upgrade toroidal field magnet and poloidal divertor field coil system adapted to reactor requirements

    International Nuclear Information System (INIS)

    Koeppendoerfer, W.; Blaumoser, M.; Ennen, K.; Gruber, J.; Gruber, O.; Jandl, O.; Kaufmann, M.; Kollotzek, H.; Kotzlowski, H.; Lackner, E.; Lackner, K.; Larcher, T. von; Noterdaeme, J.M.; Pillsticker, M.; Poehlchen, R.; Preis, H.; Schneider, H.; Seidel, U.; Sombach, B.; Speth, E.; Streibl, B.; Vernickel, H.; Werner, F.; Wesner, F.; Wieczorek, A.

    1986-01-01

    ASDEX Upgrade is a tokamak experiment with external poloidal field coils that is now under construction at IPP Garching. It can produce elongated single-null (SN), double-null (DN) , and limiter (L) configurations. The SN is the reference configuration with asymmetric load distributions in the poloidal field (PF) system and the toroidal field (TF) magnet. Plasma control and stabilization require a rigid passive conductor close to the plasma. The design principles of the coils and support structure are described. (orig.)

  10. Measuring main-ion temperatures in ASDEX upgrade using scattering of ECRH radiation

    DEFF Research Database (Denmark)

    Pedersen, Morten Stejner; Nielsen, Stefan Kragh; Jacobsen, Asger Schou

    2016-01-01

    We demonstrate that collective Thomson scattering of millimeter wave electron cyclotron resonance heating radiation can be used for measurements of the main-ion temperature in the ASDEX Upgrade tokamak.......We demonstrate that collective Thomson scattering of millimeter wave electron cyclotron resonance heating radiation can be used for measurements of the main-ion temperature in the ASDEX Upgrade tokamak....

  11. Energy and particle control characteristics of the ASDEX Upgrade 'LYRA' divertor

    International Nuclear Information System (INIS)

    Kaufmann, M.; Bosch, H.S.; Herrmann, A.

    1999-01-01

    In 1997 the new 'LYRA' divertor went into operation at ASDEX Upgrade and the neutral beam heating power was increased to 20 MW by installation of a second injector. This leads to the relatively high value of P/R of 12 MW/m. It has been shown that the ASDEX Upgrade LYRA divertor is capable of handling such high heating powers. Measurements presented in this paper reveal a reduction of the maximum heat flux in the LYRA divertor by more than a factor of two compared to the open Divertor I. This reduction is caused by radiative losses inside the divertor region. Carbon radiation cools the divertor plasma down to a few eV where hydrogen radiation losses become significant. They are increased due to an effective reflection of neutrals into the hot separatrix region. B2-Eirene modelling of the performed experiments supports the experimental findings and refines the understanding of loss processes in the divertor region. (author)

  12. Energy and particle control characteristics of the ASDEX Upgrade 'LYRA' divertor

    International Nuclear Information System (INIS)

    Kaufmann, M.; Bosch, H.-S.; Herrmann, A.

    2001-01-01

    In 1997 the new 'LYRA' divertor went into operation at ASDEX Upgrade and the neutral beam heating power was increased to 20 MW by installation of a second injector. This leads to the relatively high value of P/R of 12 MW/m. It has been shown that the ASDEX Upgrade LYRA divertor is capable of handling such high heating powers. Measurements presented in this paper reveal a reduction of the maximum heat flux in the LYRA divertor by more than a factor of two compared to the open Divertor I. This reduction is caused by radiative losses inside the divertor region. Carbon radiation cools the divertor plasma down to a few eV where hydrogen radiation losses become significant. They are increased due to an effective reflection of neutrals into the hot separatrix region. B2-Eirene modelling of the performed experiments supports the experimental findings and refines the understanding of loss processes in the divertor region. (and others)

  13. The ASDEX upgrade digital video processing system for real-time machine protection

    Energy Technology Data Exchange (ETDEWEB)

    Drube, Reinhard, E-mail: reinhard.drube@ipp.mpg.de [Max-Planck-Institut für Plasmaphysik, EURATOM Association, Boltzmannstr. 2, 85748 Garching (Germany); Neu, Gregor [Max-Planck-Institut für Plasmaphysik, EURATOM Association, Boltzmannstr. 2, 85748 Garching (Germany); Cole, Richard H.; Lüddecke, Klaus [Unlimited Computer Systems GmbH, Seeshaupterstr. 15, 82393 Iffeldorf (Germany); Lunt, Tilmann; Herrmann, Albrecht [Max-Planck-Institut für Plasmaphysik, EURATOM Association, Boltzmannstr. 2, 85748 Garching (Germany)

    2013-11-15

    Highlights: • We present the Real-Time Video diagnostic system of ASDEX Upgrade. • We show the implemented image processing algorithms for machine protection. • The way to achieve a robust operating multi-threading Real-Time system is described. -- Abstract: This paper describes the design, implementation, and operation of the Video Real-Time (VRT) diagnostic system of the ASDEX Upgrade plasma experiment and its integration with the ASDEX Upgrade Discharge Control System (DCS). Hot spots produced by heating systems erroneously or accidentally hitting the vessel walls, or from objects in the vessel reaching into the plasma outer border, show up as bright areas in the videos during and after the reaction. A system to prevent damage to the machine by allowing for intervention in a running discharge of the experiment was proposed and implemented. The VRT was implemented on a multi-core real-time Linux system. Up to 16 analog video channels (color and b/w) are acquired and multiple regions of interest (ROI) are processed on each video frame. Detected critical states can be used to initiate appropriate reactions – e.g. gracefully terminate the discharge. The system has been in routine operation since 2007.

  14. H-mode and confinement studies in ASDEX Upgrade

    International Nuclear Information System (INIS)

    Suttrop, W.; Ryter, F.; Mertens, V.; Gruber, O.; Murmann, H.; Salzmann, H.; Schweinzer, J.

    2001-01-01

    H-mode operational boundaries and H-mode confinement are investigated on ASDEX Upgrade. The local edge parameter threshold for H-mode holds independent of divertor geometry and changes little with ion mass. The deviation of the H-mode power threshold at densities near the Greenwald limit can be understood as a consequence of a confinement deterioration, caused by 'stiff' temperature profiles and lack of core density gradients in gas puff fuelled discharges. Ion and electron temperature profiles can be described by a lower limit of gradient length L T =T/T'. (author)

  15. Recent results of reflectometry on ASDEX-upgrade

    International Nuclear Information System (INIS)

    Manso, M.; Serra, F.; Numes, I.; Cupido, L.; Grossmann, V.; Meneses, L.; Santos, J.; Silva, A.; Silva, F.; Varela, P.; Vergamota, S.; Maraschek, M.

    1999-01-01

    Reflectometry is well known to be very sensitive to plasma density fluctuations. The study of plasma response in broadband frequency operation is concentrated on the obtention of the main peak and many techniques have been developed to filter the unwanted components. In comparison little work has been done to understand the remaining part of the signal. This paper presents some recent results about plasma fluctuations obtained with FM-reflectometry on ASDEX-Upgrade. They demonstrate the rich content information of both the fixed frequency and broadband signals and suggest that they can be used in a complementary way. (A.L.B.)

  16. Imaging motional Stark effect measurements at ASDEX Upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Ford, O. P.; Burckhart, A.; McDermott, R.; Pütterich, T.; Wolf, R. C. [Max-Planck Institut für Plasmaphysik, Greifswald/Garching (Germany)

    2016-11-15

    This paper presents an overview of results from the Imaging Motional Stark Effect (IMSE) diagnostic obtained during its first measurement campaign at ASDEX Upgrade since installation as a permanent diagnostic. A brief overview of the IMSE technique is given, followed by measurements of a standard H-mode discharge, which are compared to equilibrium reconstructions showing good agreement where expected. The development of special discharges for the calibration of pitch angle is reported and safety factor profile changes during sawteeth crashes are shown, which can be resolved to a few percent due to the high sensitivity at good time resolution of the new IMSE system.

  17. Transforming the ASDEX Upgrade discharge control system to a general-purpose plasma control platform

    International Nuclear Information System (INIS)

    Treutterer, Wolfgang; Cole, Richard; Gräter, Alexander; Lüddecke, Klaus; Neu, Gregor; Rapson, Christopher; Raupp, Gerhard; Zasche, Dieter; Zehetbauer, Thomas

    2015-01-01

    Highlights: • Control framework split in core and custom part. • Core framework deployable in other fusion device environments. • Adaptible through customizable modules, plug-in support and generic interfaces. - Abstract: The ASDEX Upgrade Discharge Control System DCS is a modern and mature product, originally designed to regulate and supervise ASDEX Upgrade Tokamak plasma operation. In its core DCS is based on a generic, versatile real-time software framework with a plugin architecture that allows to easily combine, modify and extend control function modules in order to tailor the system to required features and let it continuously evolve with the progress of an experimental fusion device. Due to these properties other fusion experiments like the WEST project have expressed interest in adopting DCS. For this purpose, essential parts of DCS must be unpinned from the ASDEX Upgrade environment by exposure or introduction of generalised interfaces. Re-organisation of DCS modules allows distinguishing between intrinsic framework core functions and device-specific applications. In particular, DCS must be prepared for deployment in different system environments with their own realisations for user interface, pulse schedule preparation, parameter server, time and event distribution, diagnostic and actuator systems, network communication and data archiving. The article explains the principles of the revised DCS structure, derives the necessary interface definitions and describes major steps to achieve the separation between general-purpose framework and fusion device specific components.

  18. Transforming the ASDEX Upgrade discharge control system to a general-purpose plasma control platform

    Energy Technology Data Exchange (ETDEWEB)

    Treutterer, Wolfgang, E-mail: Wolfgang.Treutterer@ipp.mpg.de [Max-Planck-Institut für Plasmaphysik, Boltzmannstr. 2, 85748 Garching (Germany); Cole, Richard [Unlimited Computer Systems, Seeshaupter Str. 15, 82393 Iffeldorf (Germany); Gräter, Alexander [Max-Planck-Institut für Plasmaphysik, Boltzmannstr. 2, 85748 Garching (Germany); Lüddecke, Klaus [Unlimited Computer Systems, Seeshaupter Str. 15, 82393 Iffeldorf (Germany); Neu, Gregor; Rapson, Christopher; Raupp, Gerhard; Zasche, Dieter; Zehetbauer, Thomas [Max-Planck-Institut für Plasmaphysik, Boltzmannstr. 2, 85748 Garching (Germany)

    2015-10-15

    Highlights: • Control framework split in core and custom part. • Core framework deployable in other fusion device environments. • Adaptible through customizable modules, plug-in support and generic interfaces. - Abstract: The ASDEX Upgrade Discharge Control System DCS is a modern and mature product, originally designed to regulate and supervise ASDEX Upgrade Tokamak plasma operation. In its core DCS is based on a generic, versatile real-time software framework with a plugin architecture that allows to easily combine, modify and extend control function modules in order to tailor the system to required features and let it continuously evolve with the progress of an experimental fusion device. Due to these properties other fusion experiments like the WEST project have expressed interest in adopting DCS. For this purpose, essential parts of DCS must be unpinned from the ASDEX Upgrade environment by exposure or introduction of generalised interfaces. Re-organisation of DCS modules allows distinguishing between intrinsic framework core functions and device-specific applications. In particular, DCS must be prepared for deployment in different system environments with their own realisations for user interface, pulse schedule preparation, parameter server, time and event distribution, diagnostic and actuator systems, network communication and data archiving. The article explains the principles of the revised DCS structure, derives the necessary interface definitions and describes major steps to achieve the separation between general-purpose framework and fusion device specific components.

  19. Real-time signal communication between diagnostic and control in ASDEX Upgrade

    International Nuclear Information System (INIS)

    Treutterer, Wolfgang; Neu, Gregor; Raupp, Gerhard; Zehetbauer, Thomas; Zasche, Dieter; Lueddecke, Klaus; Cole, Richard

    2010-01-01

    The ASDEX Upgrade tokamak experiment is equipped with a versatile discharge monitoring and control system. It allows to develop and use advanced control algorithms to investigate plasma physics under well-defined conditions with the objective of optimising plasma performance. The achievable quality depends on the accuracy with which the plasma state can be reconstructed from measurements under real-time conditions. Today's advanced algorithms need physics quantities - scalar entities as well as profiles. These are obtained processing huge numbers of raw measurements with complex diagnostic algorithms. Adequate network communication for the resulting signals is crucial to satisfy real-time requirements, especially when several diagnostic systems cooperate in a feedback control loop. Support for the technology of choice, however, is not easily available for all of the diverse, highly specialised diagnostic systems. We give an overview about the methods that have been explored at ASDEX Upgrade for real-time signal transfer. In particular, we investigated reflective shared memory and Ethernet technologies. Our solution strives to combine their strengths. For fast communication on dedicated computing nodes, reflective shared memory is used. For the majority of diagnostic systems producing large data blocks at moderate rates, Ethernet connections with UDP protocol are employed. Following ASDEX Upgrade's framework concept, a software layer hides the networks used from both diagnostic and control applications.

  20. Real-time signal communication between diagnostic and control in ASDEX Upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Treutterer, Wolfgang, E-mail: Wolfgang.Treutterer@ipp.mpg.d [Max-Planck Institut fuer Plasmaphysik, Garching, EURATOM Association (Germany); Neu, Gregor; Raupp, Gerhard; Zehetbauer, Thomas; Zasche, Dieter [Max-Planck Institut fuer Plasmaphysik, Garching, EURATOM Association (Germany); Lueddecke, Klaus; Cole, Richard [Unlimited Computer Systems, Iffeldorf (Germany)

    2010-07-15

    The ASDEX Upgrade tokamak experiment is equipped with a versatile discharge monitoring and control system. It allows to develop and use advanced control algorithms to investigate plasma physics under well-defined conditions with the objective of optimising plasma performance. The achievable quality depends on the accuracy with which the plasma state can be reconstructed from measurements under real-time conditions. Today's advanced algorithms need physics quantities - scalar entities as well as profiles. These are obtained processing huge numbers of raw measurements with complex diagnostic algorithms. Adequate network communication for the resulting signals is crucial to satisfy real-time requirements, especially when several diagnostic systems cooperate in a feedback control loop. Support for the technology of choice, however, is not easily available for all of the diverse, highly specialised diagnostic systems. We give an overview about the methods that have been explored at ASDEX Upgrade for real-time signal transfer. In particular, we investigated reflective shared memory and Ethernet technologies. Our solution strives to combine their strengths. For fast communication on dedicated computing nodes, reflective shared memory is used. For the majority of diagnostic systems producing large data blocks at moderate rates, Ethernet connections with UDP protocol are employed. Following ASDEX Upgrade's framework concept, a software layer hides the networks used from both diagnostic and control applications.

  1. Control processes and machine protection on ASDEX Upgrade

    International Nuclear Information System (INIS)

    Raupp, G.; Treutterer, W.; Mertens, V.; Neu, G.; Sips, A.; Zasche, D.; Zehetbauer, Th.

    2007-01-01

    Safe operation of ASDEX Upgrade is guaranteed by a conventional hierarchy of simple and robust hard-wired systems for personnel and machine protection featuring standardized switch-off procedures. Machine protection and handling of off-normal events is further enhanced and peak and lifetime stress minimized through the plasma control system. Based on a real-time process model supporting safety critical applications with data quality tagging, process self-monitoring, watchdog monitoring and alarm propagation, processes detect complex and critical failures and reliably perform case-sensitive counter measures. Intelligent real-time failure handling is done with hardware or software redundancy and performance degradation, or modification of reference values to continue or terminate discharges with reduced machine stress. Examples implemented so far on ASDEX Upgrade are given, such as recovery from measurement failures, switch-over of redundant actuators, handling of actuator limitations, detection of plasma instabilities, plasma state dependent soft landing, or handling of failed switch-off procedures through breakers disconnecting the machine from grid

  2. Contribution of ASDEX Upgrade to disruption studies for ITER

    International Nuclear Information System (INIS)

    Pautasso, G.; Reiter, B.; Giannone, L.; Gruber, O.; Herrmann, A.; Kardaun, O.; Maraschek, M.; Mlynek, A.; Schneider, W.; Zhang, Y.; Khayrutdinov, K.K.; Lukash, V.E.; Nakamura, Y.; Sias, G.; Sugihara, M.

    2011-01-01

    This paper describes the most recent contributions of ASDEX Upgrade to ITER in the field of disruption studies. (1) The ITER specifications for the halo current magnitude are based on data collected from several tokamaks and summarized in the plot of the toroidal peaking factor versus the maximum halo current fraction. Even if the maximum halo current in ASDEX Upgrade reaches 50% of the plasma current, the duration of this maximum lasts a fraction of a ms. (2) Long-lasting asymmetries of the halo current are rare and do not give rise to a large asymmetric component of the mechanical forces on the machine. Differently from JET, these asymmetries are neither locked nor exhibit a stationary harmonic structure. (3) Recent work on disruption prediction has concentrated on the search for a simple function of the most relevant plasma parameters, which is able to discriminate between the safe and pre-disruption phases of a discharge. For this purpose, the disruptions of the last four years have been classified into groups and then discriminant analysis is used to select the most significant variables and to derive the discriminant function. (4) The attainment of the critical density for the collisional suppression of the runaway electrons seems to be technically and physically possible on our medium size tokamak. The CO 2 interferometer and the AXUV diagnostic provide information on the highly 3D impurity transport process during the whole plasma quench.

  3. A 'Universal Time' system for ASDEX upgrade

    International Nuclear Information System (INIS)

    Raupp, Gerhard; Cole, R.; Behler, K.; Fitzek, M.; Heimann, P.; Lohs, A.; Lueddecke, K.; Neu, G.; Schacht, J.; Treutterer, W.; Zasche, D.; Zehetbauer, Th.; Zilker, M.

    2003-01-01

    For the new generation of intelligent controllers for plasma diagnostics, discharge control and long-pulse experiment control a new time system supporting steady state real-time operation has been devised. A central unit counts time at nanosecond resolution, covering more than the experiment lifetime. The broadcast time information serves local units to perform application functions such as current time readout, trigger generation and sample time measurement. Time is treated as a precisely measured quantity like other physical quantities. Tagging all detected events and sampled values with measured times as [value; time]-entities facilitates real-time data analysis, steady state protocolling and time-sorted archiving

  4. Dimensionally similar studies of confinement and H-mode transition in ASDEX Upgrade and JET

    International Nuclear Information System (INIS)

    Ryter, F.; Stober, J.; Suttrop, W.

    2001-01-01

    Joint experiments on confinement and L-H transition were performed in ASDEX Upgrade and JET. The confinement experiments suggest that the invariance principle is not always fulfilled at high density. For the L-H transition studies, the dimensionless variables taken at the plasma edge can be in general only made identical per pair, due to the condition imposed by the L-H transition. This new approach to investigate the L-H physics suggests a weak dependence of the L-H transition mechanism on collisionality. (author)

  5. Dimensionally similar studies of confinement and H-mode transition in ASDEX Upgrade and JET

    International Nuclear Information System (INIS)

    Ryter, F.; Stober, J.; Suttrop, W.

    1999-01-01

    Joint experiments on confinement and L-H transition were performed in ASDEX Upgrade and JET. The confinement experiments suggest that the invariance principle is not always fulfilled at high density. For the L-H transition studies, the dimensionless variables taken at the plasma edge can be in general only made identical per pair, due to the condition imposed by the L-H transition. This new approach to investigate the L-H physics suggests a weak dependence of the L-H transition mechanism on collisionality. (author)

  6. Real-time feedback control of the plasma density profile on ASDEX Upgrade

    International Nuclear Information System (INIS)

    Mlynek, A.; Reich, M.; Giannone, L.; Treutterer, W.; Behler, K.; Blank, H.; Buhler, A.; Cole, R.; Eixenberger, H.; Fischer, R.; Lohs, A.; Lueddecke, K.; Merkel, R.; Neu, G.; Ryter, F.; Zasche, D.

    2011-01-01

    The spatial distribution of density in a fusion experiment is of significant importance as it enters in numerous analyses and contributes to the fusion performance. The reconstruction of the density profile is therefore commonly done in offline data analysis. In this paper, we present an algorithm which allows for density profile reconstruction from the data of the submillimetre interferometer and the magnetic equilibrium in real-time. We compare the obtained results to the profiles yielded by a numerically more complex offline algorithm. Furthermore, we present recent ASDEX Upgrade experiments in which we used the real-time density profile for active feedback control of the shape of the density profile.

  7. Low frequency sawtooth precursor activity in ASDEX Upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Papp, G; Pokol, G I; Por, G; Magyarkuti, A; Lazanyi, N; Horvath, L [Department of Nuclear Techniques, Budapest University of Technology and Economics, Association EURATOM, Pf 91, H-1521 Budapest (Hungary); Igochine, V; Maraschek, M, E-mail: papp@reak.bme.h [Max-Planck-Institut fuer Plasmaphysik, Association EURATOM, D-85748 Garching (Germany)

    2011-06-15

    This paper describes the precursor activity observed in the ASDEX Upgrade tokamak before sawtooth crashes in various neutral beam heated plasmas, utilizing the soft x-ray diagnostic. In addition to the well-known (m, n) = (1,1) internal kink mode and its harmonics, a lower frequency mode is studied in detail. Power modulation of this mode is found to correlate with the power modulation of the (1, 1) kink mode in the quasistationary intervals indicating possible nonlinear interaction. Throughout the studied sawtooth crashes, the power of the lower frequency mode rose by several orders of magnitude just before the crash. In addition to its temporal behaviour, its spatial structure was estimated and the most likely value was found to be (1, 1). A possible role of this mode in the mechanism of the sawtooth crash is discussed.

  8. Ammonia production in nitrogen seeded plasma discharges in ASDEX Upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Rohde, V., E-mail: Volker.Rohde@ipp.mpg.de; Oberkofler, M.

    2015-08-15

    In present tokamaks nitrogen seeding is used to reduce the power load onto the divertor tiles. Some fraction of the seeded nitrogen reacts with hydrogen to form ammonia. The behaviour of ammonia in ASDEX Upgrade is studied by mass spectrometry. Injection without plasma shows strong absorption at the inner walls of the vessel and isotope exchange reactions. During nitrogen seeding in H-mode discharges the onset of a saturation of the nitrogen retention is observed. The residual gas consists of strongly deuterated methane and ammonia with almost equal amounts of deuterium and protium. This confirms the role of surface reactions in the ammonia formation. The results are consistent with findings in previous investigations. A numerical decomposition of mass spectra is under development and will be needed for quantitative evaluation of the results obtained.

  9. Measurement of neoclassically predicted edge current density at ASDEX Upgrade

    Science.gov (United States)

    Dunne, M. G.; McCarthy, P. J.; Wolfrum, E.; Fischer, R.; Giannone, L.; Burckhart, A.; the ASDEX Upgrade Team

    2012-12-01

    Experimental confirmation of neoclassically predicted edge current density in an ELMy H-mode plasma is presented. Current density analysis using the CLISTE equilibrium code is outlined and the rationale for accuracy of the reconstructions is explained. Sample profiles and time traces from analysis of data at ASDEX Upgrade are presented. A high time resolution is possible due to the use of an ELM-synchronization technique. Additionally, the flux-surface-averaged current density is calculated using a neoclassical approach. Results from these two separate methods are then compared and are found to validate the theoretical formula. Finally, several discharges are compared as part of a fuelling study, showing that the size and width of the edge current density peak at the low-field side can be explained by the electron density and temperature drives and their respective collisionality modifications.

  10. Measurement of neoclassically predicted edge current density at ASDEX Upgrade

    International Nuclear Information System (INIS)

    Dunne, M.G.; McCarthy, P.J.; Wolfrum, E.; Fischer, R.; Giannone, L.; Burckhart, A.

    2012-01-01

    Experimental confirmation of neoclassically predicted edge current density in an ELMy H-mode plasma is presented. Current density analysis using the CLISTE equilibrium code is outlined and the rationale for accuracy of the reconstructions is explained. Sample profiles and time traces from analysis of data at ASDEX Upgrade are presented. A high time resolution is possible due to the use of an ELM-synchronization technique. Additionally, the flux-surface-averaged current density is calculated using a neoclassical approach. Results from these two separate methods are then compared and are found to validate the theoretical formula. Finally, several discharges are compared as part of a fuelling study, showing that the size and width of the edge current density peak at the low-field side can be explained by the electron density and temperature drives and their respective collisionality modifications. (paper)

  11. Plasma surface interaction with tungsten in ASDEX Upgrade

    International Nuclear Information System (INIS)

    Dux, R.; Herrmann, A.; Kallenbach, A.; Neu, R.; Neuhauser, J.; Maier, H.; Pugno, R.; Puetterich, T.; Rohde, V.

    2005-01-01

    ASDEX Upgrade pursues the progressive increase of W coated plasma facing components. At present, the central column, the upper passive stabiliser loop, the complete upper divertor, the baffles at the lower divertor, as well as six tiles of one guard limiter at the low field side are W coated, representing about 65% of the total surface area. W erosion at these guard limiter tiles exceeds the erosion found at other main chamber components by more than one order of magnitude, and spectroscopically determined erosion yields indicate a strong contribution from fast particles. Upper single null discharges do not show an obviously increased W content compared to discharges run in the lower C based divertor

  12. Real-time disruption handling at ASDEX upgrade

    International Nuclear Information System (INIS)

    Zehetbauer, Th.; Pautasso, G.; Tichmann, C.; Egorov, S.; Lorenz, A.; Mertens, V.; Neu, G.; Raupp, G.; Treutterer, W.; Zasche, D.

    2001-01-01

    A neural network for prediction of disruptions has been developed at ASDEX Upgrade with the goal to mitigate or avoid these. The novel idea is to compute the remaining time-to-disruption to indicate the stability level of the discharge. The neural network has been specified, trained and then implemented within the real-time plasma control system. The current version of the system terminates the discharge with an impurity pellet when the computed time-to-disruption falls below a threshold of 80 ms. Routine operation shows that disruptions are recognized reliably. Vessel currents and forces are considerably reduced. The system will be enhanced to avoid disruptions with a soft landing initiated in time

  13. Disruption prediction with adaptive neural networks for ASDEX Upgrade

    International Nuclear Information System (INIS)

    Cannas, B.; Fanni, A.; Pautasso, G.; Sias, G.

    2011-01-01

    In this paper, an adaptive neural system has been built to predict the risk of disruption at ASDEX Upgrade. The system contains a Self Organizing Map, which determines the 'novelty' of the input of a Multi Layer Perceptron predictor module. The answer of the MLP predictor will be inhibited whenever a novel sample is detected. Furthermore, it is possible that the predictor produces a wrong answer although it is fed with known samples. In this case, a retraining procedure will be performed to update the MLP predictor in an incremental fashion using data coming from both the novelty detection, and from wrong predictions. In particular, a new update is performed whenever a missed alarm is triggered by the predictor. The performance of the adaptive predictor during the more recent experimental campaigns until November 2009 has been evaluated.

  14. Zeff from spectroscopic bremsstrahlung measurements at ASDEX Upgrade and JET

    International Nuclear Information System (INIS)

    Meister, H.; Fischer, R.; Horton, L.D.; Maggi, C.F.; Nishijima, D.; Giroud, C.; Zastrow, K.-D.; Zaniol, B.

    2004-01-01

    The effective ionic charge Z eff is a means to assess the impurity content of a fusion plasma. It can be derived from measurements of bremsstrahlung intensity. These have been extended at ASDEX Upgrade by the usage of the sight lines for the charge exchange recombination diagnostic. Together with a previously installed sight line array, it is now possible to routinely determine the bremsstrahlung intensity over the whole minor radius purely from spectroscopic measurements. In a tokamak where the plasma facing components are made up of various materials, this is necessary to check if measurements are contaminated by line radiation. The bremsstrahlung background of the respective spectra is determined using Bayesian probability theory, giving consistent and improved error statistics. Using the information for electron temperature and density profiles, the Z eff profile is determined by an integrated method. The same approach to assess the Z eff profile has been demonstrated to be successful also at the JET tokamak

  15. Low frequency sawtooth precursor activity in ASDEX Upgrade

    International Nuclear Information System (INIS)

    Papp, G; Pokol, G I; Por, G; Magyarkuti, A; Lazanyi, N; Horvath, L; Igochine, V; Maraschek, M

    2011-01-01

    This paper describes the precursor activity observed in the ASDEX Upgrade tokamak before sawtooth crashes in various neutral beam heated plasmas, utilizing the soft x-ray diagnostic. In addition to the well-known (m, n) = (1,1) internal kink mode and its harmonics, a lower frequency mode is studied in detail. Power modulation of this mode is found to correlate with the power modulation of the (1, 1) kink mode in the quasistationary intervals indicating possible nonlinear interaction. Throughout the studied sawtooth crashes, the power of the lower frequency mode rose by several orders of magnitude just before the crash. In addition to its temporal behaviour, its spatial structure was estimated and the most likely value was found to be (1, 1). A possible role of this mode in the mechanism of the sawtooth crash is discussed.

  16. Density profile evolution during dynamic processes in ASDEX Upgrade

    International Nuclear Information System (INIS)

    Nunes, I.; Santos, J.; Salzedas, F.; Manso, M.; Serra, F.; Conway, G.D.; Horton, L.D.; Neuhauser, J.; Suttrop, W.

    2005-01-01

    The current understanding of edge localized modes (ELMs) and the trigger of major disruptions is largely based on phenomenology. The need to better understand the processes underlying these phenomena requires high temporal and spatial resolution diagnostics. Fast diagnostics for the temperature measurements exist, such as the ECE radiometer but, for the plasma density, the existing diagnostics such as Lithium Beam and Thomson Scattering do not have the required high temporal resolution for a period long enough to characterize the entire ELM event. The microwave reflectometry system on ASDEX Upgrade has the capability to measure electron density profiles simultaneously at the low-field and high-field sides, in broadband swept ultrafast (35μs) operation with a spatial resolution of 5mm. In this paper we report on recent results on the effects of type I ELMs on density profiles and on the density pedestal width and ELM affected depth. During the ELM event, three phases are identified: precursor, collapse and recovery. The density pedestal width is found to be approximately constant for all the ELMy H-mode discharges analyzed here, except for high input power discharges, where an increase of the density pedestal width is observed. Major disruptions limit the range of parameters used in the operation of a tokamak, especially density limit disruptions, that limit the maximum usable density. Very abrupt increases of density are observed before the onset of the electron temperature profile erosion, supporting the hypothesis that this erosion is due to convection of the magnetic field. In ITER, during the long steady state flat-top phase of the discharges magnetic measurements may accumulate significant drifts. Plasma position and shape control using reflectometry is being assessed in ASDEX Upgrade for ITER like scenarios with successful results, where it is shown that position measurements from reflectometry compared to magnetic data satisfy the ITER requirements

  17. Concepts for improving the accuracy of gas balance measurement at ASDEX Upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Härtl, T., E-mail: thomas.haertl@ipp.mpg.de; Rohde, V.; Mertens, V.

    2013-10-15

    The ITER fusion reactor which is under construction will use a deuterium–tritium gas mixture for operation. A fraction of this fusion fuel remains inside of the machine due to various mechanisms. The evaluation of this retention in present fusion experiments is of crucial importance to estimate the expected tritium inventory in ITER which shall be limited due to safety considerations. At ASDEX Upgrade (AUG) sufficiently time-resolved measurements should take place to extrapolate from current 10 s discharges to the at least intended 400 s ones of ITER. To achieve this, a new measurement system has been designed that enables accuracy of better than one per cent.

  18. Characterization of the core poloidal flow at ASDEX Upgrade

    Science.gov (United States)

    Lebschy, Alexander

    2017-10-01

    An essential result from neoclassical (NC) theory is that the fluid poloidal rotation (upol) of the main ions is strongly damped by magnetic pumping and, therefore, expected to be small (theory has been found at both DIII-D and TCV. This is qualitatively consistent with the edge results from both Alcator C-Mod and ASDEX Upgrade (AUG). At AUG thanks to an upgrade of the core charge exchange recombination spectroscopy (CXRS) diagnostics, the core upol can be evaluated through the inboard-outboard asymmetry of the toroidal rotation with an accuracy of 0.5 - 1 km / s . This measurement also provides the missing ingredient to evaluate the core (E-> × B->) velocity (uE-> × B->) via the radial force balance equation. At AUG the core upol (0.35 × B-> determined from CXRS and the perpendicular velocity measured from turbulence propagation. The difference between these two quantities is the turbulent phase velocity. The gathered dataset indicates that the transition in the turbulence regime occurs after the saturation of the energy confinement time. The author thankfully acknowledges the financial support from the Helmholtz Association of German Research Centers through the Helmholtz Young Investigators Group program.

  19. A data acquisition system for real-time magnetic equilibrium reconstruction on ASDEX Upgrade and its application to NTM stabilization experiments

    Energy Technology Data Exchange (ETDEWEB)

    Giannone, L., E-mail: Louis.Giannone@ipp.mpg.de [Max Planck Institute for Plasma Physics, EURATOM Association, 85748 Garching (Germany); Reich, M.; Maraschek, M.; Poli, E.; Rapson, C.; Barrera, L.; McDermott, R.; Mlynek, A. [Max Planck Institute for Plasma Physics, EURATOM Association, 85748 Garching (Germany); Ruan, Q. [National Instruments, Austin, TX 78759-3504 (United States); Treutterer, W. [Max Planck Institute for Plasma Physics, EURATOM Association, 85748 Garching (Germany); Wenzel, L. [National Instruments, Austin, TX 78759-3504 (United States); Bock, A.; Conway, G.; Fischer, R.; Fuchs, J.C.; Lackner, K. [Max Planck Institute for Plasma Physics, EURATOM Association, 85748 Garching (Germany); McCarthy, P.J. [Department of Physics, University College Cork, Association EURATOM-DCU, Cork (Ireland); Preuss, R. [Max Planck Institute for Plasma Physics, EURATOM Association, 85748 Garching (Germany); Rampp, M. [Computing Centre (RZG) of the Max Planck Society and the Max Planck Institute for Plasma Physics, 85748 Garching (Germany); Schuhbeck, K.H. [Max Planck Institute for Plasma Physics, EURATOM Association, 85748 Garching (Germany); and others

    2013-12-15

    Highlights: • Calculation of real-time tokamak magnetic equilibrium with constraints from magnetic probes. • Parallel equilibrium calculation including the Motional Stark Effect diagnostic as additional constraints. • Feedback control of mirror for pre-emptive ECCD stabilization of neo-classical tearing modes. • Probe calibration by individual poloidal field coil currents. • Optimized parameters for poloidal field coil location, integrator gains and the location and orientation of magnetic probes. -- Abstract: The pre-emptive stabilization of a neoclassical tearing mode, NTM, requires the calculation of the tokamak magnetic equilibrium in real-time. A launcher mirror is positioned to deposit electron cyclotron current drive on the rational surface where the NTM should appear. A real-time Grad–Shafranov solver using constraints from magnetic probe, flux loop and Motional Stark Effect measurements has been developed to locate these rational surfaces and deliver this information to the mirror controller in real-time. A novel algorithm significantly reduces the number of operations required in the first and second step of the solver. Contour integrals are carried out to calculate the q profile as a function of normalized radius and the rational surfaces are found by spline interpolation. A cycle time of 0.6 ms for calculating two tokamak equilibria in parallel using four current basis functions with magnetic constraints only and using six current basis functions with magnetic and MSE constraints has been achieved. Using these tools, pre-emptive stabilization of a m/n = 3/2 NTM mode in ASDEX Upgrade could be demonstrated.

  20. New operational spaces for the electron cyclotron resonance heating at ASDEX upgrade

    International Nuclear Information System (INIS)

    Hoehnle, Hendrik Sebastian

    2012-01-01

    In this thesis, new electron cyclotron resonance heating (ECRH) scenarios were developed for an extension of the operational space at the tokamak ASDEX Upgrade in view of ITER compatibility. In the last years, the first wall material at ASDEX Upgrade was changed from graphite to tungsten, and the ECRH is needed to control the tungsten concentration in the plasma core. But, in ITER-like plasma discharges at ASDEX Upgrade, the usage of the ECRH in the typically used second harmonic extraordinary polarised mode (X2 mode) is limited. In these ITER-scenarios a small safety factor should be achieved, which implements an increase of the plasma current at ASDEX Upgrade. A higher plasma current and a high confinement lead to a raised density and for the ITER scenario to an electron density above the cutoff of the X2 mode at ASDEX Upgrade. Therefore, the X2 mode is reflected at the cutoff layer and cannot be used for central heating and the control of the tungsten concentration. One possibility to overcome this problem is to apply the third harmonic mode at reduced magnetic field. Here the cutoff is increased by 33% due to the dependence on the magnetic field. However, at the reachable plasma parameters at the reduced field the absorption of the X3 mode is incomplete (60-70 %) and the shine-trough power can destroy microwave sensitive components in ASDEX Upgrade. To solve this problem the magnetic field has to be optimized. A slightly increased magnetic field from 1.7 T to 1.8 T moves the second harmonic resonance in the region of confined plasma with high temperatures and density, so that this resonance can act as beam dump. The deposition in the plasma core is still central enough for the tungsten control ability of the ECRH. The benefit of the beam dump was verified in experiments with two different magnetic fields (1.7 T and 1.8 T). In case of the higher magnetic field, the stray radiation was reduced; simultaneously the electron temperature was increased. In addition

  1. Pellet-plasma interaction studies at ASDEX Upgrade

    International Nuclear Information System (INIS)

    Kocsis, G.; Belonohy, E.; Gal, K.; Kalvin, S.; Veres, G.; Lang, P.T.

    2005-01-01

    Pellets produced from cryogenic hydrogen isotopes are used for efficient plasma refueling. Beyond this 'classical' application, pellets pacing the frequency of Edge Localized Modes (ELMs) turned out to be a suitable technique to mitigate the power load on plasma facing components. Although pellet pacing is already integrated in the toolkit for plasma control, its underlying physics is still poorly understood. For investigations aiming to resolve where and how an ELM is triggered by the pellet imposed local perturbation precise knowledge of the ablation profile is required. This renewed and even boosted the interest to understand the interaction of pellets with the hot ambient plasma. Both the investigation of the pellet ablation and also its impact on the target plasma were highlighted. Dedicated investigations require precise information both in the space and time domain. E. g. it is necessary to determine the localization of the pellet at the moment it triggers the ELM as well as the actual imposed 3D distribution of the pellet cloud and its mass deposition profile. By these means, a spatial distribution can be mapped out for a local perturbation of the plasma sufficient to release ELMs. High resolution ablation profile and pellet path measurements at different pellet parameters (mass and velocity) could also help to understand the mechanism of the ELM triggering. Recently pellet-plasma interaction is intensively investigated both experimentally at ASDEX Upgrade tokamak and theoretically based on the obtained experimental data. To gain detailed information an observation system was developed at ASDEX Upgrade consisting of digital cameras that detect the pellet cloud distribution and photo diodes that measure the time evolution of the light emission. The great variety of possible combinations of different images, timings and wavelength selections makes the detection sophisticated. Combination of triggered fast camera images and photo diode signals also enables us

  2. Scrape-off layer radiation and heat load to the ASDEX Upgrade LYRA divertor

    International Nuclear Information System (INIS)

    Kallenbach, A.; Kaufmann, M.; Coster, D.P.

    1999-01-01

    In 1997 the new 'LYRA' divertor went into operation at ASDEX Upgrade and, in parallel, the neutral beam heating power was increased to 20 MW by installation of a second injector leading to a P/R value of 12 MW/m. Experiments have shown that the ASDEX Upgrade LYRA divertor is capable of handling such high heating powers. There is an overall reduction of the maximum heat flux in the LYRA divertor by about a factor of 2 compared with the previous open divertor Div I. This reduction is mainly due to increased radiative losses inside the divertor region, which are caused by an effective reflection of hydrogen neutrals into the hot separatrix region. The main channel of radiative loss is carbon radiation, which cools the divertor plasma down to a few electronvolts, where hydrogen radiation losses become significant. The radiative losses preferentially reduce the power flux at the separatrix, leading to early detachment around the strike point position. With increasing density, the detached region extends upwards on the vertical target. The power fraction radiated in the LYRA divertor is around 45% and nearly independent of the heating power. This value is a factor of 2 higher than the typical radiation fraction in Div I. B2-EIRENE modelling of the performed experiments supports the experimental finding and refines the understanding of loss processes in the divertor region. (author)

  3. Doppler coherence imaging of ion dynamics in VINETA.II and ASDEX-upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Gradic, Dorothea; Ford, Oliver; Wolf, Robert [Max-Planck-Institut fuer Plasmaphysik, Greifswald (Germany); Lunt, Tilmann [Max-Planck-Institut fuer Plasmaphysik, Garching (Germany)

    2016-07-01

    In magnetically confining plasma experiments, diagnosis of ion flows is of great importance to measure the plasma response to the magnetic field or the exhaust particle flows in the divertor areas. Doppler coherence imaging spectroscopy (CIS) is a relatively new technique for the observation of plasma bulk ion dynamics. It is a passive optical diagnostic enabling line-integrated measurements to obtain 2D images of the ion flow and ion temperature. The general principle is similar to traditional Doppler spectroscopy, however CIS uses an imaging interferometer to perform narrow-bandwidth Fourier spectroscopy. A major advantage of the coherence imaging technique is the large amount of spatial information recovered. This allows tomographic inversion of the line-integrated measurements. With existing CIS setups, scrape-off-layer and high field side edge impurity flows could be observed in the MAST, core and edge poloidal He II flows in the WEGA stellarator and divertor impurity flows in DIII-D. The main objective of this study is the research of ion dynamics in the small linear plasma experiment VINETA.II and ASDEX-Upgrade. First Doppler CIS measurements from Ar-II plasma discharges in VINETA.II and He-II, C-III divertor flows in ASDEX-Upgrade and their preliminary interpretation will be presented.

  4. L-mode radiative plasma edge studies for model validation in ASDEX Upgrade and JET

    Energy Technology Data Exchange (ETDEWEB)

    Aho-Mantila, L., E-mail: leena.aho-mantila@vtt.fi [VTT Technical Research Centre of Finland, FI-02044 VTT (Finland); Bernert, M. [Max-Planck Institut für Plasmaphysik, D-85748 Garching (Germany); Coenen, J.W. [Energie- und Klimaforschung IEK-4, FZJ, EURATOM Association, TEC, 52425 Jülich (Germany); Fischer, R. [Max-Planck Institut für Plasmaphysik, D-85748 Garching (Germany); Lehnen, M. [Energie- und Klimaforschung IEK-4, FZJ, EURATOM Association, TEC, 52425 Jülich (Germany); Lowry, C. [EFDA JET CSU, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Marsen, S. [Max-Planck-Institut für Plasmaphysik, Teilinsitut Greifswald, D-17491 Greifswald (Germany); McCormick, K.; Müller, H.W.; Sieglin, B. [Max-Planck Institut für Plasmaphysik, D-85748 Garching (Germany); Stamp, M.F. [Culham Centre for Fusion Energy, EURATOM-CCFE Association, Abingdon (United Kingdom); Wischmeier, M. [Max-Planck Institut für Plasmaphysik, D-85748 Garching (Germany); Bonnin, X. [LSPM, CNRS, Université Paris 13, F-93430 Villetaneuse (France); Coster, D.P. [Max-Planck Institut für Plasmaphysik, D-85748 Garching (Germany); Reiter, D.; Brezinsek, S. [Energie- und Klimaforschung IEK-4, FZJ, EURATOM Association, TEC, 52425 Jülich (Germany)

    2013-07-15

    The presently favoured option for reactor power handling combines metallic plasma-facing components and impurity seeding to achieve highly radiative scrape-off layer and divertor plasmas. It is uncertain whether tolerable divertor power loads will be obtained in this scenario, necessitating the development of predictive modelling tools. L-mode experiments with N{sub 2} seeding have been conducted at both ASDEX Upgrade and JET for benchmarking the critically important impurity radiation models in edge fluid codes. In both machines, particle and power loads are observed to first reduce at the inner target, and only then at the outer target. The outer divertor cools down with increasing N seeding rate, evolving from low-recycling conditions to a regime with peak temperature of 8–10 eV in both devices. First SOLPS5.0 simulations of N{sub 2} seeding in ASDEX Upgrade geometry show a similar in–out asymmetry in the effect of impurity radiation when drifts are activated in the simulations.

  5. Extension of electron cyclotron heating at ASDEX Upgrade with respect to high density operation

    Directory of Open Access Journals (Sweden)

    Schubert Martin

    2017-01-01

    Full Text Available The ASDEX Upgrade electron cyclotron resonance heating operates at 105 GHz and 140 GHz with flexible launching geometry and polarization. In 2016 four Gyrotrons with 10 sec pulse length and output power close to 1 MW per unit were available. The system is presently being extended to eight similar units in total. High heating power and high plasma density operation will be a part of the future ASDEX Upgrade experiment program. For the electron cyclotron resonance heating, an O-2 mode scheme is proposed, which is compatible with the expected high plasma densities. It may, however, suffer from incomplete single-pass absorption. The situation can be improved significantly by installing holographic mirrors on the inner column, which allow for a second pass of the unabsorbed fraction of the millimetre wave beam. Since the beam path in the plasma is subject to refraction, the beam position on the holographic mirror has to be controlled. Thermocouples built into the mirror surface are used for this purpose. As a protective measure, the tiles of the heat shield on the inner column were modified in order to increase the shielding against unabsorbed millimetre wave power.

  6. Local effects of ECRH on argon transport at ASDEX upgrade

    International Nuclear Information System (INIS)

    Sertoli, Marco

    2010-01-01

    Future deuterium-tritium magnetically confined fusion power plants will most probably rely an high-Z Plasma Facing Components (PFCs) such as tungsten. This choice is determined by the necessity of low erosion of the first wall materials (to guarantee a long lifetime of the wall components) and by the need to avoid the too high tritium wall retention of typical carbon based PFCs. The experience gathered at the ASDEX Upgrade (AUG) tokamak has demonstrated the possibility of reliable and high performance plasma operation with a full tungsten-coated first wall. The observed accumulation of tungsten which can lead to excessive radiation losses is mitigated with the use of Electron Cyclotron Resonance Heating (ECRH). Although this impurity control method is routinely performed at AUG, the underlying physics principles are still not clear. This thesis aims an providing further knowledge an the effects of ECRH an the transport of impurities inside the core plasma. The transport of argon has been therefore investigated in-depth in purely ECR heated L-mode (low-confinement) discharges. Studies an impurity transport in centrally ECR heated nitrogen-seeded H-mode (high-confinement) discharges have also been performed. To this scope, a new crystal X-ray spectrometer of the Johann type has been installed an AUG for argon concentration and ion temperature measurements. New methods for the experimental determination of the total argon density through the integrated use of this diagnostic and of the Soft X-Ray (SXR) diode arrays have been developed. This gives the possibility of evaluating the full profiles of the argon transport coefficients from the linear flux-gradient dependency of local argon density. In comparison to classical χ 2 -minimization methods, the approach proposed here delivers transport coefficients intrinsically independent of the modelling of periodic relaxation mechanisms such as those Lied to sawtooth MHD (Magneto-Hydro-Dynamic) activity. Moreover, the good

  7. Heavy ion transport in the core of ASDEX upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Odstrcil, Tomas [Max-Planck-Institut fuer Plasmaphysik, Boltzmannstrasse 2, D-85748 Garching (Germany); Physik-Department E28, Technische Universitaet Muenchen, 85747 Garching (Germany); Puetterich, Thomas; Angioni, Clemente; Bilato, Roberto; Gude, Anja; Vezinet, Didier [Max-Planck-Institut fuer Plasmaphysik, Boltzmannstrasse 2, D-85748 Garching (Germany); Mazon, Didier [CEA, IRFM F-13108 Saint Paul-lez-Durance (France); Collaboration: ASDEX Upgrade Team

    2016-07-01

    High impurity concentration in the core of the future fusion reactors can lead to the serious degradation of the achievable fusion gain. Therefore, a better understanding of the underlying impurity transport processes is necessary for higher performance, more efficient power exhaust and avoidance of impurity accumulation. Radial impurity transport is mainly driven by neoclassical and turbulent particle fluxes. Both these components show substantial variation depending on the poloidal angle. Consequently, an asymmetry in the poloidal distribution of impurities leads to significant changes in the radial impurity flow and the total content of the plasma core. The aim of this contribution is to experimentally verify a model describing the poloidal asymmetry of heavy impurities using measurements from ASDEX Upgrade. The observed asymmetries are caused mainly by the centrifugal force and poloidal electric force created by the fast particles produced by intensive ion-cyclotron heating. Finally, a change in the radial transport of the tungsten ions will be presented in the case of large inboard and outboard impurity accumulation.

  8. Non-linear simulations of ELMs in ASDEX upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Lessig, Alexander; Hoelzl, Matthias; Orain, Francois; Guenter, Sibylle [Max-Planck-Institut fuer Plasmaphysik, Boltzmannstrasse 2, 85748 Garching (Germany); Becoulet, Marina; Huysmans, Guido [CEA-IRFM, Cadarache, 13108 Saint-Paul-Lez-Durance (France); Collaboration: the ASDEX Upgrade Team

    2016-07-01

    Large edge localized modes (ELMs) are a severe concern for the operation of future tokamak devices like ITER or DEMO due to the high transient heat loads induced on divertor targets and wall structures. It is therefore important to study ELMs both theoretically and experimentally in order to obtain a comprehensive understanding of the underlying mechanisms which is necessary for the prediction of ELM properties and the design of ELM mitigation systems. Using the non-linear MHD code JOREK, we have performed first simulations of full ELM crashes in ASDEX Upgrade, taking into account a large number of toroidal Fourier harmonics. The evolution of the toroidal mode spectrum has been investigated. In particular, we confirm the previously observed non-linear drive of linearly sub-dominant low-n components in the early non-linear phase of the ELM crash. Preliminary comparisons of the simulations with experimental observations regarding heat and particle losses, pedestal evolution and heat deposition patterns are shown. On the long run we aim at code validation as well as an improved understanding of the ELM dynamics and possibly a better characterization of different ELM types.

  9. A phased array antenna for Doppler reflectometry in ASDEX upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Wolf, Stefan; Lechte, Carsten; Kasparek, Walter [IGVP, Universitaet Stuttgart, D-70569 Stuttgart (Germany); Hennequin, Pascale [Laboratoire de Physique des Plasmas, CNRS, Ecole Polytech., F-91128 Palaiseau (France); Conway, Garrard; Happel, Tim [Max-Planck-Institut fuer Plasmaphysik, D-85748 Garching (Germany); Collaboration: ASDEX Upgrade Team

    2016-07-01

    In a toroidal plasma, Doppler reflectometry (DR) allows investigating electron density fluctuations with finite k {sub perpendicular} {sub to}. The injected microwave beam's frequency determines the radial position of the probed region, its tilt angle selects the wavenumber satisfying the Bragg condition for backscattering. The rotation velocity can be calculated from the Doppler shift of the backscattered signal's frequency. By varying the injected frequency, radial profiles can be reconstructed. Varying the tilt angle resolves the k {sub perpendicular} {sub to} -spectrum of the fluctuations. For DR, a pair of phased array antennas (PAAs) has been designed, built, and installed in the ASDEX Upgrade tokamak. Beam steering is done by slightly changing the injected frequency, thus, the PAAs do not need any movable parts or electronics inside the vacuum vessel. From 75 to 105 GHz, the PAAs feature 13 frequency bands, each with an angular scan range of -20 to +20 {sup circle}. So, for each angle, there are 13 radial positions to be probed. The results from PAA characterisation, commissioning, and first DR measurements are presented.

  10. Application of AXUV diode detectors at ASDEX Upgrade

    Science.gov (United States)

    Bernert, M.; Eich, T.; Burckhart, A.; Fuchs, J. C.; Giannone, L.; Kallenbach, A.; McDermott, R. M.; Sieglin, B.

    2014-03-01

    In the ASDEX Upgrade tokamak, a radiation measurement for a wide spectral range, based on semiconductor detectors, with 256 lines of sight and a time resolution of 5μs was recently installed. In combination with the foil based bolometry, it is now possible to estimate the absolutely calibrated radiated power of the plasma on fast timescales. This work introduces this diagnostic based on AXUV (Absolute eXtended UltraViolet) n-on-p diodes made by International Radiation Detectors, Inc. The measurement and the degradation of the diodes in a tokamak environment is shown. Even though the AXUV diodes are developed to have a constant sensitivity for all photon energies (1 eV-8 keV), degradation leads to a photon energy dependence of the sensitivity. The foil bolometry, which is restricted to a time resolution of less than 1 kHz, offers a basis for a time dependent calibration of the diodes. The measurements of the quasi-calibrated diodes are compared with the foil bolometry and found to be accurate on the kHz time scale. Therefore, it is assumed, that the corrected values are also valid for the highest time resolution (200 kHz). With this improved diagnostic setup, the radiation induced by edge localized modes is analyzed on fast timescales.

  11. Real-time diamagnetic flux measurements on ASDEX Upgrade.

    Science.gov (United States)

    Giannone, L; Geiger, B; Bilato, R; Maraschek, M; Odstrčil, T; Fischer, R; Fuchs, J C; McCarthy, P J; Mertens, V; Schuhbeck, K H

    2016-05-01

    Real-time diamagnetic flux measurements are now available on ASDEX Upgrade. In contrast to the majority of diamagnetic flux measurements on other tokamaks, no analog summation of signals is necessary for measuring the change in toroidal flux or for removing contributions arising from unwanted coupling to the plasma and poloidal field coil currents. To achieve the highest possible sensitivity, the diamagnetic measurement and compensation coil integrators are triggered shortly before plasma initiation when the toroidal field coil current is close to its maximum. In this way, the integration time can be chosen to measure only the small changes in flux due to the presence of plasma. Two identical plasma discharges with positive and negative magnetic field have shown that the alignment error with respect to the plasma current is negligible. The measured diamagnetic flux is compared to that predicted by TRANSP simulations. The poloidal beta inferred from the diamagnetic flux measurement is compared to the values calculated from magnetic equilibrium reconstruction codes. The diamagnetic flux measurement and TRANSP simulation can be used together to estimate the coupled power in discharges with dominant ion cyclotron resonance heating.

  12. Application of AXUV diode detectors at ASDEX Upgrade

    International Nuclear Information System (INIS)

    Bernert, M.; Eich, T.; Burckhart, A.; Fuchs, J. C.; Giannone, L.; Kallenbach, A.; McDermott, R. M.; Sieglin, B.

    2014-01-01

    In the ASDEX Upgrade tokamak, a radiation measurement for a wide spectral range, based on semiconductor detectors, with 256 lines of sight and a time resolution of 5μs was recently installed. In combination with the foil based bolometry, it is now possible to estimate the absolutely calibrated radiated power of the plasma on fast timescales. This work introduces this diagnostic based on AXUV (Absolute eXtended UltraViolet) n-on-p diodes made by International Radiation Detectors, Inc. The measurement and the degradation of the diodes in a tokamak environment is shown. Even though the AXUV diodes are developed to have a constant sensitivity for all photon energies (1 eV-8 keV), degradation leads to a photon energy dependence of the sensitivity. The foil bolometry, which is restricted to a time resolution of less than 1 kHz, offers a basis for a time dependent calibration of the diodes. The measurements of the quasi-calibrated diodes are compared with the foil bolometry and found to be accurate on the kHz time scale. Therefore, it is assumed, that the corrected values are also valid for the highest time resolution (200 kHz). With this improved diagnostic setup, the radiation induced by edge localized modes is analyzed on fast timescales

  13. Characterisation of the core poloidal flow at ASDEX upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Lebschy, Alexander [Max-Planck-Institut fuer Plasmaphysik, Boltzmannstr. 2, D-85748 Garching (Germany); Physik-Department E28, Technische Universitaet Muenchen, D-85748 Garching (Germany); McDermott, Rachael M.; Geiger, Benedikt; Cavedon, Marco; Dunne, Michael G.; Dux, Ralph; Fischer, Rainer; Kappatou, Athina; McCarthy, Patrick J.; Viezzer, Eleonora [Max-Planck-Institut fuer Plasmaphysik, Boltzmannstr. 2, D-85748 Garching (Germany); Collaboration: the ASDEX Upgrade Team

    2016-07-01

    Plasma rotation has a strong influence on the transport of heat, particles, and momentum in fusion plasmas via a variety of mechanisms, for example, by the stabilization of modes and the suppression of plasma turbulence. In tokamaks, the toroidal rotation (u{sub tor}) is essentially a free parameter that is usually dominated by the external momentum input from neutral beams used to heat the plasma. The poloidal rotation (u{sub pol}), on the other hand, is strongly damped and is predicted to remain at Neoclassical (NC) levels of a few km/s. Measuring the inboard-outboard asymmetry of u{sub tor} with charge exchange recombination spectroscopy enables an indirect measurement of u{sub pol} and, hence, the measurement of the complete plasma flow on a flux surface. In order to characterise the nature of u{sub pol} at ASDEX Upgrade a poloidal rotation database has been built that contains a large variation in the parameters that, according to NC theory, drive u{sub pol}; namely, the main ion temperature and density gradients and collisionality. Initial results from this database and a detailed comparison of u{sub pol} to NC theory in interesting plasma scenarios, are presented in this poster.

  14. Piezoelectric valve for massive gas injection in ASDEX upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Dibon, Mathias; Neu, Rudolf [Max-Planck-Institute for Plasmaphysics, Boltzmannstr. 2, 85748 Garching (Germany); Technical University Munich, Boltzmannstr. 15, 85748 Garching (Germany); Herrmann, Albrecht; Mank, Klaus; Mertens, Vitus; Pautasso, Gabriella; Ploeckl, Bernhard [Max-Planck-Institute for Plasmaphysics, Boltzmannstr. 2, 85748 Garching (Germany)

    2016-07-01

    A sudden loss of plasma temperature can cause a disruption, which poses a significant problem for current Tokamaks and future fusion devices. Hence, mitigating forces and thermal loads during disruptions is important for the integrity of the vessel and first wall components. Therefore, high speed gas valves are used to deliver a pulse of noble gas onto the plasma, which irradiates the thermal energy quickly, avoiding localized heat loads and mechanical stress due to induced currents. A new design for such a valve is currently under development. The valve plate is driven by two piezoelectric stack actuators. The stroke of the actuators (0.07 mm) is amplified by a monolithic titanium frame and reaches 2 mm. The frame also serves as spring to pre-load the actuators. In the idle state, it also presses the conical valve plate into the seal, closing the gas chamber (42 cm{sup 3}). The actuators accelerate the stem and the valve plate until it is fully opened after 2 ms. The orifice of the valve has a diameter of 14 mm. This allows a peak mass flow rate of the gas up to 8 . 10{sup 4} (Pa.m)/(s) after 1.8 ms and an average mass flow rate of 2 . 10{sup 4} (Pa.m)/(s) over the evacuation time of 10 ms. Therefore, one valve would be sufficient to deliver the required amount of gas to mitigate disruptions at ASDEX Upgrade.

  15. Major upgrades of the high frequency B-dot probe diagnostic suite on ASDEX Upgrade

    Directory of Open Access Journals (Sweden)

    Ochoukov Roman

    2017-01-01

    Full Text Available The high frequency B-dot (HFB probe diagnostic on the ASDEX Upgrade tokamak has undergone a considerable upgrade during the 2016 opening of the torus. The probe coverage is now greatly expanded toroidally, as well as radially with the addition of probes on the high field side and the removable manipulator head. A new 2-channel fast digitizer now allows to examine and record radio frequency (RF wave emissions emanating from the plasma in the ion cyclotron range of frequencies (ICRF. Possible studies that can be achieved now include: a study of core ICRF power absorption efficiency; a study of ion cyclotron emissions from the plasma generated by energetic ions; and study of ICRF wave/plasma turbulence interactions in the scrape-off layer region.

  16. Controlled tungsten melting and droplet ejection studies in ASDEX Upgrade

    International Nuclear Information System (INIS)

    Krieger, K; Lunt, T; Dux, R; Janzer, A; Müller, H W; Potzel, S; Pütterich, T; Yang, Z

    2011-01-01

    Tungsten rods of 1×1×3 mm 3 were exposed in single H-mode discharges at the outer divertor target plate of ASDEX Upgrade using the divertor manipulator system. Melting of the W rod at a pre-defined time was induced by moving the initially far away outer strike point close to the W-rod position. Visible light emissions of both the W pin and consecutively ejected W droplets were recorded by two fast cameras with crossed viewing cones. The time evolution of the local W source at the pin location was measured by spectroscopic observation of the WI line emission at 400.9 nm and compared to the subsequent increase of tungsten concentration in the confined plasma derived from tungsten vacuum UV line emission. Combining these measurements with the total amount of released tungsten due to the pin melt events and ejected droplets allowed us to derive an estimate of the screening factor for this type of tungsten source. The resulting values of the tungsten divertor retention in the range 10-20 agree with those found in previous studies using a W source of sublimated W(CO) 6 vapour at the same exposure location. Ejected droplets were found to be always accelerated in the general direction of the plasma flow, attributed to friction forces and to rocket forces. Furthermore, the vertically inclined target plates cause the droplets, which are repelled by the target plate surface potential due to their electric charge, to move upwards against gravity due to the centrifugal force component parallel to the target plate.

  17. Improvements for real-time magnetic equilibrium reconstruction on ASDEX Upgrade

    International Nuclear Information System (INIS)

    Giannone, L.; Fischer, R.; McCarthy, P.J.; Odstrcil, T.; Zammuto, I.; Bock, A.; Conway, G.; Fuchs, J.C.; Gude, A.; Igochine, V.; Kallenbach, A.; Lackner, K.; Maraschek, M.; Rapson, C.; Ruan, Q.; Schuhbeck, K.H.; Suttrop, W.; Wenzel, L.

    2015-01-01

    Highlights: • Spline basis current functions with second-order linear regularisation. • Perturbations of magnetic probe measurements due to ferromagnetic tiles on the inner wall and from oscillations in the fast position coil current are corrected. • A constraint of the safety factor on the magnetic axis is introduced. Soft X-ray tomography is used to assess the quality of the real-time magnetic equilibrium reconstruction. • External loop voltage measurements and magnetic probe pairs inside and outside the vessel wall were used to measure the vacuum vessel wall resistivity. - Abstract: Real-time magnetic equilibria are needed for NTM stabilization and disruption avoidance experiments on ASDEX Upgrade. Five improvements to real-time magnetic equilibrium reconstruction on ASDEX Upgrade have been investigated. The aim is to include as many features of the offline magnetic equilibrium reconstruction code in the real-time equilibrium reconstruction code. Firstly, spline current density basis functions with regularization are used in the offline equilibrium reconstruction code, CLISTE [1]. It is now possible to have the same number of spline basis functions in the real-time code. Secondly, in the presence of edge localized modes, (ELM's), it is found to be necessary to include the low pass filter effect of the vacuum vessel on the fast position control coil currents to correctly compensate the magnetic probes for current oscillations in these coils. Thirdly, the introduction of ferromagnetic tiles in ASDEX Upgrade means that a real-time algorithm for including the perturbations of the magnetic equilibrium generated by these tiles is required. A methodology based on tile surface currents is described. Fourthly, during current ramps it was seen that the difference between fitted and measured magnetic measurements in the equilibrium reconstruction were larger than in the constant current phase. External loop voltage measurements and magnetic probe pairs inside and

  18. Improvements for real-time magnetic equilibrium reconstruction on ASDEX Upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Giannone, L.; Fischer, R. [Max Planck Institute for Plasma Physics, 85748 Garching (Germany); McCarthy, P.J. [Department of Physics, University College Cork, Cork (Ireland); Odstrcil, T.; Zammuto, I.; Bock, A.; Conway, G.; Fuchs, J.C.; Gude, A.; Igochine, V.; Kallenbach, A.; Lackner, K.; Maraschek, M.; Rapson, C. [Max Planck Institute for Plasma Physics, 85748 Garching (Germany); Ruan, Q. [National Instruments, Austin, TX 78759-3504 (United States); Schuhbeck, K.H.; Suttrop, W. [Max Planck Institute for Plasma Physics, 85748 Garching (Germany); Wenzel, L. [National Instruments, Austin, TX 78759-3504 (United States)

    2015-11-15

    Highlights: • Spline basis current functions with second-order linear regularisation. • Perturbations of magnetic probe measurements due to ferromagnetic tiles on the inner wall and from oscillations in the fast position coil current are corrected. • A constraint of the safety factor on the magnetic axis is introduced. Soft X-ray tomography is used to assess the quality of the real-time magnetic equilibrium reconstruction. • External loop voltage measurements and magnetic probe pairs inside and outside the vessel wall were used to measure the vacuum vessel wall resistivity. - Abstract: Real-time magnetic equilibria are needed for NTM stabilization and disruption avoidance experiments on ASDEX Upgrade. Five improvements to real-time magnetic equilibrium reconstruction on ASDEX Upgrade have been investigated. The aim is to include as many features of the offline magnetic equilibrium reconstruction code in the real-time equilibrium reconstruction code. Firstly, spline current density basis functions with regularization are used in the offline equilibrium reconstruction code, CLISTE [1]. It is now possible to have the same number of spline basis functions in the real-time code. Secondly, in the presence of edge localized modes, (ELM's), it is found to be necessary to include the low pass filter effect of the vacuum vessel on the fast position control coil currents to correctly compensate the magnetic probes for current oscillations in these coils. Thirdly, the introduction of ferromagnetic tiles in ASDEX Upgrade means that a real-time algorithm for including the perturbations of the magnetic equilibrium generated by these tiles is required. A methodology based on tile surface currents is described. Fourthly, during current ramps it was seen that the difference between fitted and measured magnetic measurements in the equilibrium reconstruction were larger than in the constant current phase. External loop voltage measurements and magnetic probe pairs inside

  19. ASDEX Upgrade Discharge Control System—A real-time plasma control framework

    International Nuclear Information System (INIS)

    Treutterer, W.; Cole, R.; Lüddecke, K.; Neu, G.; Rapson, C.; Raupp, G.; Zasche, D.; Zehetbauer, T.

    2014-01-01

    Highlights: • The ASDEX Upgrade Discharge Control System (DCS) is a comprehensive control system to conduct fusion experiments. • DCS supports real-time diagnostic integration, adaptable feedback schemes, actuator management and exception handling. • DCS offers workflow management, logging and archiving, self-monitoring and inter-process communication. • DCS is based on a distributed, modular software framework architecture designed for real-time operation. • DCS is composed of re-usable generic but highly customisable components. - Abstract: ASDEX Upgrade is a fusion experiment with a size and complexity to allow extrapolation of technical and physical conditions and requirements to devices like ITER and even beyond. In addressing advanced physics topics it makes extensive use of sophisticated real-time control methods. It comprises real-time diagnostic integration, dynamically adaptable multivariable feedback schemes, actuator management including load distribution schemes and a powerful monitoring and pulse supervision concept based on segment scheduling and exception handling. The Discharge Control System (DCS) supplies all this functionality on base of a modular software framework architecture designed for real-time operation. It provides system-wide services like workflow management, logging and archiving, self-monitoring and inter-process communication on Linux, VxWorks and Solaris operating systems. By default DCS supports distributed computing, and a communication layer allows multi-directional signal transfer and data-driven process synchronisation over shared memory as well as over a number of real-time networks. The entire system is built following the same common design concept combining a rich set of re-usable generic but highly customisable components with a configuration-driven component deployment method. We will give an overview on the architectural concepts as well as on the outstanding capabilities of DCS in the domains of inter

  20. ASDEX Upgrade Discharge Control System—A real-time plasma control framework

    Energy Technology Data Exchange (ETDEWEB)

    Treutterer, W., E-mail: Wolfgang.Treutterer@ipp.mpg.de [Max-Planck-Institut für Plasmaphysik, EURATOM Association, Boltzmannstraße 2, 85748 Garching (Germany); Cole, R.; Lüddecke, K. [Unlimited Computer Systems GmbH, Iffeldorf (Germany); Neu, G.; Rapson, C.; Raupp, G.; Zasche, D.; Zehetbauer, T. [Max-Planck-Institut für Plasmaphysik, EURATOM Association, Boltzmannstraße 2, 85748 Garching (Germany)

    2014-03-15

    Highlights: • The ASDEX Upgrade Discharge Control System (DCS) is a comprehensive control system to conduct fusion experiments. • DCS supports real-time diagnostic integration, adaptable feedback schemes, actuator management and exception handling. • DCS offers workflow management, logging and archiving, self-monitoring and inter-process communication. • DCS is based on a distributed, modular software framework architecture designed for real-time operation. • DCS is composed of re-usable generic but highly customisable components. - Abstract: ASDEX Upgrade is a fusion experiment with a size and complexity to allow extrapolation of technical and physical conditions and requirements to devices like ITER and even beyond. In addressing advanced physics topics it makes extensive use of sophisticated real-time control methods. It comprises real-time diagnostic integration, dynamically adaptable multivariable feedback schemes, actuator management including load distribution schemes and a powerful monitoring and pulse supervision concept based on segment scheduling and exception handling. The Discharge Control System (DCS) supplies all this functionality on base of a modular software framework architecture designed for real-time operation. It provides system-wide services like workflow management, logging and archiving, self-monitoring and inter-process communication on Linux, VxWorks and Solaris operating systems. By default DCS supports distributed computing, and a communication layer allows multi-directional signal transfer and data-driven process synchronisation over shared memory as well as over a number of real-time networks. The entire system is built following the same common design concept combining a rich set of re-usable generic but highly customisable components with a configuration-driven component deployment method. We will give an overview on the architectural concepts as well as on the outstanding capabilities of DCS in the domains of inter

  1. Inter-ELM pedestal structure development in ASDEX upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Laggner, Florian Martin

    2017-06-15

    The performance of a magnetically confined, fusion plasma is strongly impacted by the plasma edge, which is the boundary between the hot, confined plasma and the reactor walls. In a tokamak, which uses a toroidally axis-symmetric magnetic field configuration, a regime of improved plasma confinement, the high confinement mode (H-mode), has been observed. The confinement improvement originates from an edge transport barrier (ETB), which is accompanied by steep gradients of the plasma pressure, named pedestal. The maximum sustainable pedestal, i.e. the maximum pressure gradient, is usually set by an ideal magnetohydrodynamic limit, which if exceeded is leading to edge localised modes (ELMs). ELMs are instabilities that relax the pedestal and lead to a loss of the order of 10% from the plasma stored energy. The mechanisms, which set the pedestal structure before an ELM crash, keeping the pedestal stable up to this point, are not fully understood. Here, microturbulent instabilities, e.g. kinetic ballooning modes (KBMs), are expected to play an important role. The presented PhD thesis investigates the temporal development of the pedestal density and temperature profiles in between ELM crashes at the ASDEX Upgrade tokamak. The aims were comparisons of different plasma conditions, i.e. plasma collisionality (ν{sup *}), main isotope species and plasma shapes. Further, the impact of the conditions outside the confined plasma on the pedestal development was investigated. The extensive study of these parameters resulted in one key observation: The pedestal recovers in distinct phases in between ELM crashes with always the same sequence. Immediately after the ELM crash, the electron density (n{sub e}) pedestal is established, followed by the electron temperature (T{sub e}) pedestal. Finally, a period with constant pressure gradient appears, which can vary in duration. For a large range of ν{sup *} it has been found that the onset of radial magnetic fluctuations with

  2. Thyristor crowbar system for the high current power supplies of ASDEX upgrade

    International Nuclear Information System (INIS)

    Kaesemann, C.-P.; Lieshout, L. van; Huart, M.; Sihler, C.

    2005-01-01

    The ohmic heating system and the poloidal field coils of ASDEX upgrade are supplied by 15 thyristor converter units with an installed apparent power of 600 MVA. To protect the thyristor converters against dc overvoltage arising from abnormal operations and resulting damages caused by the large energy stored in the AUG magnet coils an overvoltage protection system was required. The paper describes the motivation for-and the design and testing of the thyristor crowbar system representing the thyristor converter overvoltage protection system. It will present the layout, analyse the results of measurements obtained during commissioning, compare them to the calculated (design) values and report on the first experience of operation on the AUG coils improving the safety of the equipment

  3. The physics of W transport illuminated by recent progress in W density diagnostics at ASDEX Upgrade

    Science.gov (United States)

    Odstrcil, T.; Pütterich, T.; Angioni, C.; Bilato, R.; Gude, A.; Odstrcil, M.; ASDEX Upgrade Team; the EUROfusion MST1 Team

    2018-01-01

    Due to the high mass and charge of the heavy ions, centrifugal and electrostatic forces cause a significant variation in their poloidal density. The impact of these forces on the poloidal density profile of tungsten was investigated utilizing the detailed two-dimensional SXR emissivity profiles from the ASDEX Upgrade tokamak. The perturbation in the electrostatic potential generated by magnetic trapping of the non-thermal ions from neutral beam injection was found to be responsible for significant changes in the poloidal distribution of tungsten ions. An excellent match with the results from fast particle modeling was obtained, validating the model for the poloidal fast particle distribution. Additionally, an enhancement of the neoclassical transport due to an outboard side impurity localization was measured in the experiment when analyzing the tungsten flux between sawtooth crashes. A qualitative match with neoclassical modeling was found, demonstrating the possibility of minimizing neoclassical transport by an optimization of the poloidal asymmetry profile of the impurity.

  4. Axisymmetric disruption dynamics including current profile changes in the ASDEX-Upgrade tokamak

    International Nuclear Information System (INIS)

    Nakamura, Y.; Pautasso, G.; Gruber, O.; Jardin, S.C.

    2002-01-01

    Axisymmetric MHD simulations have revealed a new driving mechanism that governs the vertical displacement event (VDE) dynamics in tokamak disruptions. A rapid flattening of the plasma current profile during the disruption plays a substantial role in dragging a single null-diverted plasma vertically towards the divertor. As a consequence, the occurrence of downward-going VDEs predominates over the upward-going ones in bottom-diverted discharges. This dragging effect, due to an abrupt change in the current profile, is absent in up-down symmetric limiter discharges. These simulation results are consistent with experiments in ASDEX-Upgrade. Together with the attractive force that arises from passive shell currents induced by the plasma current quench, the dragging effect explains many details of the VDE dynamics over the whole period of the disruptive termination. (author)

  5. Criteria and algorithms for constructing reliable databases for statistical analysis of disruptions at ASDEX Upgrade

    International Nuclear Information System (INIS)

    Cannas, B.; Fanni, A.; Pautasso, G.; Sias, G.; Sonato, P.

    2009-01-01

    The present understanding of disruption physics has not gone so far as to provide a mathematical model describing the onset of this instability. A disruption prediction system, based on a statistical analysis of the diagnostic signals recorded during the experiments, would allow estimating the probability of a disruption to take place. A crucial point for a good design of such a prediction system is the appropriateness of the data set. This paper reports the details of the database built to train a disruption predictor based on neural networks for ASDEX Upgrade. The criteria of pulses selection, the analyses performed on plasma parameters and the implemented pre-processing algorithms, are described. As an example of application, a short description of the disruption predictor is reported.

  6. Model-based radiation scalings for the ITER-like divertors of JET and ASDEX Upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Aho-Mantila, L., E-mail: leena.aho-mantila@vtt.fi [VTT Technical Research Centre of Finland, FI-02044 VTT (Finland); Bonnin, X. [LSPM – CNRS, Université Paris 13, Sorbonne Paris Cité, F-93430 Villetaneuse (France); Coster, D.P. [Max-Planck Institut für Plasmaphysik, D-85748 Garching (Germany); Lowry, C. [EFDA JET CSU, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Wischmeier, M. [Max-Planck Institut für Plasmaphysik, D-85748 Garching (Germany); Brezinsek, S. [Forschungszentrum Jülich, Institut für Energie- und Klimaforschung Plasmaphysik, 52425 Jülich (Germany); Federici, G. [EFDA PPP& T Department, D-85748 Garching (Germany)

    2015-08-15

    Effects of N-seeding in L-mode experiments in ASDEX Upgrade and JET are analysed numerically with the SOLPS5.0 code package. The modelling yields 3 qualitatively different radiative regimes with increasing N concentration, when initially attached outer divertor conditions are studied. The radiation pattern is observed to evolve asymmetrically, with radiation increasing first in the inner divertor, then in the outer divertor, and finally on closed field lines above the X-point. The properties of these radiative regimes are observed to be sensitive to cross-field drifts and they differ between the two devices. The modelled scaling of the divertor radiated power with the divertor neutral pressure is similar to an experimental scaling law for H-mode radiation. The same parametric dependencies are not observed in simulations without drifts.

  7. Simulation of feedback control system for NTM stabilisation in ASDEX Upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Rapson, Christopher, E-mail: chris.rapson@ipp.mpg.de [Max Planck Institute for Plasma Physics, EURATOM Association, Boltzmannstrasse 2, 85748 Garching (Germany); Monaco, Francesco; Reich, Matthias; Stober, Joerg; Treutterer, Wolfgang [Max Planck Institute for Plasma Physics, EURATOM Association, Boltzmannstrasse 2, 85748 Garching (Germany)

    2013-10-15

    Highlights: ► Feedback loop to control the ECRH deposition location is modelled in Simulink. Controller optimised using simulation results. ► Apart from optimising the PID gain values, alternative architectures were trialed without risk to hardware. ► Off-normal events could be simulated, and the controller response improved. ► Optimised controller applied in experiment. Even for the low power used, partial stabilisation of NTM was observed. ► The simulation is useful outside its intended application, and for future developments of the NTM feedback control system. -- Abstract: Neoclassical Tearing Modes (NTMs) are a class of MHD instability in high beta tokamak plasmas which significantly increase radial transport, thus capping the performance of fusion plasmas. More importantly, NTMs can lead to disruptions which compromise the lifetime of structural components. Several tokamaks have demonstrated that Electron Cyclotron Resonant Heating (ECRH) can stabilise NTMs if the power deposition is aligned with the mode location. The deposition location depends on the toroidal magnetic field, flux and density profiles, and can be controlled by tilting the mirror in the ECRH launcher. Until recently, the mirror angle was set by feedforward control at ASDEX Upgrade. In order to adapt automatically to different discharge scenarios, the system at ASDEX Upgrade has been extended to steer the mirror using feedback control. The mirror must react on the current diffusion time scale, on the order of 100 ms. This is within the capabilities of the mechanical subsystem and real-time plasma diagnostics, but requires careful interfacing between these components. For example, asynchronous data transfer and non-linearities make it difficult to design an analytically optimal controller. Therefore a simulation has been used to test and tune different controller architectures. This simulation is the subject of the current contribution. Performing the optimisation process offline

  8. Fast-ion losses induced by ACs and TAEs in the ASDEX Upgrade tokamak

    NARCIS (Netherlands)

    M. García-Muñoz,; Hicks, N.; van Voornveld, R.; Classen, I.G.J.; Bilato, R.; Bobkov, V.; Brambilla, M.; Bruedgam, M.; Fahrbach, H. U.; Igochine, V.; Jaemsae, S.; Maraschek, M.; Sassenberg, K.

    2010-01-01

    The phase-space of convective and diffusive fast-ion losses induced by shear Alfven eigenmodes has been characterized in the ASDEX Upgrade tokamak. Time-resolved energy and pitch-angle measurements of fast-ion losses correlated in frequency and phase with toroidal Alfven eigenmodes (TAEs) and Alfven

  9. Fast-ion losses induced by ACs and TAEs in the ASDEX Upgrade tokamak

    NARCIS (Netherlands)

    García-Munoz, M.; Hicks, N.; Voornveld, van R.; Classen, I.G.J.; Bilato, R.; Bobkov, V.; Brambilla, M.; Bruedgam, M.; Fahrbach, H. -U.; Igochine, V.; Jaemsae, S.; Maraschek, M.; Sassenberg, K.

    2010-01-01

    The phase-space of convective and diffusive fast-ion losses induced by shear Alfv´en eigenmodes has been characterized in the ASDEX Upgrade tokamak. Time-resolved energy and pitch-angle measurements of fast-ion losses correlated in frequency and phase with toroidal Alfv´en eigenmodes (TAEs) and

  10. Plasma shut-down with fast impurity puff on ASDEX Upgrade

    International Nuclear Information System (INIS)

    Pautasso, G.; Fuchs, C.J.; Gruber, O.; Maggi, C.F.; Maraschek, M.; Puetterich, T.; Rohde, V.; Wittmann, C.; Wolfrum, E.; Cierpka, P.; Beck, M.

    2007-01-01

    The massive injection of impurity gas into a plasma has been proved to reduce forces and localized thermal loads caused by disruptions in tokamaks. This mitigation system is routinely used on ASDEX Upgrade to shut down plasmas with a locked mode. The plasma response to impurity injection and the mechanism of reduction of the mechanical forces is discussed in the paper

  11. Expected performance properties of the ASDEX upgrade toroidal field magnet derived from calculations and materials investigations

    International Nuclear Information System (INIS)

    Streibl, B.; Mukherjee, S.

    1989-11-01

    This is a summary of the TF-magnet calculation results for the 1984 phase-II proposal including supplements (also considering disturbances) of the performance of ASDEX Upgrade. Calculation results are as reliable as the assumptions incorporated, so that investigations of materials and design components were always used to complete the calculations. (orig.) [de

  12. Commissioning of inline ECE system within waveguide based ECRH transmission systems on ASDEX upgrade

    DEFF Research Database (Denmark)

    Bongers, W. A.; Kasparek, W.; Doelman, N.

    2012-01-01

    A CW capable inline electron cyclotron emission (ECE) separation system for feedback control, featuring oversized corrugated waveguides, is commissioned on ASDEX upgrade (AUG). The system is based on a combination of a polarization independent, non-resonant, Mach-Zehnder diplexer equipped with di...

  13. Commissioning of inline ECE system within waveguide based ECRH transmission systems on ASDEX upgrade

    NARCIS (Netherlands)

    Bongers, W.A.; Kasparek, W.; Doelman, N. J.; Braber, R. van den; Brand, H. van den; Meo, F.; Baar, M.R. de; Amerongen, F.J.; Donné, A.J.H.; Elzendoorn, B.S.Q.; Erckmann, V.; Goede, A.P.H.; Giannone, L.; Grünwald, G.; Hollman, F.; Kaas, G.; Krijger, B.; Michel, G.; Lubyako, L.; Monaco, F.; Noke, F.; Petelin, M.; Plaum, B.; Purps, F.; Pierik, J.G.W. ten; Schüller, C.; Slob, J.W.; Stober, J.K.; Schütz, H.; Wagner, D.; Westerhof, E.; Ronden, D.M.S.

    2012-01-01

    A CW capable inline electron cyclotron emission (ECE) separation system for feedback control, featuring oversized corrugated waveguides, is commissioned on ASDEX upgrade (AUG). The system is based on a combination of a polarization independent, non-resonant, Mach-Zehnder diplexer equipped with

  14. Simultaneous Measurements of Electrostatic and Magnetic Fluctuations in ASDEX Upgrade Edge Plasma

    DEFF Research Database (Denmark)

    Ionita, Codrina; Vianello, Nicola; Müller, H.W.

    2009-01-01

    In ASDEX Upgrade (AUG) electrostatic and magnetic fluctuations in the edge plasma region were measured simultaneously during ELMy H-mode (high confinement) plasmas and L-mode (low confinement) plasmas and during a transition between the two modes. A special probe was used containing six Langmuir...

  15. Commissioning activities and first results from the collective Thomson scattering diagnostic on ASDEX Upgrade (invited)

    DEFF Research Database (Denmark)

    Meo, Fernando; Bindslev, Henrik; Korsholm, Søren Bang

    2008-01-01

    of the system. First results in near perpendicular of scattered spectra in a neutral beam injection (NBI) and ion cyclotron resonance heating (ICRH) plasma (minority hydrogen) on ASDEX Upgrade have shown evidence of ICRH heating phase of hydrogen. ©2008 American Institute of Physics...

  16. Fast-ion transport induced by Alfvén eigenmodes in the ASDEX Upgrade tokamak

    DEFF Research Database (Denmark)

    Garcia-Munoz, M.; Classen, I.G.J.; Geiger, B.

    2011-01-01

    A comprehensive suite of diagnostics has allowed detailed measurements of the Alfvén eigenmode (AE) spatial structure and subsequent fast-ion transport in the ASDEX Upgrade (AUG) tokamak [1]. Reversed shear Alfvén eigenmodes (RSAEs) and toroidal induced Alfvén eigenmodes (TAEs) have been driven u...

  17. Configuration-defined control algorithms with the ASDEX Upgrade DCS

    Energy Technology Data Exchange (ETDEWEB)

    Treutterer, Wolfgang, E-mail: Wolfgang.Treutterer@ipp.mpg.de [Max-Planck-Institut für Plasmaphysik, Boltzmannstr. 2, 85748 Garching (Germany); Cole, Richard [Unlimited Computer Systems, Seeshaupter Str. 15, 82393 Iffeldorf Germany (Germany); Gräter, Alexander [Max-Planck-Institut für Plasmaphysik, Boltzmannstr. 2, 85748 Garching (Germany); Lüddecke, Klaus [Unlimited Computer Systems, Seeshaupter Str. 15, 82393 Iffeldorf Germany (Germany); Neu, Gregor; Rapson, Christopher; Raupp, Gerhard; Zehetbauer, Thomas [Max-Planck-Institut für Plasmaphysik, Boltzmannstr. 2, 85748 Garching (Germany)

    2016-11-15

    Highlights: • Control algorithm built from combination of pre-fabricated standard function blocks. • Seamless integration in multi-threaded computation context. • Block composition defined by configuration data, only. - Abstract: The ASDEX Upgrade Discharge Control System (DCS) is a distributed real-time control system executing complex control and monitoring tasks. Up to now, DCS control algorithms have been implemented by coding dedicated application processes with the C++ programming language. Algorithm changes required code modification, compilation and commissioning which only experienced programmers could perform. This was a significant constraint of flexibility for both control system operation and design. The new approach extends DCS with the capability of configuration-defined control algorithms. These are composed of chains of small, configurable standard function blocks providing general purpose functions like algebraic operations, filters, feedback controllers, output limiters and decision logic. In a later phase a graphical editor could help to compose and modify such configuration in a Simulink-like fashion. Building algorithms from standard functions can result in a high number of elements. In order to achieve a similar performance as with C++ coding, it is essential to avoid administrative bottlenecks by design. As a consequence, DCS executes a function block chain in the context of a single real-time thread of an application process. No concurrency issues as in a multi-threaded context need to be considered resulting in strongly simplified signal handling and zero performance overhead for inter-block communication. Instead of signal-driven synchronization, a block scheduler derives the execution sequence automatically from the block dependencies as defined in the configuration. All blocks and connecting signals are instantiated dynamically, based on definitions in a configuration file. Algorithms thus are not defined in the code but only in

  18. Event detection and exception handling strategies in the ASDEX Upgrade discharge control system

    International Nuclear Information System (INIS)

    Treutterer, W.; Neu, G.; Rapson, C.; Raupp, G.; Zasche, D.; Zehetbauer, T.

    2013-01-01

    Highlights: •Event detection and exception handling is integrated in control system architecture. •Pulse control with local exception handling and pulse supervision with central exception handling are strictly separated. •Local exception handling limits the effect of an exception to a minimal part of the controlled system. •Central Exception Handling solves problems requiring coordinated action of multiple control components. -- Abstract: Thermonuclear plasmas are governed by nonlinear characteristics: plasma operation can be classified into scenarios with pronounced features like L and H-mode, ELMs or MHD activity. Transitions between them may be treated as events. Similarly, technical systems are also subject to events such as failure of measurement sensors, actuator saturation or violation of machine and plant operation limits. Such situations often are handled with a mixture of pulse abortion and iteratively improved pulse schedule reference programming. In case of protection-relevant events, however, the complexity of even a medium-sized device as ASDEX Upgrade requires a sophisticated and coordinated shutdown procedure rather than a simple stop of the pulse. The detection of events and their intelligent handling by the control system has been shown to be valuable also in terms of saving experiment time and cost. This paper outlines how ASDEX Upgrade's discharge control system (DCS) detects events and handles exceptions in two stages: locally and centrally. The goal of local exception handling is to limit the effect of an unexpected or asynchronous event to a minimal part of the controlled system. Thus, local exception handling facilitates robustness to failures but keeps the decision structures lean. A central state machine deals with exceptions requiring coordinated action of multiple control components. DCS implements the state machine by means of pulse schedule segments containing pre-programmed waveforms to define discharge goal and control

  19. Event detection and exception handling strategies in the ASDEX Upgrade discharge control system

    Energy Technology Data Exchange (ETDEWEB)

    Treutterer, W., E-mail: Wolfgang.Treutterer@ipp.mpg.de; Neu, G.; Rapson, C.; Raupp, G.; Zasche, D.; Zehetbauer, T.

    2013-10-15

    Highlights: •Event detection and exception handling is integrated in control system architecture. •Pulse control with local exception handling and pulse supervision with central exception handling are strictly separated. •Local exception handling limits the effect of an exception to a minimal part of the controlled system. •Central Exception Handling solves problems requiring coordinated action of multiple control components. -- Abstract: Thermonuclear plasmas are governed by nonlinear characteristics: plasma operation can be classified into scenarios with pronounced features like L and H-mode, ELMs or MHD activity. Transitions between them may be treated as events. Similarly, technical systems are also subject to events such as failure of measurement sensors, actuator saturation or violation of machine and plant operation limits. Such situations often are handled with a mixture of pulse abortion and iteratively improved pulse schedule reference programming. In case of protection-relevant events, however, the complexity of even a medium-sized device as ASDEX Upgrade requires a sophisticated and coordinated shutdown procedure rather than a simple stop of the pulse. The detection of events and their intelligent handling by the control system has been shown to be valuable also in terms of saving experiment time and cost. This paper outlines how ASDEX Upgrade's discharge control system (DCS) detects events and handles exceptions in two stages: locally and centrally. The goal of local exception handling is to limit the effect of an unexpected or asynchronous event to a minimal part of the controlled system. Thus, local exception handling facilitates robustness to failures but keeps the decision structures lean. A central state machine deals with exceptions requiring coordinated action of multiple control components. DCS implements the state machine by means of pulse schedule segments containing pre-programmed waveforms to define discharge goal and control

  20. Upgrades and Real Time Ntm Control Application of the Ece Radiometer on Asdex Upgrade

    Science.gov (United States)

    Hicks, N. K.; Suttrop, W.; Behler, K.; Giannone, L.; Manini, A.; Maraschek, M.; Raupp, G.; Reich, M.; Sips, A. C. C.; Stober, J.; Treutterer, W.; ASDEX Upgrade Team; Cirant, S.

    2009-04-01

    The 60-channel electron cyclotron emission (ECE) radiometer diagnostic on the ASDEX Upgrade tokamak is presently being upgraded to include a 1 MHz sampling rate data acquisition system. This expanded capability allows electron temperature measurements up to 500 kHz (anti-aliasing filter cut-off) with spatial resolution ~1 cm, and will thus provide measurement of plasma phenomena on the MHD timescale, such as neoclassical tearing modes (NTMs). The upgraded and existing systems may be run in parallel for comparison, and some of the first plasma measurements using the two systems together are presented. A particular planned application of the upgraded radiometer is integration into a real-time NTM stabilization loop using targeted deposition of electron cyclotron resonance heating (ECRH). For this loop, it is necessary to determine the locations of the NTM and ECRH deposition using ECE measurements. As the magnetic island of the NTM repeatedly rotates through the ECE line of sight, electron temperature fluctuations at the NTM frequency are observed. The magnetic perturbation caused by the NTM is independently measured using Mirnov coils, and a correlation profile between these magnetic measurements and the ECE data is constructed. The phase difference between ECE oscillations on opposite sides of the island manifests as a zero-crossing of the correlation profile, which determines the NTM location in ECE channel space. To determine the location of ECRH power deposition, the power from a given gyrotron may be modulated at a particular frequency. Correlation analysis of this modulated signal and the ECE data identifies a particular ECE channel associated with the deposition of that gyrotron. Real time equilibrium reconstruction allows the ECE channels to be translated into flux surface and spatial coordinates for use in the feedback loop.

  1. Upgrade to the control system of the reflectometry diagnostic of ASDEX upgrade

    International Nuclear Information System (INIS)

    Graca, S.; Santos, J.; Manso, M.E.

    2004-01-01

    The broadband frequency modulation-continuous wave microwave/millimeter wave reflectometer of ASDEX upgrade tokamak (Institut fuer Plasma Physik (IPP), Garching, Germany) developed by Centro de Fusao Nuclear (Lisboa, Portugal) with the collaboration of IPP, is a complex system with 13 channels (O and X modes) and two types of operation modes (swept and fixed frequency). The control system that ensures remote operation of the diagnostic incorporates VME and CAMAC bus based acquisition/timing systems. Microprocessor input/output boards are used to control and monitor the microwave circuitry and associated electronic devices. The implementation of the control system is based on an object-oriented client/server model: a centralized server manages the hardware and receives input from remote clients. Communication is handled through transmission control protocol/internet protocol sockets. Here we describe recent upgrades of the control system aiming to: (i) accommodate new channels; (ii) adapt to the heterogeneity of computing platforms and operating systems; and (iii) overcome remote access restrictions. Platform and operating system independence was achieved by redesigning the graphical user interface in JAVA. As secure shell is the standard remote access protocol adopted in major fusion laboratories, secure shell tunneling was implemented to allow remote operation of the diagnostic through the existing firewalls

  2. Upgrade to the control system of the reflectometry diagnostic of ASDEX upgrade

    Science.gov (United States)

    Graça, S.; Santos, J.; Manso, M. E.

    2004-10-01

    The broadband frequency modulation-continuous wave microwave/millimeter wave reflectometer of ASDEX upgrade tokamak (Institut für Plasma Physik (IPP), Garching, Germany) developed by Centro de Fusão Nuclear (Lisboa, Portugal) with the collaboration of IPP, is a complex system with 13 channels (O and X modes) and two types of operation modes (swept and fixed frequency). The control system that ensures remote operation of the diagnostic incorporates VME and CAMAC bus based acquisition/timing systems. Microprocessor input/output boards are used to control and monitor the microwave circuitry and associated electronic devices. The implementation of the control system is based on an object-oriented client/server model: a centralized server manages the hardware and receives input from remote clients. Communication is handled through transmission control protocol/internet protocol sockets. Here we describe recent upgrades of the control system aiming to: (i) accommodate new channels; (ii) adapt to the heterogeneity of computing platforms and operating systems; and (iii) overcome remote access restrictions. Platform and operating system independence was achieved by redesigning the graphical user interface in JAVA. As secure shell is the standard remote access protocol adopted in major fusion laboratories, secure shell tunneling was implemented to allow remote operation of the diagnostic through the existing firewalls.

  3. Tungsten transport in the plasma edge at ASDEX upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Janzer, Michael Arthur

    2015-04-30

    The Plasma Facing Components (PFC) will play a crucial role in future deuterium-tritium magnetically confined fusion power plants, since they will be subject to high energy and particle loads, but at the same time have to ensure long lifetimes and a low tritium retention. These requirements will most probably necessitate the use of high-Z materials such as tungsten for the wall materials, since their erosion properties are very benign and, unlike carbon, capture only little tritium. The drawback with high-Z materials is, that they emit strong line radiation in the core plasma, which acts as a powerful energy loss mechanism. Thus, the concentration of these high-Z materials has to be controlled and kept at low levels in order to achieve a burning plasma. Understanding the transport processes in the plasma edge is essential for applying the proper impurity control mechanisms. This control can be exerted either by enhancing the outflux, e.g. by Edge Localized Modes (ELM), since they are known to expel impurities from the main plasma, or by reducing the influx, e.g. minimizing the tungsten erosion or increasing the shielding effect of the Scrape Off Layer (SOL). ASDEX Upgrade (AUG) has been successfully operating with a full tungsten wall for several years now and offers the possibility to investigate these edge transport processes for tungsten. This study focused on the disentanglement of the frequency of type-I ELMs and the main chamber gas injection rate, two parameters which are usually linked in H-mode discharges. Such a separation allowed for the first time the direct assessment of the impact of each parameter on the tungsten concentration. The control of the ELM frequency was performed by adjusting the shape of the plasma, i.e. the upper triangularity. The radial tungsten transport was investigated by implementing a modulated tungsten source. To create this modulated source, the linear dependence of the tungsten erosion rate at the Ion Cyclotron Resonance

  4. New drive converter and digital control for the pulsed power supply system of ASDEX Upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Käsemann, Claus-Peter, E-mail: c.p.kaesemann@ipp.mpg.de [Max Planck Institute for Plasma Physics, Boltzmannstraße 2, 85748 Garching (Germany); Jacob, Christian; Nguyen, Hong Ha; Stobbe, Ferdinand; Mayer, Alois [Max Planck Institute for Plasma Physics, Boltzmannstraße 2, 85748 Garching (Germany); Sachs, Edgar; Klein, Reiner [Siemens AG, Industrial Automation Systems, Gleiwitzer Straße 555, 90475 Nürnberg (Germany)

    2015-10-15

    Highlights: • IGBT converter system with integrated control. • Proven technology reduces time and budget. • Flexibility to be integrated into a 35 years old installation. • Stable control algorithms for static and dynamic speed control. • Possibilities for active and reactive power management. - Abstract: Safety and reliability are major issues for the ASDEX Upgrade (AUG) pulsed power supply systems. To avoid long downtimes during an experimental campaign, fault-prone components have to be identified and treated early. This becomes even more important due to the AUG participation in the EUROfusion Medium Sized Tokamak (MST) program. Operating equipment which is up to 40 years old adds additional complications. This contribution describes one such example where a 35 year old flywheel generator at AUG was identified as fault-prone and pre-emptively upgraded with a new drive converter with integrated control. Most challenging was to adapt a modern converter, originally designed for wind turbines, toward a drive system for a flywheel-motor-generator system. To identify the layout of the controller and the control parameters, accurate modeling and comprehensive simulations were performed. This effort paid off during commissioning and measuring results verified the calculated design values. Finally, the system shows good performance during AUG plasma experiments.

  5. Plasma rotation and ion temperature measurements by collective Thomson scattering at ASDEX Upgrade

    DEFF Research Database (Denmark)

    Stejner Pedersen, Morten; Nielsen, Stefan Kragh; Jacobsen, Asger Schou

    2015-01-01

    We present the first deuterium ion temperature and rotation measurements by collective Thomson scattering at ASDEX Upgrade. The results are in general agreement with boron-based charge exchange recombination spectroscopy measurements and consistent with neoclassical simulations for the plasma sce...... scenario studied here. This demonstration opens the prospect for direct non-perturbative measurements of the properties of the main ion species in the plasma core with applications in plasma transport and confinement studies.......We present the first deuterium ion temperature and rotation measurements by collective Thomson scattering at ASDEX Upgrade. The results are in general agreement with boron-based charge exchange recombination spectroscopy measurements and consistent with neoclassical simulations for the plasma...

  6. Tungsten erosion and redeposition in the all-tungsten divertor of ASDEX Upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Mayer, M; Krieger, K; Matern, G; Neu, R; Rasinski, M; Rohde, V; Sugiyama, K; Wiltner, A [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, Boltzmannstrasse 2, 85748 Garching (Germany); Andrzejczuk, M; Fortuna-Zalesna, E; Kurzydlowski, K J; Zielinski, W [Faculty of Materials Science and Engineering, Warsaw University of Technology, Association EURATOM-IPPLM, 02-507 Warsaw (Poland); Hakola, A; Koivuranta, S; Likonen, J [VTT Materials for Power Engineering, EURATOM Association, PO Box 1000, FI-02044 VTT (Finland); Ramos, G [CICATA-Qro, Instituto Politecnico Nacional, Queretaro (Mexico); Dux, R, E-mail: matej.mayer@ipp.mpg.de

    2009-12-15

    Net erosion and deposition of tungsten (W) in the ASDEX Upgrade divertor were determined after the 2007 campaign by using thin W marker stripes. ASDEX Upgrade had full-W plasma-facing components during this campaign. The inner divertor and the roof baffle were net W deposition areas with a maximum deposition of about 1x10{sup 18} W-atoms cm{sup -2} in the private flux region below the inner strike point. Net erosion of W was observed in the whole outer divertor, with the largest erosion close to the outer strike point. Only a small fraction of the W eroded in the main chamber and in the outer divertor was found in redeposits in the inner divertor, while a large fraction was either redeposited at unidentified places in the main chamber or has formed dust.

  7. Results of high heat flux tests and structural analysis of the new solid tungsten divertor tile for ASDEX Upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Jaksic, Nikola, E-mail: nikola.jaksic@ipp.mpg.de; Greuner, Henri; Herrmann, Albrecht; Böswirth, Bernd; Vorbrugg, Stefan

    2015-10-15

    results from the operation in the ASDEX Upgrade experiment are presented.

  8. Results of high heat flux tests and structural analysis of the new solid tungsten divertor tile for ASDEX Upgrade

    International Nuclear Information System (INIS)

    Jaksic, Nikola; Greuner, Henri; Herrmann, Albrecht; Böswirth, Bernd; Vorbrugg, Stefan

    2015-01-01

    from the operation in the ASDEX Upgrade experiment are presented.

  9. Energy flux to the ASDEX-upgrade diverter plates determined by thermography and calorimetry

    International Nuclear Information System (INIS)

    Herrmann, A.; Junker, W.; Guenther, K.

    1995-01-01

    A new thermography system with high time resolution was put into operation at ASDEX-Upgrade and is routinely used to determine the energy flux onto the lower diverter plates. The measurements allow the power deposition to be characterized during dynamic events such as ELMs and disruptions, as well as the asymmetry of the inboard/outboard power load. A power balance is set up even during single discharges and the losses are found to be fairly equal to the power input. (author)

  10. Observations on the W-transport in the core plasma of JET and ASDEX Upgrade

    Czech Academy of Sciences Publication Activity Database

    Pütterich, T.; Dux, R.; Neu, R.; Bernert, M.; Beurskens, M.N.A.; Bobkov, V.; Brezinsek, S.; Challis, C.; Coenen, J.W.; Coffey, I.; Czarnecka, A.; Giroud, C.; Jacquet, P.; Joffrin, E.; Kallenbach, A.; Lehnen, M.; Lerche, E.; De La Luna, E.; Marsen, S.; Matthews, G.; Mayoral, M.-L.; McDermott, R.M.; Meigs, A.; Mlynář, Jan; Sertoli, M.; van Rooij, G.

    2013-01-01

    Roč. 55, č. 12 (2013), s. 124036-124036 ISSN 0741-3335. [European Physical Society Conference on Plasma Physics/40./. Espoo, 01.07.2013-05.07.2013] Institutional support: RVO:61389021 Keywords : tokamak * impurity transport * core plasma * fusion * tungsten * ASDEX Upgrade Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 2.386, year: 2013 http://iopscience.iop.org/0741-3335/55/12/124036/pdf/0741-3335_55_12_124036.pdf

  11. Radial transport of poloidal momentum in ASDEX Upgrade in L-mode and H-mode

    DEFF Research Database (Denmark)

    Schrittwieser, R.; Mehlmann, F.; Naulin, Volker

    2012-01-01

    A reciprocating probe was used for localized measurements of the radial transport of poloidal momentum in the scrape-off layer (SOL) of ASDEX Upgrade (AUG). The probe measured poloidal and radial electric field components and density. We concentrate on three components of the momentum transport: ......: Reynolds stress, convective momentum flux and triple product of the fluctuating components of density, radial and poloidal electric field. For the evaluation we draw mainly on the probability density functions (PDFs)....

  12. The new centrifuge high-speed pellet injector for ASDEX Upgrade

    International Nuclear Information System (INIS)

    Lang, P.T.; Andelfinger, C.; Beck, W.; Buchelt, E.; Buechl, K.; Cierpka, P.; Kollotzek, H.; Lang, R.S.; Prausner, G.; Soeldner, F.X.; Ulrich, M.; Weber, G.

    1993-04-01

    We report on the new pellet injection system for refuelling the ASDEX Upgrade tokamak with cubic H 2 or D 2 pellets having alternative side lengths of 1.5, 1.75 and 2.0 mm and optional Ne doping. The system delivers series of about one hundred pellets at a maximum repetition rate of more than 40 Hz. The pellets are accelerated by means of a centrifuge with an optimized straight acceleration arm. This configuration minimizes the compulsive force acting on the pellet during the acceleration process. Since this also minimizes stresses inside the pellet, high velocities - a maximum of 1211 m/s being achieved - are possible without destroying the hydrogen cubes. A special pellet feed-in technique based on a static stop cylinder interrupting the acceleration path successfully reduced the horizontal scattering angle to values of less than ± 4 degrees. Thus, a high efficiency - with more than 90% of the pellets arriving within the acceptance angle - was achieved without using a guide tube. The whole system was found to work very reliably and reproducibly during the whole test operation period, covering about 10 5 pellet shots. The new centrifuge, now integrated into the ASDEX Upgrade setup, has proved to be a reliable unit even for long operation periods thus affording the possibility of quasicontinuous particle refuelling throughout a plasma discharge in ASDEX Upgrade. (orig.)

  13. A cross-tokamak neural network disruption predictor for the JET and ASDEX Upgrade tokamaks

    Science.gov (United States)

    Windsor, C. G.; Pautasso, G.; Tichmann, C.; Buttery, R. J.; Hender, T. C.; EFDA Contributors, JET; ASDEX Upgrade Team

    2005-05-01

    First results are reported on the prediction of disruptions in one tokamak, based on neural networks trained on another tokamak. The studies use data from the JET and ASDEX Upgrade devices, with a neural network trained on just seven normalized plasma parameters. In this way, a simple single layer perceptron network trained solely on JET correctly anticipated 67% of disruptions on ASDEX Upgrade in advance of 0.01 s before the disruption. The converse test led to a 69% success rate in advance of 0.04 s before the disruption in JET. Only one overall time scaling parameter is allowed between the devices, which can be introduced from theoretical arguments. Disruption prediction performance based on such networks trained and tested on the same device shows even higher success rates (JET, 86%; ASDEX Upgrade, 90%), despite the small number of inputs used and simplicity of the network. It is found that while performance for networks trained and tested on the same device can be improved with more complex networks and many adjustable weights, for cross-machine testing the best approach is a simple single layer perceptron. This offers the basis of a potentially useful technique for large future devices such as ITER, which with further development might help to reduce disruption frequency and minimize the need for a large disruption campaign to train disruption avoidance systems.

  14. A cross-tokamak neural network disruption predictor for the JET and ASDEX Upgrade tokamaks

    International Nuclear Information System (INIS)

    Windsor, C.G.; Buttery, R.J.; Hender, T.C.; Pautasso, G.; Tichmann, C.

    2005-01-01

    First results are reported on the prediction of disruptions in one tokamak, based on neural networks trained on another tokamak. The studies use data from the JET and ASDEX Upgrade devices, with a neural network trained on just seven normalized plasma parameters. In this way, a simple single layer perceptron network trained solely on JET correctly anticipated 67% of disruptions on ASDEX Upgrade in advance of 0.01 s before the disruption. The converse test led to a 69% success rate in advance of 0.04 s before the disruption in JET. Only one overall time scaling parameter is allowed between the devices, which can be introduced from theoretical arguments. Disruption prediction performance based on such networks trained and tested on the same device shows even higher success rates (JET, 86%; ASDEX Upgrade, 90%), despite the small number of inputs used and simplicity of the network. It is found that while performance for networks trained and tested on the same device can be improved with more complex networks and many adjustable weights, for cross-machine testing the best approach is a simple single layer perceptron. This offers the basis of a potentially useful technique for large future devices such as ITER, which with further development might help to reduce disruption frequency and minimize the need for a large disruption campaign to train disruption avoidance systems

  15. ASDEX Upgrade-JT-60U comparison and ECRH power requirements for NTM stabilization in ITER

    International Nuclear Information System (INIS)

    Urso, L.; Zohm, H.; Maraschek, M.; Poli, E.; Isayama, A.

    2010-01-01

    Neoclassical tearing modes (NTMs) are experimentally controlled with local electron cyclotron current drive (ECCD) and the island width decay during NTM stabilization is modelled using the so-called modified Rutherford equation (MRE). In this paper, a modelling of the MRE is carried out and simulations of the island width decay are compared with the experimentally observed ones in order to fit the two free machine-independent parameters present in the equation. A systematic study on a database of NTM stabilization discharges from ASDEX Upgrade and JT-60U is done for extrapolating the ECCD power requirements for ITER. The extrapolation to ITER of the NTM stabilization results from ASDEX Upgrade and JT-60U shows that 10 MW of ECCD power are enough to stabilize large NTMs. The 10 MW power estimate for ITER is based on the assumption that the free parameters in the MRE are machine independent. Indeed, this assumption is verified in this paper for ASDEX Upgrade and JT-60U. An interesting consequence of the relatively modest power requirement for ITER is that the installed 20 MW will suffice for simultaneous 2/1 and 3/2 NTM stabilization.

  16. Empiricial scaling of inter-ELM power widths in ASDEX Upgrade and JET

    Energy Technology Data Exchange (ETDEWEB)

    Eich, T., E-mail: teich@ipp.mpg.de [Max-Planck-Institut für Plasmaphysik, EURATOM Association, Boltzmannstr. 2, D-85748 Garching (Germany); Sieglin, B.; Scarabosio, A.; Herrmann, A.; Kallenbach, A. [Max-Planck-Institut für Plasmaphysik, EURATOM Association, Boltzmannstr. 2, D-85748 Garching (Germany); Matthews, G.F. [EURATOM/CCFE Association, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Jachmich, S. [ERM-KMS, EURATOM Association, Brussels (Belgium); Brezinsek, S.; Rack, M. [IEK-4, Forschungszentrum Jülich, EURATOM Association (Germany); Goldston, R.J. [Princeton Plasma Physics Labaratory, Princeton, NJ 08543 (United States)

    2013-07-15

    The SOL power decay length (λ{sub q}) deduced from analysis of fully attached divertor heat load profiles from two tokamaks, JET and ASDEX Upgrade with carbon plasma facing components, are presented. Interpretation of the target heat load profiles is performed by using a 1D-fit function which disentangles the upstream λ{sub q} and an effective diffusion in the divertor (S), the latter essentially acting as a power spreading parameter in the divertor volume. It is shown that the so called integral decay length λ{sub int} is approximately given by λ{sub int}≈λ{sub q}+1.64×S. An empirical scaling reveals parametric dependency λ{sub q}/mm≃0.9·B{sub T}{sup -0.7}q{sub cyl}{sup 1.2}P{sub SOL}{sup 0}R{sub geo}{sup 0} for type-I ELMy H-modes. Extrapolation to ITER gives λ{sub q}≃1 mm. Recent measurements in JET-ILW and from ASDEX Upgrade full-W confirm the results. It is shown that a regression for the divertor power spreading parameter S is not yet possible due to the large effect of different divertor geometries of JET and ASDEX Upgrade Divertor-I and Divertor-IIb.

  17. Investigation of transient melting of tungsten by ELMs in ASDEX Upgrade

    International Nuclear Information System (INIS)

    Krieger, K; Sieglin, B; Balden, M; De Marne, P; Nille, D; Rohde, V; Faitsch, M; Giannone, L; Herrmann, A; Coenen, J W; Göths, B; Laggner, F; Matthews, G F; Dejarnac, R; Horacek, J; Komm, M; Pitts, R A; Ratynskaia, S; Thoren, E; Tolias, P

    2017-01-01

    Repetitive melting of tungsten by power transients originating from edge localized modes (ELMs) has been studied in the tokamak experiment ASDEX Upgrade. Tungsten samples were exposed to H-mode discharges at the outer divertor target plate using the Divertor Manipulator II system. The exposed sample was designed with an elevated sloped surface inclined against the incident magnetic field to increase the projected parallel power flux to a level were transient melting by ELMs would occur. Sample exposure was controlled by moving the outer strike point to the sample location. As extension to previous melt studies in the new experiment both the current flow from the sample to vessel potential and the local surface temperature were measured with sufficient time resolution to resolve individual ELMs. The experiment provided for the first time a direct link of current flow and surface temperature during transient ELM events. This allows to further constrain the MEMOS melt motion code predictions and to improve the validation of its underlying model assumptions. Post exposure ex situ analysis of the retrieved samples confirms the decreased melt motion observed at shallower magnetic field line to surface angles compared to that at leading edges exposed to the parallel power flux. (paper)

  18. Migration and deposition of 13C in the full-tungsten ASDEX Upgrade tokamak

    International Nuclear Information System (INIS)

    Hakola, A; Aho-Mantila, L; Groth, M; Kurki-Suonio, T; Makkonen, T; Likonen, J; Koivuranta, S; Krieger, K; Mayer, M; Mueller, H W; Neu, R; Rohde, V

    2010-01-01

    The migration of carbon in low-density, low-confinement plasmas of ASDEX Upgrade was studied by injecting 13 C into the main chamber of the torus at the end of the 2007 experimental campaign. A selection of standard tungsten-coated lower-divertor and main-chamber tiles as well as a complete set of lower-divertor tiles with an uncoated poloidal marker stripe were removed from one poloidal cross section and analysed using secondary ion mass spectrometry. The poloidal deposition profiles of 13 C on both the tungsten-coated tiles and on the uncoated graphite areas of the marker tiles were measured and compared. For the W-coated lower-divertor tiles, 13 C was deposited mainly on the high-field side tiles, while barely detectable amounts of 13 C were observed on low-field side samples. In contrast, on the uncoated marker stripes the deposition was equally pronounced in the high-field and low-field side divertor. The marker-tile results are in agreement with those obtained from graphite tiles after the 2003 and 2005 13 C experiments in ASDEX Upgrade. In the case of W-coated tiles, the 13 C measurements were complemented by determining the total amount of deposited carbon ( 12 C) on the tiles, which also shows strong deposition at the inner parts of the lower divertor. The estimated deposition of 13 C on W at the divertor areas was less than 1.5% of the injected amount of 13 C atoms. The 13 C analyses of the main-chamber tiles and small silicon samples mounted in remote areas revealed significant deposition in the upper divertor, in upper parts of the heat shield, in the limiter region close to the injection valve, and below the roof baffle. Approximately 8% of the injected 13 C is estimated to have accumulated in these regions. Possible reasons for the different deposition patterns on W and on graphite in different regions of the torus are discussed.

  19. Experimental studies of high-confinement mode plasma response to non-axisymmetric magnetic perturbations in ASDEX Upgrade

    Science.gov (United States)

    Suttrop, W.; Kirk, A.; Nazikian, R.; Leuthold, N.; Strumberger, E.; Willensdorfer, M.; Cavedon, M.; Dunne, M.; Fischer, R.; Fietz, S.; Fuchs, J. C.; Liu, Y. Q.; McDermott, R. M.; Orain, F.; Ryan, D. A.; Viezzer, E.; The ASDEX Upgrade Team; The DIII-D Team; The Eurofusion MST1 Team

    2017-01-01

    The interaction of externally applied small non-axisymmetric magnetic perturbations (MP) with tokamak high-confinement mode (H-mode) plasmas is reviewed and illustrated by recent experiments in ASDEX Upgrade. The plasma response to the vacuum MP field is amplified by stable ideal kink modes with low toroidal mode number n driven by the H-mode edge pressure gradient (and associated bootstrap current) which is experimentally evidenced by an observable shift of the poloidal mode number m away from field alignment (m  =  qn, with q being the safety factor) at the response maximum. A torque scan experiment demonstrates the importance of the perpendicular electron flow for shielding of the resonant magnetic perturbation, as expected from a two-fluid MHD picture. Two significant effects of MP occur in H-mode plasmas at low pedestal collisionality, ν \\text{ped}\\ast≤slant 0.4 : (a) a reduction of the global plasma density by up to 61 % and (b) a reduction of the energy loss associated with edge localised modes (ELMs) by a factor of up to 9. A comprehensive database of ELM mitigation pulses at low {ν\\ast} in ASDEX Upgrade shows that the degree of ELM mitigation correlates with the reduction of pedestal pressure which in turn is limited and defined by the onset of ELMs, i. e. a modification of the ELM stability limit by the magnetic perturbation.

  20. FEM investigation and thermo-mechanic tests of the new solid tungsten divertor tile for ASDEX Upgrade

    International Nuclear Information System (INIS)

    Jaksic, Nikola; Greuner, Henri; Herrmann, Albrecht

    2013-01-01

    Highlights: • New solid tungsten divertor for fusion experiment ASDEX Upgrade. • Design validation in the high heat flux (HHF) test facility GLADIS (Garching Large Divertor Sample Test Facility). • FEA simulation. -- Abstract: A new solid tungsten divertor for the fusion experiment ASDEX Upgrade is under construction at present. A new divertor tile design has been developed to improve the thermal performance of the current divertor made of tungsten coated fine grain graphite. Compared to thin tungsten coatings, divertor tiles made of massive tungsten allow to extend the operational range and to study the plasma material interaction of tungsten in more detail. The improved design for the solid tungsten divertor was tested on different full scale prototypes with a hydrogen ion beam. The influence of a possible material degradation due to thermal cracking or recrystallization can be studied. Furthermore, intensive Finite Element Method (FEM) numerical analysis with the respective test parameters has been performed. The elastic–plastic calculation was applied to analyze thermal stress and the observed elastic and plastic deformation during the heat loading. Additionally, the knowledge gained by the tests and especially by the numerical analysis has been used to optimize the shape of the divertor tiles and the accompanying divertor support structure. This paper discusses the main results of the high heat flux tests and their numerical simulations. In addition, results from some special structural mechanic analysis by means of FEM tools are presented. Finally, first results from the numerical lifecycle analysis of the current tungsten tiles will be reported

  1. Review of the ASDEX upgrade data acquisition environment - present operation and future requirements

    International Nuclear Information System (INIS)

    Behler, K.; Blank, H.; Buhler, A.; Drube, R.; Friedrich, H.; Foerster, K.; Hallatschek, K.; Heimann, P.; Hertweck, F.; Maier, J.; Heimann, R.; Hertweck, F.; Maier, J.; Merkel, R.; Pacco-Duechs, M.-G.; Raupp, G.; Reuter, H.; Schneider-Maxon, U.; Tisma, R.; Zilker, M.

    1999-01-01

    The data acquisition environment of the ASDEX upgrade fusion experiment was designed in the late 1980s to handle a predicted quantity of 8 Mbytes fo data per discharge. After 7 years of operation a review of the whole data acquisition and analysis environment shows what remains of the original design ideas. Comparing the original 15 diagnostics with the present set of 250 diagnostic datasets generated per shot shows how the system has grown. Although now a vast accumulation of functional parts, the system still works in a stable manner and is maintainable. The underlying concepts affirming these qualities are modularity and compatibility. Modularity ensures that most parts of the system can be modified without affecting others. Standards for data structures and interfaces between components and methods are the prerequisites which make modularity work. The experience of the last few years shows that, besides the standards achieved, new, mainly real-time, features are needed: real-time event recognition allowing reaction to complex changing conditions; real-time wavelet analysis allowing adapted sampling rates; real-time data exchange between diagnostics and control; real-time networks allowing flexible computer coupling to permit interplay between different components; object-oriented programming concepts and databases are required for readily adaptable software modules. A final assessment of our present data processing situation and future requirements shows that modern information technology methods have to be applied more intensively to provide the most flexible means to improve the interaction of all components on a large fusion device. (orig.)

  2. Global gyrokinetic simulations of intrinsic rotation in ASDEX Upgrade Ohmic L-mode plasmas

    Science.gov (United States)

    Hornsby, W. A.; Angioni, C.; Lu, Z. X.; Fable, E.; Erofeev, I.; McDermott, R.; Medvedeva, A.; Lebschy, A.; Peeters, A. G.; The ASDEX Upgrade Team

    2018-05-01

    Non-linear, radially global, turbulence simulations of ASDEX Upgrade (AUG) plasmas are performed and the nonlinear generated intrinsic flow shows agreement with the intrinsic flow gradients measured in the core of Ohmic L-mode plasmas at nominal parameters. Simulations utilising the kinetic electron model show hollow intrinsic flow profiles as seen in a predominant number of experiments performed at similar plasma parameters. In addition, significantly larger flow gradients are seen than in a previous flux-tube analysis (Hornsby et al 2017 Nucl. Fusion 57 046008). Adiabatic electron model simulations can show a flow profile with opposing sign in the gradient with respect to a kinetic electron simulation, implying a reversal in the sign of the residual stress due to kinetic electrons. The shaping of the intrinsic flow is strongly determined by the density gradient profile. The sensitivity of the residual stress to variations in density profile curvature is calculated and seen to be significantly stronger than to neoclassical flows (Hornsby et al 2017 Nucl. Fusion 57 046008). This variation is strong enough on its own to explain the large variations in the intrinsic flow gradients seen in some AUG experiments. Analysis of the symmetry breaking properties of the turbulence shows that profile shearing is the dominant mechanism in producing a finite parallel wave-number, with turbulence gradient effects contributing a smaller portion of the parallel wave-vector.

  3. Correlation electron cyclotron emission diagnostic and improved calculation of turbulent temperature fluctuation levels on ASDEX Upgrade

    Science.gov (United States)

    Creely, A. J.; Freethy, S. J.; Burke, W. M.; Conway, G. D.; Leccacorvi, R.; Parkin, W. C.; Terry, D. R.; White, A. E.

    2018-05-01

    A newly upgraded correlation electron cyclotron emission (CECE) diagnostic has been installed on the ASDEX Upgrade tokamak and has begun to perform experimental measurements of electron temperature fluctuations. CECE diagnostics measure small amplitude electron temperature fluctuations by correlating closely spaced heterodyne radiometer channels. This upgrade expanded the system from six channels to thirty, allowing simultaneous measurement of fluctuation level radial profiles without repeat discharges, as well as opening up the possibility of measuring radial turbulent correlation lengths. Newly refined statistical techniques have been developed in order to accurately analyze the fluctuation data collected from the CECE system. This paper presents the hardware upgrades for this system and the analysis techniques used to interpret the raw data, as well as measurements of fluctuation spectra and fluctuation level radial profiles.

  4. Impact of lithium on the plasma performance in the all-metal-wall tokamak ASDEX upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Lang, P.T.; Moreno Quicios, R.; Arredondo Parra, R.; Ploeckl, B.; McDermott, R.; Neu, R.; Wolfrum, E. [MPI fuer Plasmaphysik, Boltzmannstr. 2, 85748 Garching (Germany); Maingi, R.; Mansfield, D.K.; Diallo, A. [Princeton Plasma Physics Laboratory, Princeton, NJ 08543 (United States); Collaboration: ASDEX Upgrade Team

    2016-07-01

    Several tokamaks reported improvement in key plasma parameters concurrent with the presence of lithium in the plasma. At ASDEX Upgrade explorative experiments have been performed to find out if such effects can be observed when operating with an all-metal-wall. A gas gun launcher was developed capable to inject pellets containing about 1.6 x 10{sup 20} Li atoms at 2 Hz. The speed of about 600 m/s is sufficient to achieve core penetration and to create a homogeneous Li concentration of up to 10 %. With a typical sustainment time on the order of 100 ms, only transient Li presence without any pile up was achieved. Deposition of Li on plasma facing components, which remained for several discharges after injection, was observed. This short lived wall conditioning showed beneficial effects during plasma start-up. However, the accompanying surface contamination negatively impacted some diagnostics. The Li impact on the confinement was investigated in a dedicated plasma scenario with a proven sensitivity to nitrogen and helium. In phases with N seeding enhancing the confinement by about 30 %, Li injection resulted in a very modest, transient loss of confinement (about 5 %). No Li impact was found for pure Deuterium plasmas.

  5. Operation of ICRF antennas in a full tungsten environment in ASDEX Upgrade

    Science.gov (United States)

    Bobkov, Vl.; Braun, F.; Dux, R.; Giannone, L.; Herrmann, A.; Kallenbach, A.; Müller, H. W.; Neu, R.; Noterdaeme, J.-M.; Pütterich, Th.; Rohde, V.; ASDEX Upgrade Team

    2009-06-01

    In the 2007 and early part of 2008 experimental campaigns, ASDEX Upgrade operated with full tungsten (W) wall without boronization. Use of ICRF power results in a significant increase of W source. Low temperature conditions at the plasma facing components, achieved by a large clearance between the separatrix and the antenna (>6 cm) and by elevated gas puff rates (>5×1021 s) help to lower W sputtering yield during ICRF. Operation of neighboring ICRF antennas at the phase difference close to -90° can lead to a reduction in the W source. However, a reduction of parallel near-fields by antenna design is needed to further minimize the W source. A relation has been established between the HFSS code calculations predicting a dominant role of box currents in the formation of parallel antenna near-fields and the experiment. The shapes of the measured vertical profile of effective sputtering yields and the calculated sheath driving voltages show a qualitative agreement. This confirms that the existing tools are a good basis to design an improved antenna.

  6. Poloidal structure of the plasma response to n = 1 Resonant Magnetic Perturbations in ASDEX Upgrade

    Science.gov (United States)

    Marrelli, L.; Bettini, P.; Piovesan, P.; Terranova, D.; Giannone, L.; Igochine, V.; Maraschek, M.; Suttrop, W.; Teschke, M.; Liu, Y. Q.; Ryan, D.; Eurofusion Mst1 Team; ASDEX Upgrade Team

    2017-10-01

    The hybrid scenario, a candidate for high-beta steady-state tokamak operations, becomes highly sensitive to 3D magnetic field near the no-wall limit. A predictive understanding of the plasma response to 3D fields near ideal MHD limits in terms of validated MHD stability codes is therefore important in order to safely operate future devices. Slowly rotating (5 - 10 Hz) n = 1 external magnetic fields have been applied in hybrid discharges in ASDEX Upgrade for an experimental characterization: the global n = 1 kink response has been measured by means of SXR and complete poloidal arrays of bθ probes located at different toroidal angles and compared to predictions of MHD codes such as MARS-F and V3FIT-VMEC. A Least-Squares Spectral Analysis approach has been developed together with a Monte Carlo technique to extract the small plasma response and its confidence interval from the noisy magnetic signals. MARS-F correctly reproduces the poloidal structure of the n = 1 measurements: for example, the dependence of the dominant poloidal mode number at the plasma edge from q95 is the same as in the experiment. Similar comparisons with V3FIT-VMEC and will be presented. See author list of ``H. Meyer et al. 2017 Nucl. Fusion 57 102014''.

  7. Operation of ICRF antennas in a full tungsten environment in ASDEX Upgrade

    International Nuclear Information System (INIS)

    Bobkov, Vl.; Braun, F.; Dux, R.; Giannone, L.; Herrmann, A.; Kallenbach, A.; Mueller, H.W.; Neu, R.; Noterdaeme, J.-M.; Puetterich, Th.; Rohde, V.

    2009-01-01

    In the 2007 and early part of 2008 experimental campaigns, ASDEX Upgrade operated with full tungsten (W) wall without boronization. Use of ICRF power results in a significant increase of W source. Low temperature conditions at the plasma facing components, achieved by a large clearance between the separatrix and the antenna (>6 cm) and by elevated gas puff rates (>5x10 21 s -1 ) help to lower W sputtering yield during ICRF. Operation of neighboring ICRF antennas at the phase difference close to -90 deg. can lead to a reduction in the W source. However, a reduction of parallel near-fields by antenna design is needed to further minimize the W source. A relation has been established between the HFSS code calculations predicting a dominant role of box currents in the formation of parallel antenna near-fields and the experiment. The shapes of the measured vertical profile of effective sputtering yields and the calculated sheath driving voltages show a qualitative agreement. This confirms that the existing tools are a good basis to design an improved antenna.

  8. A new compact solid-state neutral particle analyser at ASDEX Upgrade: Setup and physics modeling

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, P. A.; Blank, H.; Geiger, B.; Mank, K.; Martinov, S.; Ryter, F.; Weiland, M.; Weller, A. [Max-Planck-Institut für Plasmaphysik, Garching (Germany)

    2015-07-15

    At ASDEX Upgrade (AUG), a new compact solid-state detector has been installed to measure the energy spectrum of fast neutrals based on the principle described by Shinohara et al. [Rev. Sci. Instrum. 75, 3640 (2004)]. The diagnostic relies on the usual charge exchange of supra-thermal fast-ions with neutrals in the plasma. Therefore, the measured energy spectra directly correspond to those of confined fast-ions with a pitch angle defined by the line of sight of the detector. Experiments in AUG showed the good signal to noise characteristics of the detector. It is energy calibrated and can measure energies of 40-200 keV with count rates of up to 140 kcps. The detector has an active view on one of the heating beams. The heating beam increases the neutral density locally; thereby, information about the central fast-ion velocity distribution is obtained. The measured fluxes are modeled with a newly developed module for the 3D Monte Carlo code F90FIDASIM [Geiger et al., Plasma Phys. Controlled Fusion 53, 65010 (2011)]. The modeling allows to distinguish between the active (beam) and passive contributions to the signal. Thereby, the birth profile of the measured fast neutrals can be reconstructed. This model reproduces the measured energy spectra with good accuracy when the passive contribution is taken into account.

  9. Density response to central electron heating: theoretical investigations and experimental observations in ASDEX Upgrade

    Science.gov (United States)

    Angioni, C.; Peeters, A. G.; Garbet, X.; Manini, A.; Ryter, F.; ASDEX Upgrade Team

    2004-08-01

    Theory of ion temperature gradient (ITG) and trapped electron modes (TEMs) is applied to the study of particle transport in experimental conditions with central electron heating. It is shown that in the unstable domain of TEMs, the electron thermodiffusive flux is directed outwards. By means of such a flux, a mechanism is identified likely to account for density flattening with central electron heating. Theoretical predictions are compared with experimental observations in ASDEX Upgrade. A parameter domain (including L- and H-mode plasmas) is identified, in which flattening with central electron heating is observed in the experiments. In general, this domain turns out to be the same domain in which the dominant plasma instability is a TEM. On the contrary, the dominant instability is an ITG in plasmas whose density profile is not affected significantly by central electron heating. The flattening predicted by quasi-linear theory for low density L-mode plasmas is too small compared to the experimental observations. At very high density, even when the dominant instability is an ITG, electron heating can provide density flattening, via the coupling with the ion heat channel. In these conditions the anomalous diffusivity increases in response to the increased ion heat flux, while the large collisionality makes the anomalous pinch small and the Ware pinch important.

  10. Confinement and transport properties during current ramps in the ASDEX Upgrade tokamak

    Science.gov (United States)

    Fable, E.; Angioni, C.; Hobirk, J.; Pereverzev, G.; Fietz, S.; Hein, T.; ASDEX Upgrade Team

    2011-04-01

    A detailed analysis of experimental data from the ASDEX Upgrade tokamak is carried out to shed light on the properties of confinement and transport in the current ramp-up and ramp-down phases of the plasma discharge. The experimental database is used to identify the relevant ranges of parameters explored during the ramp-up and the ramp-down. The energy confinement time observed in the two ramps displays interesting evolution, in many cases attaining different values at the same current level between ramp-up and ramp-down. The possible reasons for this behaviour are investigated. Interpretative transport simulations are used as a tool to clarify the interplay between different parameters, which are coupled in a non-linear way. In addition, a theory-based transport model is used to understand the behaviour of confinement as observed in the experiment, evidencing the role of both turbulent and neoclassical transport. Linear gyrokinetic calculations are performed to identify the relevant turbulence regime, showing that a broad range of frequencies, in the trapped electron modes (TEMs) and in the ion temperature gradient modes (ITGs) regimes, is explored during both the ramp-up and ramp-down. In the same framework, a quasi-linear model is applied to calculate the value of the local logarithmic density gradient and compare it with the experimental value. Finally, first non-linear simulations of heat transport during the current ramps are presented.

  11. Enhancement of the FIDA diagnostic at ASDEX Upgrade for velocity space tomography

    DEFF Research Database (Denmark)

    Weiland, M.; Geiger, B.; Jacobsen, Asger Schou

    2016-01-01

    Recent upgrades to the FIDA (fast-ion D-alpha) diagnostic at ASDEX Upgrade are discussed. The diagnostic has been extended from three to five line of sight arrays with different angles to the magnetic field, and a spectrometer redesign allows the simultaneous measurement of red- and blue-shifted ......Recent upgrades to the FIDA (fast-ion D-alpha) diagnostic at ASDEX Upgrade are discussed. The diagnostic has been extended from three to five line of sight arrays with different angles to the magnetic field, and a spectrometer redesign allows the simultaneous measurement of red- and blue......-shifted parts of the Doppler spectrum. These improvements make it possible to reconstruct the 2D fast-ion velocity distribution from the FIDA measurements by tomographic inversion under a wide range of plasma parameters. Two applications of the tomography are presented: a comparison between the distributions...... resulting from 60 keV and 93 keV neutral beam injection and a velocity-space resolved study of fast-ion redistribution induced by a sawtooth crash inside and outside the sawtooth inversion radius....

  12. Calculation of the electromagnetic forces on the ASDEX upgrade vacuum vessel on disruption of the plasma current

    International Nuclear Information System (INIS)

    Preis, H.

    1986-01-01

    This study investigates the magnetic field diffusion through the vacuum vessel of the ASDEX Upgrade tokamak that occurs on sudden disruption of the plasma current. Eddy currents are thereby produced in the vessel wall. Their time behaviour and distribution are determined. Furthermore, the vessel is permeated by various magnetic fields which, together with the eddy currents, exert magnetic forces in the vessel wall. These are also calculated. These numerical analyses are performed for two of the modes of operation envisaged for ASDEX Upgrade: the so-called limiter and single-null magnetic field configurations. (orig.)

  13. Interpretation of fast measurements of plasma potential, temperature and density in SOL of ASDEX Upgrade

    Czech Academy of Sciences Publication Activity Database

    Horáček, Jan; Adámek, Jiří; Müller, H. W.; Seidl, J.; Nielsen, A.H.; Rohde, V.; Mehlmann, F.; Ionita, C.; Havlíčková, Eva

    2010-01-01

    Roč. 50, č. 10 (2010), s. 105001-105001 ISSN 0029-5515 R&D Projects: GA AV ČR KJB100430901; GA ČR GA202/09/1467; GA MŠk 7G09042 Institutional research plan: CEZ:AV0Z20430508 Keywords : Ball- pen probe * Langmuir probe * tokamak * plasma * SOL * turbulence * blob * interchange instability * ASDEX Upgrade Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 3.303, year: 2010 http://iopscience.iop.org/0029-5515/50/10/105001

  14. Fast-ion transport and neutral beam current drive in ASDEX upgrade

    DEFF Research Database (Denmark)

    Geiger, B.; Weiland, M.; Jacobsen, Asger Schou

    2015-01-01

    The neutral beam current drive efficiency has been investigated in the ASDEX Upgrade tokamak by replacing on-axis neutral beams with tangential off-axis beams. A clear modification of the radial fast-ion profiles is observed with a fast-ion D-alpha diagnostic that measures centrally peaked profiles...... during on-axis injection and outwards shifted profiles during off-axis injection. Due to this change of the fast-ion population, a clear modification of the plasma current profile is predicted but not observed by a motional Stark effect diagnostic. The fast-ion transport caused by MHD activity has been...

  15. Comparison of the filament behaviour observed during type I ELMs in ASDEX upgrade and MAST

    International Nuclear Information System (INIS)

    Kirk, A; Ayed, B; Counsell, G F; Lisgo, S; Price, M; Tallents, S; Herrmann, A; Eich, T; Muller, H W; Schmid, A; Wilson, H

    2008-01-01

    A study of the evolution of the filaments observed during Type I ELMs on ASDEX Upgrade and MAST is presented. The filaments start off rotating toroidally/poloidally with velocities close to that of the pedestal. This velocity then decreases as the filaments propagate radially. On both devices the ion saturation current e-folding lengths of the filaments show a weak, if any, dependence on the size of the ELM (δW ELM /W ped ). On MAST the measured radial velocities of the filaments also show at most a weak dependence on δW ELM /W ped

  16. Interpretation of fast measurements of plasma potential, temperature and density in SOL of ASDEX Upgrade

    DEFF Research Database (Denmark)

    Horacek, J.; Adamek, J.; Müller, H.W.

    2010-01-01

    This paper focuses on interpretation of fast (1 µs) and local (2–4 mm) measurements of plasma density, potential and electron temperature in the edge plasma of tokamak ASDEX Upgrade. Steady-state radial profiles demonstrate the credibility of the ball-pen probe. We demonstrate that floating...... potential fluctuations measured by a Langmuir probe are dominated by plasma electron temperature rather than potential. Spatial and temporal scales are found consistent with expectations based on interchange-driven turbulence. Conditionally averaged signals found for both potential and density are also...

  17. Intermittent transport across the scrape-off layer: latest results from ASDEX Upgrade

    Czech Academy of Sciences Publication Activity Database

    Kočan, M.; Müller, H.W.; Nold, B.; Lunt, T.; Adámek, Jiří; Allan, S.Y.; Bernert, M.; Conway, G.D.; de Marné, P.; Eich, T.; Elmore, S.; Gennrich, F.P.; Herrmann, A.; Horáček, Jan; Huang, Z.; Kallenbach, A.; Komm, Michael; Maraschek, M.; Mehlmann, F.; Müller, S.; Ribeiro, T.T.; Rohde, V.; Schrittwieser, R.; Scott, B.; Stroth, U.; Suttrop, W.; Wolfrum, E.

    2013-01-01

    Roč. 53, č. 7 (2013), 073047-073047 ISSN 0029-5515 R&D Projects: GA MŠk(CZ) LG11018; GA ČR(CZ) GAP205/12/2327; GA ČR GA202/09/1467 Institutional support: RVO:61389021 Keywords : ASDEX Upgrade scrape-off layer * plasma * tokamak * edge-localized mode (ELM) Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 3.243, year: 2013 http://iopscience.iop.org/0029-5515/53/7/073047/pdf/0029-5515_53_7_073047.pdf

  18. Particle influx measurements with the ASDEX-upgrade multichord visible spectroscopy system

    International Nuclear Information System (INIS)

    Kallenbach, A.; Mayer, H.M.; Schneider, W.

    1992-01-01

    This report describes the hardware and software components of the ASDEX-Upgrade multichord visible spectroscopy system. Main emphasis is laid on a detailed description of the detector, a free programmable charge-coupled device intensified by a microchannel plate. As an experimental application, flux measurements of different impurity species from the inner heat shield are presented. Poloidal profiles of the released impurity amount obtained for various experimental situations are used to check the plasma position which is derived by the function parametrization analysis. (orig.)

  19. Commissioning of inline ECE system within waveguide based ECRH transmission systems on ASDEX upgrade

    Directory of Open Access Journals (Sweden)

    Donné A.J.H.

    2012-09-01

    Full Text Available A CW capable inline electron cyclotron emission (ECE separation system for feedback control, featuring oversized corrugated waveguides, is commissioned on ASDEX upgrade (AUG. The system is based on a combination of a polarization independent, non-resonant, Mach-Zehnder diplexer equipped with dielectric plate beam splitters [2, 3] employed as corrugated oversized waveguide filter, and a resonant Fast Directional Switch, FADIS [4, 5, 6, 7] as ECE/ECCD separation system. This paper presents an overview of the system, the low power characterisation tests and first high power commissioning on AUG.

  20. Spatial radiation profiles in the ASDEX Upgrade divertor for detached plasmas

    International Nuclear Information System (INIS)

    Wenzel, U.; Thoma, A.; Dux, R.; Fuchs, C.; Herrmann, A.; Hirsch, S.; Kallenbach, A.; Kastelewicz, H.; Laux, M.; Mast, F.; Napiontek, B.

    1997-01-01

    In this paper we describe impurity line emission measurements in the divertor of ASDEX Upgrade during high power neutral beam heated discharges. We focus on detached conditions where the dominating part of the radiation comes from the X-point region. Spatially resolved line emission in the VUV and visible spectral region of the intrinsic carbon and additionally puffed impurities (neon and nitrogen) is presented. A simple interpretation of the line emission profiles is given and they are also compared to the results of bolometry. (orig.)

  1. Magnetic diagnostic of SOL-filaments generated by type I ELMs on JET and ASDEX Upgrade

    DEFF Research Database (Denmark)

    Naulin, Volker; Vianello, N.; Schrittwieser, R.

    2011-01-01

    to a simple model, motivated by observations. A new diagnostic in the form of a reciprocating probe with three magnetic pickup loops was developed for ASDEX Upgrade (AUG). Measurements during the passage of type-I ELM filaments determine the filaments to be in the scrape off layer (SOL) and to carry currents......This contribution is focused on the magnetic signatures of type I ELM filaments. On JET a limited number of high time resolution magnetic coils were used to derive essential ELM filament parameters. The method uses forward modelling and simultaneous fitting of magnetic pickup coil signals...

  2. H-mode confinement properties close to the power threshold in ASDEX Upgrade

    International Nuclear Information System (INIS)

    Ryter, F; Fuchs, J; Schneider, W; Sips, A; Staebler, A; Stober, J

    2008-01-01

    Confinement properties close to the H-mode power threshold are studied in the ASDEX Upgrade tokamak. The results show that good confinement can be obtained close to the threshold with Type-I ELMs. The existence of Type-I ELMs does not necessarily require the heating power to be higher than the H-Mode power threshold, but it requires collisionality to be low enough. At higher collisionality Type-III ELMs replace the Type-I ELMs and confinement time is reduced by about 20%

  3. Commissioning of inline ECE system within waveguide based ECRH transmission systems on ASDEX upgrade

    Science.gov (United States)

    Bongers, W. A.; Kasparek, W.; Doelman, N.; van den Braber, R.; van den Brand, H.; Meo, F.; de Baar, M. R.; Amerongen, F. J.; Donné, A. J. H.; Elzendoorn, B. S. Q.; Erckmann, V.; Goede, A. P. H.; Giannone, L.; Grünwald, G.; Hollman, F.; Kaas, G.; Krijger, B.; Michel, G.; Lubyako, L.; Monaco, F.; Noke, F.; Petelin, M.; Plaum, B.; Purps, F.; ten Pierik, J. G. W.; Schüller, C.; Slob, J. W.; Stober, J. K.; Schütz, H.; Wagner, D.; Westerhof, E.; Ronden, D. M. S.

    2012-09-01

    A CW capable inline electron cyclotron emission (ECE) separation system for feedback control, featuring oversized corrugated waveguides, is commissioned on ASDEX upgrade (AUG). The system is based on a combination of a polarization independent, non-resonant, Mach-Zehnder diplexer equipped with dielectric plate beam splitters [2, 3] employed as corrugated oversized waveguide filter, and a resonant Fast Directional Switch, FADIS [4, 5, 6, 7] as ECE/ECCD separation system. This paper presents an overview of the system, the low power characterisation tests and first high power commissioning on AUG.

  4. Electrical design of the BUSSARD inverter system for ASDEX upgrade saddle coils

    Energy Technology Data Exchange (ETDEWEB)

    Teschke, Markus, E-mail: teschke@ipp.mpg.de; Arden, Nils; Eixenberger, Horst; Rott, Michael; Suttrop, Wolfgang

    2015-10-15

    Highlights: • A cost effective inverter topology for AUG's 16 in-vessel saddle coils has been found. • Use of commercially available power modules is possible. • A NPC-like topology of the power stage is realized in a modular way. • The high-speed controllers and PWM engines are realized on Linux-based systems. • First experimental results of AUG plasma shots are presented. - Abstract: A set of 16 in-vessel saddle coils is installed in the ASDEX Upgrade (AUG) nuclear fusion experiment for mitigation of edge localized modes (ELM) and feedback control of resistive wall modes (RWM). The coils were driven by DC current only during previous campaigns. Now, a new inverter system “BUSSARD” (German abbr. for “Bayerischer Umrichter, schnell schaltend für AUGs rasche Drehfelder”, translated: “bavarian fast switching inverter for AUG's fast rotating fields”) is built for the experiment. A four-phase system has been assembled to simultaneously operate up to 4 groups of coils consisting of up to 4 serial-connected coils each. The maximum current is 1.3 kA with a ripple in the range of 7% and the frequency is variable between DC and approx. 100 Hz. The switching frequency is variable between approximately 3 and 10 kHz. As a first application, rotating fields are generated. The system can be enhanced in two stages to 16-phase operation with a bandwidth of 500 Hz and a 24 phase system with a bandwidth of up to 3 kHz.

  5. Density profile analysis during an ELM event in ASDEX Upgrade H-modes

    International Nuclear Information System (INIS)

    Nunes, I.; Manso, M.; Serra, F.; Horton, L.D.; Conway, G.D.; Loarte, A.

    2005-01-01

    This paper reports results on measurements of the density profiles. Here we analyse the behaviour of the electron density for a set of experiments in type I ELMy H-mode discharges in ASDEX Upgrade where the plasma current, plasma density, triangularity and input power were varied. Detailed measurements of the radial extent of the perturbation on the density profiles caused by the edge localized mode (ELM) crash (ELM affected depth), the velocity of the radial propagation of the perturbation as well as the width and gradient of the density pedestal are determined. The effect of a type I ELM event on the density profiles affects the outermost 20-40% of the plasma minor radius. At the scrape-off layer (SOL) the density profile broadens while in the pedestal region the density decreases resulting in a smaller density gradient. This change in the density profile defines a pivot point around which the density profile changes. The average radial velocity at the SOL is in the range 125-150 ms -1 and approximately constant for all the density layers far from the pivot point. The width of the density pedestal is approximately constant for all the ELMy H-mode discharges analysed, with values between 2 and 3.5 cm. These results are then compared with an analytical model where the width of the density is predominantly set by ionization (neutral penetration model). The width of the density profiles for L-mode discharges is included, since L- and H-mode have different particle transport. No agreement between the experimental results and the model is found

  6. Control of MHD instabilities by ECCD: ASDEX Upgrade results and implications for ITER

    International Nuclear Information System (INIS)

    Zohm, H.; Gantenbein, G.; Leuterer, F.; Manini, A.; Maraschek, M.; Yu, Q.

    2007-01-01

    The requirements for control of MHD instabilities by electron cyclotron current drive (ECCD) are reviewed. It is shown that a localized current drive is needed for control of both sawteeth and neoclassical tearing modes (NTMs). In the case of NTMs, the deposition width should be smaller than the island width for efficient control. At island widths smaller than the deposition width, as is predicted to occur in ITER, theory suggests that efficient control is possible only by modulating the ECCD power in phase with the island. These predictions are experimentally confirmed in ASDEX Upgrade for NTM control. Narrow deposition has also been used to extend the operational range of NTM stabilization in ASDEX Upgrade to lower q 95 and in the improved H-mode scenario. Our results suggest that, for the ITER ECCD system, good localization of the driven current profile as well as the capability to modulate the ECCD in phase with rotating modes will be needed for efficient MHD control by ECCD

  7. Thermal ions dilution and ITG suppression in ASDEX Upgrade ion ITBs

    International Nuclear Information System (INIS)

    Tardini, G.; Hobirk, J.; Igochine, V.G.; Maggi, C.F.; Martin, P.; McCune, D.; Peeters, A.G.; Sips, A.C.C.; Staebler, A.; Stober, J.

    2007-01-01

    Internal transport barriers (ITBs) in the ion channel in the tokamak ASDEX Upgrade allow for high energy confinement but collapse after only several energy confinement times. In this paper we show that in most cases the ITB phase is terminated clearly before the first ELM burst, thereby ruling out the ELMs as the main trigger of the ITB collapse. For the first time, the ITB formation and sustainment are found to be associated with a mechanism of transport suppression based on thermal ions dilution by the injected fast ions. Interestingly, such ITBs do not require reversed magnetic shear. The linear growth rate of the ion temperature gradient driven mode is computed as a function of the fast ion fraction with gyrokinetic stability analysis. Monte Carlo simulations predict the fast ion population to be above the gyrokinetic critical fraction in a region consistent with the experimental ITB width. The density threshold documented for the onset of ASDEX Upgrade ion ITBs is explained. The role of T i /T e and of the plasma sheared rotation for ITB sustainment are analysed. The stabilization mechanism presented here is consistent with the observed ITB lifetime of the order of the beam slowing down time. A possible runaway mechanism leading to ITB collapse is described. Finally, the relevance of this particular ITB scheme for ITER is discussed

  8. Development of laser induced breakdown spectroscopy for studying erosion, deposition, and fuel retention in ASDEX Upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Paris, Peeter; Piip, Kaarel [Institute of Physics, University of Tartu, Tartu (Estonia); Hakola, Antti [VTT Technical Research Centre of Finland, Espoo (Finland); Laan, Matti, E-mail: matti.laan@ut.ee [Institute of Physics, University of Tartu, Tartu (Estonia); Aints, Märt [Institute of Physics, University of Tartu, Tartu (Estonia); Koivuranta, Seppo; Likonen, Jari [VTT Technical Research Centre of Finland, Espoo (Finland); Lissovski, Aleksandr [Institute of Physics, University of Tartu, Tartu (Estonia); Mayer, Matej [Max-Planck-Institut für Plasmaphysik, Garching (Germany); Neu, Rudolf [Max-Planck-Institut für Plasmaphysik, Garching (Germany); Technische Universität München, Fachgebt Plasma-Material-Wechelwirkung, Garching (Germany); Rohde, Volker; Sugiyama, Kazuyoshi [Max-Planck-Institut für Plasmaphysik, Garching (Germany)

    2015-10-15

    Highlights: • LIBS development for in situ monitoring of first walls of fusion reactors. • Testing of samples extracted from the divertor tiles of ASDEX Upgrade. • Reliable detection of deuterium depth profiles. • A method of LIBS data processing which allows to find the elemental depth profiles. • Comparison of LIBS results with those of other surface characterization methods. - Abstract: The paper deals with the development of laser induced breakdown spectroscopy (LIBS) into an in situ method for studying erosion/deposition processes at the first walls of fusion reactors. To this end, samples extracted from the divertor tiles of ASDEX Upgrade after the 2009 plasma operations were analyzed using LIBS for their composition and the results were compared with other post mortem deposition data. Quantitative depth profiles for the elemental concentrations were extracted from LIBS spectra by applying a novel data processing method. In addition, both multiline and multispot averaging procedures were applied to reduce fluctuations in the data. The LIBS concentration profiles matched qualitatively with those given by secondary ion mass spectrometry and quantitatively with the ion-beam data. The deuterium content of the samples could be reliably determined if the surface densities were >10{sup 17} at/cm{sup 2}.

  9. Nonlinear evolution of the mode structure of ELMs in realistic ASDEX Upgrade geometry

    Energy Technology Data Exchange (ETDEWEB)

    Krebs, Isabel; Hoelzl, Matthias; Lackner, Karl; Guenter, Sibylle [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, Boltzmannstr. 2, Garching (Germany); Collaboration: The ASDEX Upgrade Team

    2013-07-01

    Edge-localized modes (ELMs) are edge instabilities in H-mode plasmas, which eject particles and energy. The suitability of the H-mode for future fusion reactors depends crucially on the exact ELM dynamics as they can damage plasma facing components if too large. We have simulated ELMs in ASDEX Upgrade geometry using the nonlinear MHD code JOREK. Emphasis was put on the mode structure evolution in the early ELM phase which is characterized by the exponential growth of the unstable toroidal Fourier harmonics followed by a phase of saturation. In the linear phase, toroidal harmonics grow independently, whereas at larger amplitudes, the nonlinear interaction between the toroidal harmonics influences their growth and structure. Prior to mode saturation, the evolution of the mode structure can be reproduced well by a simple quadratic mode-interaction model, which yields a possible explanation for the strong n=1 component of type-I ELMs observed in ASDEX Upgrade. In the linear phase of the simulations, intermediate toroidal mode numbers (n 6-14) are most unstable as predicted by the peeling-ballooning model. But non-linearly, the n=1 component becomes important due to an energy transfer from pairs of linearly dominant toroidal harmonics with neighboring mode numbers to the n=1. The latter thereby changes its spatial structure.

  10. Validation of neutral point on JT-60U, Alcator C-Mod and ASDEX-Upgrade tokamaks

    International Nuclear Information System (INIS)

    Nakamura, Yukiharu; Yoshino, Ryuji; Pautasso, Gabriella; Gruber, Otto; Jardin, Stephen

    2002-01-01

    Validation studies of a neutrally balanced vertical plasma position, so-called ''neutral point'', have been carried out by computational simulations and experiments under trilateral Japan-US-EU collaborations. It was clarified that the neutral point, where VDEs (Vertical Displacement Events) are hardly occurred, does exit in the Alcator C-Mod and ASDEX-Upgrade tokamaks as well as the JT-60U, consistent with the simulations. Meanwhile, precise details of the VDE behavior exhibit their own characters according to the individual of the tokamaks such as an up-down asymmetry of plasma shape. Sensitivity of the neutral point to the plasma shape and current profile was also addressed in detail. (author)

  11. Characterization and interpretation of the Edge Snake in between type-I edge localized modes at ASDEX Upgrade

    NARCIS (Netherlands)

    Sommer, F.; Günter, S.; Kallenbach, A.; Maraschek, M.; Boom, J.E.; Fischer, R.; Hicks, N.; Luhmann, N.C.; Park, H.K.; Reiter, B.; Wenninger, R.; Wolfrum, E.

    2011-01-01

    A new magnetohydrodynamic instability called the 'Edge Snake', which was found in 2006 at the tokamak ASDEX Upgrade during type-I ELMy H-modes, is investigated. It is located within the separatrix in the region of high temperature and density gradients and has a toroidal mode number of n = 1. The

  12. Fast-ion transport in the presence of magnetic reconnection induced by sawtooth oscillations in ASDEX Upgrade

    NARCIS (Netherlands)

    Geiger, B.; M. García-Muñoz,; Dux, R.; Ryter, F.; Tardini, G.; Orte, L. B.; Classen, I.G.J.; Fable, E.; Fischer, R.; Igochine, V.; McDermott, R. M.

    2014-01-01

    The transport of beam-generated fast ions has been investigated experimentally at the ASDEX Upgrade tokamak in the presence of sawtooth crashes. After sawtooth crashes, phase space resolved fast-ion D-alpha measurements show a significant reduction of the central fast-ion density-more than

  13. Phase-space resolved measurement of 2nd harmonic ion cyclotron heating using FIDA tomography at the ASDEX Upgrade tokamak

    DEFF Research Database (Denmark)

    Weiland, M.; Bilato, R.; Geiger, B.

    2017-01-01

    Recent upgrades to the FIDA (fast-ion D-alpha) diagnostic at ASDEX Upgrade allow to reconstruct the fast-ion phase space at several radial positions with decent energy and pitch resolution. These new diagnostic capabilities are applied to study the physics of 2nd harmonic ion cyclotron heating, w....... Furthermore, comparisons to other fast-ion diagnostics (neutron yield and neutral particle analyzers) are discussed....

  14. Energy transport to the divertor plates of ASDEX-Upgrade during ELMy H-mode phases

    International Nuclear Information System (INIS)

    Herrmann, A.; Laux, M.; Coster, D.; Neuhauser, J.; Reiter, D.; Schneider, R.; Weinlich, M.

    1995-01-01

    The energy flux to the ASDEX-Upgrade divertor plates is routinely measured by themography and Langmuir probes. The thermographically observed power decay length at the target plate is about 1 cm near the inboard separatrix. During an edge localized mode (ELM) of type I the density profiles are significantly, changed; an additional contribution occurs characterized by a power decay length in the order of 10 cm outside the separatrix and additional power is deposited into the private flux region. It is supposed that this is due to the changing, contribution of energy conduction versus convection. Results of ELM-modelling using the coupled B2-EIRENE code reproduce the main features of the experimental observations. The sheath transmission factor is calculated by combining themography and Langmuir probe data. ((orig.))

  15. Video tracking and post-mortem analysis of dust particles from all tungsten ASDEX Upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Endstrasser, N., E-mail: Nikolaus.Endstrasser@ipp.mpg.de [Max-Planck-Insitut fuer Plasmaphysik, EURATOM Association, Boltzmannstrasse 2, D-85748 Garching (Germany); Brochard, F. [Institut Jean Lamour, Nancy-Universite, Bvd. des Aiguillettes, F-54506 Vandoeuvre (France); Rohde, V., E-mail: Volker.Rohde@ipp.mpg.de [Max-Planck-Insitut fuer Plasmaphysik, EURATOM Association, Boltzmannstrasse 2, D-85748 Garching (Germany); Balden, M. [Max-Planck-Insitut fuer Plasmaphysik, EURATOM Association, Boltzmannstrasse 2, D-85748 Garching (Germany); Lunt, T.; Bardin, S.; Briancon, J.-L. [Institut Jean Lamour, Nancy-Universite, Bvd. des Aiguillettes, F-54506 Vandoeuvre (France); Neu, R. [Max-Planck-Insitut fuer Plasmaphysik, EURATOM Association, Boltzmannstrasse 2, D-85748 Garching (Germany)

    2011-08-01

    2D dust particle trajectories are extracted from fast framing camera videos of ASDEX Upgrade (AUG) by a new time- and resource-efficient code and classified into stationary hot spots, single-frame events and real dust particle fly-bys. Using hybrid global and local intensity thresholding and linear trajectory extrapolation individual particles could be tracked up to 80 ms. Even under challenging conditions such as high particle density and strong vacuum vessel illumination all particles detected for more than 50 frames are tracked correctly. During campaign 2009 dust has been trapped on five silicon wafer dust collectors strategically positioned within the vacuum vessel of the full tungsten AUG. Characterisation of the outer morphology and determination of the elemental composition of 5 x 10{sup 4} particles were performed via automated SEM-EDX analysis. A dust classification scheme based on these parameters was defined with the goal to link the particles to their most probable production sites.

  16. Fuzzy-neural approaches to the prediction of disruptions in ASDEX Upgrade

    International Nuclear Information System (INIS)

    Morabito, F.C.; Versaci, M.; Pautasso, G.; Tichmann, C.

    2001-01-01

    Disruption is a sudden loss of magnetic confinement that can cause damage to the machine walls and support structures. For this reason, it is of practical interest to be able to detect the onset of such an event early. A novel technique is presented of early prediction of plasma disruption in tokamak reactors which uses neural networks and 'fuzzy' inference. The studies carried out in the work make use of an experimental database of disruptive shots made available by the ASDEX Upgrade Team. The main result of the work is that, in the limit of the available database, it is possible to predict the onset of the disruptive event sufficiently in advance in order to put the control system into action. The proposed system is a modular scheme that exploits a decomposition of the original database carried out in a proper way. (author)

  17. Electromagnetic simulations of the ASDEX Upgrade ICRF Antenna with the TOPICA code

    International Nuclear Information System (INIS)

    Krivska, A.; Milanesio, D.; Bobkov, V.; Braun, F.; Noterdaeme, J.-M.

    2009-01-01

    Accurate and efficient simulation tools are necessary to optimize the ICRF antenna design for a set of operational conditions. The TOPICA code was developed for performance prediction and for the analysis of ICRF antenna systems in the presence of plasma, given realistic antenna geometries. Fully 3D antenna geometries can be adopted in TOPICA, just as in available commercial codes. But while those commercial codes cannot operate with a plasma loading, the TOPICA code correctly accounts for realistic plasma loading conditions, by means of the coupling with 1D FELICE code. This paper presents the evaluation of the electric current distribution on the structure, of the parallel electric field in the region between the straps and the plasma and the computation of sheaths driving RF potentials. Results of TOPICA simulations will help to optimize and re-design the ICRF ASDEX Upgrade antenna in order to reduce tungsten (W) sputtering attributed to the rectified sheath effect during ICRF operation.

  18. Shear strength of the ASDEX upgrade TF coil insulation: Rupture, fatigue and creep behaviour

    International Nuclear Information System (INIS)

    Streibl, B.; Maier, E.A.; Perchermeier, J.; Cimbrico, P.L.; Varni, G.; Pisani, D.; Deska, R.; Endreat, J.

    1987-03-01

    This report is concerned with the interlaminar shear strength of the insulation system for the 16 toroidal field (TF) coils of ASDEX upgrade. The interlaminar shear properties of the glass-epoxy insulation are primarily determined by the resin system (ARALDIT-F, HT 907, DZ 40) and its curing procedure. The pure resin was therefore tested first in tension. The results were taken into account for setting up the method of curing the TF coils. Shear tests of the complete glass-epopxy system were then conducted with tubular torque specimens providing a nearly homogeneous stress distribution. In particular, the influence of the amount of flexibilizer (5, 10, 15 parts of resin weight = PoW) on the rupture and fatigue strengths was assessed at a temperature T=60 C, as also was the temperature dependence of the creep rate (40 C, 60 C, 80 C). The results obtained are not based on safe statistics. Nevertheless, they show clear trends. (orig.)

  19. Erosion and migration of tungsten employed at the central column heat shield of ASDEX Upgrade

    International Nuclear Information System (INIS)

    Krieger, K.; Gong, X.; Balden, M.; Hildebrandt, D.; Maier, H.; Rohde, V.; Roth, J.; Schneider, W.

    2002-01-01

    In ASDEX Upgrade, tungsten was employed as plasma facing material at the central column heat shield in the plasma main chamber. The campaign averaged tungsten erosion flux was determined by measuring the difference of the W-layer thickness before and after the experimental campaign using ion beam analysis methods. The observed lateral variation and the total amount of eroded tungsten are attributed to erosion by impact of ions from the scrape-off layer plasma. Migration and redeposition of eroded tungsten were investigated by quantitative analysis of deposited tungsten on collector probes and wall samples. The obtained results, as well as the spectroscopically observed low tungsten plasma penetration probability, indicate that a major fraction of the eroded tungsten migrates predominantly through direct transport channels in the outer plasma scrape-off layer without entering the confined plasma

  20. Interpretation of low ionized impurity distributions in the ASDEX Upgrade divertor

    International Nuclear Information System (INIS)

    Lieder, G.; Napiontek, B.; Radtke, R.; Field, A.; Fussmann, G.; Kallenbach, A.; Kiemer, K.; Mayer, H.M.

    1993-01-01

    Design studies for reactor-like devices, like ITER, have particularly emphasized the importance of erosion and transport of material from the divertor target plates. In this context experimental measurements which can lead to a better understanding of the underlying physics are highly desirable. We discuss the spatial profiles of line emission from impurities measured in the divertor of ASDEX Upgrade with a recently developed multi-chord divertor spectrometer system. These profiles are obtained from observations in the ultra-violet/visible spectral range. The divertor spectrometer system was developed particularly to measure the erosion of the divertor plates and to study transport of the impurities and the ionization and recombination processes in the divertor region. (author) 6 refs., 3 figs., 2 tabs

  1. Interpretation of low ionized impurity distributions in the ASDEX Upgrade divertor

    Energy Technology Data Exchange (ETDEWEB)

    Lieder, G; Napiontek, B; Radtke, R; Field, A; Fussmann, G; Kallenbach, A; Kiemer, K; Mayer, H M [Max-Planck-Institut fuer Plasmaphysik, Garching (Germany)

    1994-12-31

    Design studies for reactor-like devices, like ITER, have particularly emphasized the importance of erosion and transport of material from the divertor target plates. In this context experimental measurements which can lead to a better understanding of the underlying physics are highly desirable. We discuss the spatial profiles of line emission from impurities measured in the divertor of ASDEX Upgrade with a recently developed multi-chord divertor spectrometer system. These profiles are obtained from observations in the ultra-violet/visible spectral range. The divertor spectrometer system was developed particularly to measure the erosion of the divertor plates and to study transport of the impurities and the ionization and recombination processes in the divertor region. (author) 6 refs., 3 figs., 2 tabs.

  2. Proposal of an alternative upper divertor in ASDEX Upgrade supported by EMC3-EIRENE simulations

    Directory of Open Access Journals (Sweden)

    T. Lunt

    2017-08-01

    Full Text Available We discuss the benefits of installing a pair of in-vessel coils with currents |Ifx| ≲ 50 kAt in the upper divertor of ASDEX Upgrade (AUG to study a series of ‘alternative’ divertor configurations, like the Snowflake (SF and the X-divertor (XD, that are currently considered as alternative solutions for the power exhaust problem. The possibility of operating the standard lower single-null (SN and double-null (DN would be preserved. Potential effects to reduce the peak parallel- and/or perpendicular heat flux are predicted from a simple geometrical-diffusive model as well as by numerical EMC3-EIRENE simulations for pure deuterium attached conditions with spatially constant diffusion coefficients. Beyond that a series of other potential transport- and radiation related heat flux mitigation effects are identified and could be studied experimentally with the modified upper divertor in the high-power divertor Tokamak AUG.

  3. Parameter dependences of the separatrix density in nitrogen seeded ASDEX Upgrade H-mode discharges

    Science.gov (United States)

    Kallenbach, A.; Sun, H. J.; Eich, T.; Carralero, D.; Hobirk, J.; Scarabosio, A.; Siccinio, M.; ASDEX Upgrade Team; EUROfusion MST1 Team

    2018-04-01

    The upstream separatrix electron density is an important interface parameter for core performance and divertor power exhaust. It has been measured in ASDEX Upgrade H-mode discharges by means of Thomson scattering using a self-consistent estimate of the upstream electron temperature under the assumption of Spitzer-Härm electron conduction. Its dependence on various plasma parameters has been tested for different plasma conditions in H-mode. The leading parameter determining n e,sep was found to be the neutral divertor pressure, which can be considered as an engineering parameter since it is determined mainly by the gas puff rate and the pumping speed. The experimentally found parameter dependence of n e,sep, which is dominated by the divertor neutral pressure, could be approximately reconciled by 2-point modelling.

  4. Measurement of turbulent electron temperature fluctuations on the ASDEX Upgrade tokamak using correlated electron cyclotron emission

    Energy Technology Data Exchange (ETDEWEB)

    Freethy, S. J., E-mail: simon.freethy@ipp.mpg.de [Max Planck Institute for Plasma Physics, 85748 Garching (Germany); Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Conway, G. D.; Happel, T.; Köhn, A. [Max Planck Institute for Plasma Physics, 85748 Garching (Germany); Classen, I.; Vanovac, B. [FOM Institute DIFFER, 5612 AJ Eindhoven (Netherlands); Creely, A. J.; White, A. E. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

    2016-11-15

    Turbulent temperature fluctuations are measured on the ASDEX Upgrade tokamak using pairs of closely spaced, narrow-band heterodyne radiometer channels and a standard correlation technique. The pre-detection spacing and bandwidth of the radiometer channel pairs is chosen such that they are physically separated less than a turbulent correlation length, but do not overlap. The radiometer has 4 fixed filter frequency channels and two tunable filter channels for added flexibility in the measurement position. Relative temperature fluctuation amplitudes are observed in a helium plasma to be δT/T = (0.76 ± 0.02)%, (0.67 ± 0.02)%, and (0.59 ± 0.03)% at normalised toroidal flux radius of ρ{sub tor} = 0.82, 0.75, and 0.68, respectively.

  5. Application for EURATOM priority support of additional heating for ASDEX Upgrade, phase I and phase II

    International Nuclear Information System (INIS)

    Koeppendoerfer, W.; Blaumoser, M.; Ennen, K.; Gruber, J.; Gruber, O.; Jandl, O.; Kaufmann, M.; Kollotzek, H.; Kotzlowski, H.; Lackner, E.; Lackner, K.; Larcher, T. von; Neuhauser, J.; Pillsticker, M.; Poehlchen, R.; Preis, H.; Schneider, H.; Seidel, U.; Sombach, B.; Streibl, B.; Werner, F.; Wieczorek, A.; Speth, E.; Pennigsfeld, F.P.; Feist, J.H.; Freudenberger, K.; Kolos, J.; Kunze, R.C.; Lohnert, H.; Melkus, W.; Ott, W.; Riedler, H.; Staebler, A.; Vollmer, O.; Wittenbecher, K.; Wulff, G.; Noterdaeme, J.M.; Wesner, F.; Baeumler, J.; Braun, F.; Fritsch, R.; Hofmeister, F.; Mark, E. von; Puri, S.; Soell, M.; Steinmetz, K.; Wedler, H.

    1985-04-01

    In order to reach the full performance plasma parameters of ASDEX Upgrade as provided by the machine technique a heating power of 12 to 15 MW is required. For the minimum required power the appropriate choice for the basic heating system are 6 MW ICRH and 6 MW neutral injection, both with a long pulse capability of up to 10 seconds. ICRH in a frequency range of 30 to 120 MHz shall cover He 3 minority, hydrogen fundamental and 2nd harmonic and deuterium 2nd harmonic heating. For neutral injection four JET sources with 60 keV H 0 and 80 A combined in one injection box were chosen. The averaged injection angle is 24 0 to perpendicular at Rsub(O) = 1.7 m. Both systems shall be installed during 1988. The costs are 57.4 MDM for both. (orig./GG)

  6. Test of the predictive capability of B2-Eirene on ASDEX-Upgrade

    International Nuclear Information System (INIS)

    Schneider, R.; Coster, D.P.; Kallenbach, A.

    2001-01-01

    Based on validated B2-Eirene results for the previous divertor of ASDEX Upgrade, the modelling predictions for the new divertor are compared with the actual experimental results. For the same experimental scenarios (L-mode) in both divertors the predictions are robust and in agreement with experimental results. For a full quantitative agreement in H-mode both the carbon chemical sputtering yield and the radial transport had to be adjusted. The new divertor has a reduced power load due to larger radiation losses. These are caused by larger hydrogen losses, enhancement of carbon radiation due to radial transport and convective energy transport into the radiation zone, and larger radial energy transport in the divertor. (author)

  7. Edge transport and its interconnection with main chamber recycling in ASDEX upgrade

    International Nuclear Information System (INIS)

    Kallenbach, A.; Dux, R.; Gafert, J.

    2003-01-01

    Edge profiles of electron temperature and density are measured in ASDEX Upgrade with high spatial resolution of 2-3 mm with Thomson scattering. In the region of the edge transport barrier in ELMy H-mode, the gradient lengths of T e and n e are found closely coupled, with the temperature profile twice as steep as the density profile corresponding to η e ∼ 2. The edge density in the region of the barrier foot is closely coupled to the main chamber recycling, with no strong dependence on other parameters. In contrast the density rise from the outer barrier foot to the pedestal exhibits pronounced dependence on plasma current and shaping, indicating quite different mechanisms determining the absolute density and its gradient. (author)

  8. Chapter 7: High-Density H-Mode Operation in ASDEX Upgrade

    International Nuclear Information System (INIS)

    Stober, Joerg Karl; Lang, Peter Thomas; Mertens, Vitus

    2003-01-01

    Recent results are reported on the maximum achievable H-mode density and the behavior of pedestal density and central density peaking as this limit is approached. The maximum achievable H-mode density roughly scales as the Greenwald density, though a dependence on B t is clearly observed. In contrast to the stiff temperature profiles, the density profiles seem to allow more shape variation and especially with high-field-side pellet-injection, strongly peaked profiles with good confinement have been achieved. Also, spontaneous density peaking at high densities is observed in ASDEX Upgrade, which is related to the generally observed large time constants for the density profile equilibration. The equilibrated density profile shapes depend strongly on the heat-flux profile in the sense that central heating leads to significantly flatter profiles

  9. Further insight into the mechanism of hydrocarbon layer formation below the divertor of ASDEX Upgrade

    International Nuclear Information System (INIS)

    Mayer, M; Rohde, V

    2006-01-01

    The surface loss probability of hydrocarbon radicals was measured below the roof baffle of the ASDEX Upgrade divertor using the cavity technique. Hydrocarbon layers are mainly formed by sticking of hydrocarbon radicals with high surface loss probabilities of about 0.2 and close to unity. In addition to sticking, re-erosion by atomic hydrogen plays an important role in layer formation. The temperature dependence of layer formation was measured with heated and cooled long term samples from 77 to 475 K. The layer growth rate is larger by a factor of about 40 at 77 K compared with room temperature, while it is lower by a factor of about 70 at 475 K than at room temperature due to enhanced re-erosion. Implications of the results for predictions of tritium retention in future fusion devices and hydrocarbon layer formation on mirror surfaces are discussed

  10. Poloidal asymmetries of the heavy ions in the ASDEX Upgrade tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Odstrcil, Tomas [Max-Planck-Institut fuer Plasmaphysik, Garching (Germany); Physik-Department E28, Technische Universitaet Muenchen, Garching (Germany); Puetterich, Thomas; Angioni, Clemente; Bilato, Roberto; Gude, Anja; Vezinet, Didier [Max-Planck-Institut fuer Plasmaphysik, Garching (Germany); Mazon, Didier [CEA, IRFM, Saint Paul-lez-Durance (France); Collaboration: ASDEX Upgrade Team

    2015-05-01

    Poloidal asymmetries of heavy ions in the tokamak plasma are caused by the presence of forces parallel with field-lines which have comparable magnitude to the thermal pressure. The most important examples are the centrifugal force (CF) and the electric force (EF). The CF is caused by fast toroidal rotation of the plasma column which is pushing impurity ions, that have a substantially higher mass than the main ions, on the outer-side of the plasma. And the EF can be produced by ion cyclotron heated fast particles with high pitch angle that are trapped by the mirror force on the low field side of the plasma. The excessive charge produced by these particles is affecting highly charged impurities and pushing them to the high field side of the plasma. From predictions based on neoclassical and turbulent theory, it follows that the radial flux of heavy ions will be significantly changed by the presence of these asymmetries. The purpose of this study is to investigate the presence of these asymmetries in ASDEX Upgrade and verify the predicted consequences on the particles flux. High intrinsic content of the tungsten in AUG plasma makes this device well suitable for such studies. Precise measurement of the SXR (soft-X-ray) radiation profiles has identified a presence of CF generated asymmetries in every NBI heated Asdex discharge. Poloidal asymmetry should than lead to the significant change in the neoclassical and turbulent radial transport of these heavy ions. High intrinsic content of the tungsten in Asdex plasma makes this device well suitable for studying these asymmetries. Precise measurement of the SXR (soft-X-ray) radiation profiles has identified a presence of CF generated asymmetries in every NBI heated Asdex discharge. For heavy and highly charged impurities multiple mechanisms exist that produce non-constant impurities densities on the flux surfaces. As for neoclassical and turbulent transport models such an asymmetry is of highly importance an effort is

  11. Feedback controlled, reactor relevant, high-density, high-confinement scenarios at ASDEX Upgrade

    Science.gov (United States)

    Lang, P. T.; Blanken, T. C.; Dunne, M.; McDermott, R. M.; Wolfrum, E.; Bobkov, V.; Felici, F.; Fischer, R.; Janky, F.; Kallenbach, A.; Kardaun, O.; Kudlacek, O.; Mertens, V.; Mlynek, A.; Ploeckl, B.; Stober, J. K.; Treutterer, W.; Zohm, H.; ASDEX Upgrade Team

    2018-03-01

    One main programme topic at the ASDEX Upgrade all-metal-wall tokamak is development of a high-density regime with central densities at reactor grade level while retaining high-confinement properties. This required development of appropriate control techniques capable of coping with the pellet tool, a powerful means of fuelling but one which presented challenges to the control system for handling of related perturbations. Real-time density profile control was demonstrated, raising the core density well above the Greenwald density while retaining the edge density in order to avoid confinement losses. Recently, a new model-based approach was implemented that allows direct control of the central density. Investigations focussed first on the N-seeding scenario owing to its proven potential to yield confinement enhancements. Combining pellets and N seeding was found to improve the divertor buffering further and enhance the operational range accessible. For core densities up to about the Greenwald density, a clear improvement with respect to the non-seeding reference was achieved; however, at higher densities this benefit is reduced. This behaviour is attributed to recurrence of an outward shift of the edge density profile, resulting in a reduced peeling-ballooning stability. This is similar to the shift seen during strong gas puffing, which is required to prevent impurity influx in ASDEX Upgrade. First tests indicate that highly-shaped plasma configurations like the ITER base-line scenario, respond very well to pellet injection, showing efficient fuelling with no measurable impact on the edge density profile.

  12. Advances in the density profile evaluation from broadband reflectometry on ASDEX upgrade

    International Nuclear Information System (INIS)

    Varela, P.; Manso, M.; Conway, G.

    2001-01-01

    The high temporal and spatial resolutions provided by broadband microwave reflectometry make it an attractive diagnostic technique to measure the density profile in fusion plasmas. However, great problems have been encountered due to the plasma turbulence that difficult, and sometimes prevent, the routine evaluation of density profiles. Advanced broadband systems employ ultra-fast sweeping in an attempt to perform the profile measurement in a time window smaller than the temporal scale of the main plasma fluctuations but this is not sufficient. Indeed, abrupt plasma movements and/or spatial turbulence always affect the reflectometry signals, as shown by numerical studies (with both one- and two-dimensional codes), for the case of ultra-fast sweeping and pulse radar systems. For this reason not only the system performance is important but the software tools also play a crucial role for reflectometry to become a standard density profile diagnostic. Here we present the recent advances towards automatic evaluation of density profiles from broadband reflectometry on ASDEX Upgrade. For regimes with moderate levels of plasma turbulence, density profiles are obtained from single reflectometry samples (temporal resolution of 20 μs), and for higher turbulence levels average profiles are obtained from bursts of ultra-fast (20 μs), closely spaced (10 μs) sweeps. This method improved the accuracy and reliability of density profiles, which can now be obtained automatically from the edge to the bulk plasma - using reflectometry alone - in most plasma regimes of ASDEX Upgrade. New data processing capability has been implemented that allows the profiles to be available to the end-users 10-12 minutes after each discharge. These developments were possible due to the flexibility and high performance of the control and data acquisition systems and to the large number of measurements that can be performed with the diagnostic during each discharge (720 profiles both on the low- and

  13. The MHD stability analysis of type I ELMS in ASDEX Upgrade Tokamak

    International Nuclear Information System (INIS)

    Saarelma, S.

    2000-01-01

    The ELMs or edge localized modes are plasma instabilities localized in the edge region of a tokamak plasma. They cause periodic expulsions of particles and energy. The ELMs play a significant role in the confinement of the plasma, helium exhaust and diverter erosion. These are crucial issues in tokamak operation and, thus, understanding the underlying physical mechanism behind the ELM phenomenon is very important. The ELMs are classified into three different types based on the plasma conditions, where they are observed, and, on the ELM frequency response to the heating power. In this thesis, type I ELMs which are the most intense and the most damaging to the diverters, are studied. A model for the ELMs presented by Connor et al. is tested in experimental ASDEX Upgrade plasmas. In the Connor model, the ELMs are explained as a result of two instabilities, ballooning and peeling modes. Also a phenomenon called the bootstrap current plays a significant role by being the destabilising trigger to the peeling modes. The method used to study the model is MHD or magnetohydrodynamics. The theory of the ideal MHD equilibrium and the linear stability analysis is described. Inclusion of the bootstrap current to the equilibrium construction is introduced. The equilibria are created using experimental data from plasma shots that display type I ELMs. The stability analysis indicates that the investigated ELM model is a feasible explanation for type I ELMs. The pressure gradient near the plasma edge was found to be close to the ballooning stability boundary as predicted by the model. The peeling mode stability analysis confirms the prediction of the model that as the bootstrap current increases, the plasma becomes unstable for peeling modes with low to intermediate toroidal mode numbers. The mode numbers agree with the experimental results. In the experiments with high triangularity, low ELM frequency and ELM-free periods were observed. This indicates better stability of the plasma

  14. Characterization and interpretation of the Edge Snake in between type-I edge localized modes at ASDEX Upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Sommer, F; Guenter, S; Kallenbach, A; Maraschek, M; Boom, J; Fischer, R; Hicks, N; Reiter, B; Wolfrum, E [Max-Planck-Institut fuer Plasmaphysik, Boltzmannstrasse 2, D-85748 Garching, EURATOM Association (Germany); Luhmann, N C Jr [University of California at Davis, Davis, CA 95616 (United States); Park, H K [POSTECH, Pahang, Gyeongbuk 790-784 (Korea, Republic of); Wenninger, R, E-mail: fabian.sommer@ipp.mpg.de [Universitaetssternwarte der Ludwig-Maximilians-Universitaet, D-81679 Muenchen (Germany)

    2011-08-15

    A new magnetohydrodynamic instability called the 'Edge Snake', which was found in 2006 at the tokamak ASDEX Upgrade during type-I ELMy H-modes, is investigated. It is located within the separatrix in the region of high temperature and density gradients and has a toroidal mode number of n = 1. The Edge Snake consists of a radially and poloidally strongly localized current wire, in which the temperature and density profiles flatten. This significant reduction in pressure gradient leads to a reduction in the neoclassical Bootstrap current and can plausibly explain the drive of the instability. The experimental observations point towards a magnetic island with a defect current inside the O-point of the island. The Edge Snake is compared with similar instabilities at JET, DIII-D and ASDEX Upgrade.

  15. Experimental studies and modelling of high radiation and high density plasmas in the ASDEX upgrade tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Casali, Livia

    2015-11-24

    Fusion plasmas contain impurities, either intrinsic originating from the wall, or injected willfully with the aim of reducing power loads on machine components by converting heat flux into radiation. The understanding and the prediction of the effects of these impurities and their radiation on plasma performances is crucial in order to retain good confinement. In addition, it is important to understand the impact of pellet injection on plasma performance since this technique allows higher core densities which are required to maximise the fusion power. This thesis contributes to these efforts through both experimental investigations and modelling. Experiments were conducted at ASDEX Upgrade which has a full-W wall. Impurity seeding was applied to H-modes by injecting nitrogen and also medium-Z impurities such as Kr and Ar to assess the impact of both edge and central radiation on confinement. A database of about 25 discharges has been collected and analysed. A wide range of plasma parameters was achieved up to ITER relevant values such as high Greenwald and high radiation fractions. Transport analyses taking into account the radiation distribution reveal that edge localised radiation losses do not significantly impact confinement as long as the H-mode pedestal is sustained. N seeding induces higher pedestal pressure which is propagated to the core via profile stiffness. Central radiation must be limited and controlled to avoid confinement degradation. This requires reliable control of the impurity concentration but also possibilities to act on the ELM frequency which must be kept high enough to avoid an irreversible impurity accumulation in the centre and the consequent radiation collapse. The key role of the f{sub ELM} is confirmed also by the analysis of N+He discharges. Non-coronal effects affect the radiation of low-Z impurities at the plasma edge. Due to the radial transport, the steep temperature gradients and the ELM flush out, a local equilibrium cannot be

  16. Main-ion temperature and plasma rotation measurements based on scattering of electron cyclotron heating waves in ASDEX Upgrade

    DEFF Research Database (Denmark)

    Pedersen, Morten Stejner; Rasmussen, Jesper; Nielsen, Stefan Kragh

    2017-01-01

    We demonstrate measurements of spectra of O-mode electron cyclotron resonance heating (ECRH) waves scattered collectively from microscopic plasma fluctuations in ASDEX Upgrade discharges with an ITER-like ECRH scenario. The measured spectra are shown to allow determination of the main ion...... temperature and plasma rotation velocity. This demonstrates that ECRH systems can be exploited for diagnostic purposes alongside their primary heating purpose in a reactor relevant scenario....

  17. Characterization of ion heat conduction in JET and ASDEX Upgrade plasmas with and without internal transport barriers

    Energy Technology Data Exchange (ETDEWEB)

    Wolf, R C [Institut fuer Plasmaphysik, Forschungszentrum Juelich, Association EURATOM/FZJ, Trilateral Euregio Cluster, D-52425 Juelich (Germany); Baranov, Y [UKAEA/EURATOM Fusion Association, Culham Science Centre, Abingdon, OX14 3DB (United Kingdom); Garbet, X [Association EURATOM-CEA sur la fusion, CEA Cadarache, F-13108 St Paul lez Durance (France); Hawkes, N [UKAEA/EURATOM Fusion Association, Culham Science Centre, Abingdon, OX14 3DB (United Kingdom); Peeters, A G [Max-Planck-Institut fuer Plasmaphysik, EURATOM-Assoziation, D-85748 Garching (Germany); Challis, C [UKAEA/EURATOM Fusion Association, Culham Science Centre, Abingdon, OX14 3DB (United Kingdom); Baar, M de [FOM Instituut voor Plasmafyisica Rijnhuizen, Association EURATO-FOM, Trilateral Euregio Cluster, PO Box 1207, 3430 BE Nieuwegein (Netherlands); Giroud, C [FOM Instituut voor Plasmafyisica Rijnhuizen, Association EURATO-FOM, Trilateral Euregio Cluster, PO Box 1207, 3430 BE Nieuwegein (Netherlands); Joffrin, E [Association EURATOM-CEA sur la fusion, CEA Cadarache, F-13108 St Paul lez Durance (France); Mantsinen, M [Helsinki University of Technology, Association-EURATOM Tekes, FIN-02015 HUT (Finland); Mazon, D [Association EURATOM-CEA sur la fusion, CEA Cadarache, F-13108 St Paul lez Durance (France); Meister, H [Max-Planck-Institut fuer Plasmaphysik, EURATOM-Assoziation, D-85748 Garching (Germany); Suttrop, W [Max-Planck-Institut fuer Plasmaphysik, EURATOM-Assoziation, D-85748 Garching (Germany); Zastrow, K-D [UKAEA/EURATOM Fusion Association, Culham Science Centre, Abingdon, OX14 3DB (United Kingdom)

    2003-09-01

    In ASDEX Upgrade and JET, the ion temperature profiles can be described by R/L{sub Ti} which exhibits only little variations, both locally, when comparing different discharges, and radially over a wide range of the poloidal cross-section. Considering a change of the local ion heat flux of more than a factor of two, this behaviour indicates some degree of profile stiffness. In JET, covering a large ion temperature range from 1 to 25 keV, the normalized ion temperature gradient, R/L{sub Ti}, shows a dependence on the electron to ion temperature ratio or toroidal rotational shear. In particular, in hot ion plasmas, produced predominantly by neutral beam heating at low densities, in which large T{sub i}/T{sub e} is coupled to strong toroidal rotation, the effect of the two quantities cannot be distinguished. Both in ASDEX Upgrade and JET, plasmas with internal transport barriers (ITBs), including the PEP mode in JET, are characterized by a significant increase of R/L{sub Ti} above the value of L- and H-mode plasmas. In agreement with previous ASDEX Upgrade results, no increase of the ion heat transport in reversed magnetic shear ITB plasmas is found in JET when raising the electron heating. Evidence is presented that magnetic shear directly influences R/L{sub Ti}, namely decreasing the ion heat transport when going from weakly positive to negative magnetic shear.

  18. Influence of plasma rotation on tearing mode stability on the ASDEX upgrade tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Fietz, Sina Marie Ariane

    2013-12-16

    Neoclassical tearing modes (NTM) are one of the most serious performance limiting instabilities in next-step fusion devices like ITER. NTMs are destabilised as a consequence of a seed perturbation (trigger) and are driven by a loss of helical bootstrap current inside the island. The appearance of these instabilities is accompanied with a loss of confined plasma energy. Additionally, these modes can stop the plasma rotation, lock to the vessel wall, flush out all plasma energy and terminate a discharge via a disruption. In ITER the confinement reduction will limit the achievable fusion power, whereas a disruption is likely to damage the vessel wall. In order to mitigate and control NTMs in ITER, extrapolations based on the present understanding and observations must be made. One key issue is the rotation dependence of NTMs, especially at the NTM onset. ITER will be operated at low plasma rotation, which is different from most present day experiments. No theory is currently available to describe this dependence. Experiments are therefore required to provide a basis for the theory to describe the physics. Additionally from the experiments scalings can be developed and extrapolated in order to predict the NTM behaviour in the parameter range relevant for ITER. Another important issue is the influence of externally applied magnetic perturbation (MP) fields on the NTM stability and frequency. These fields will be used in ITER primarily for the mitigation of edge instabilities. As a side effect they can slow down an NTM and the plasma rotation, which supports the appearance of locked modes. Additionally, they can also influence the stability of an NTM. This interaction has to be predicted for ITER, based on models validated at present day devices. In this work the influence of plasma rotation on the NTM onset at the ASDEX Upgrade tokamak (AUG) is investigated. An onset database has been created in which the different trigger mechanisms have been identified. Based on this

  19. Influence of plasma rotation on tearing mode stability on the ASDEX upgrade tokamak

    International Nuclear Information System (INIS)

    Fietz, Sina Marie Ariane

    2013-01-01

    Neoclassical tearing modes (NTM) are one of the most serious performance limiting instabilities in next-step fusion devices like ITER. NTMs are destabilised as a consequence of a seed perturbation (trigger) and are driven by a loss of helical bootstrap current inside the island. The appearance of these instabilities is accompanied with a loss of confined plasma energy. Additionally, these modes can stop the plasma rotation, lock to the vessel wall, flush out all plasma energy and terminate a discharge via a disruption. In ITER the confinement reduction will limit the achievable fusion power, whereas a disruption is likely to damage the vessel wall. In order to mitigate and control NTMs in ITER, extrapolations based on the present understanding and observations must be made. One key issue is the rotation dependence of NTMs, especially at the NTM onset. ITER will be operated at low plasma rotation, which is different from most present day experiments. No theory is currently available to describe this dependence. Experiments are therefore required to provide a basis for the theory to describe the physics. Additionally from the experiments scalings can be developed and extrapolated in order to predict the NTM behaviour in the parameter range relevant for ITER. Another important issue is the influence of externally applied magnetic perturbation (MP) fields on the NTM stability and frequency. These fields will be used in ITER primarily for the mitigation of edge instabilities. As a side effect they can slow down an NTM and the plasma rotation, which supports the appearance of locked modes. Additionally, they can also influence the stability of an NTM. This interaction has to be predicted for ITER, based on models validated at present day devices. In this work the influence of plasma rotation on the NTM onset at the ASDEX Upgrade tokamak (AUG) is investigated. An onset database has been created in which the different trigger mechanisms have been identified. Based on this

  20. Comparison of wall/divertor deuterium retention and plasma fueling requirements on the DIII-D, TdeV, and ASDEX-upgrade tokamaks

    Energy Technology Data Exchange (ETDEWEB)

    Maingi, R. [Oak Ridge Associated Universities, TN (United States); Terreault, B. [Inst. National de la Recherche Scientifique, Varennes, Quebec (Canada); Haas, G. [Max Planck Inst. fuer Plasmaphysik, Garching (Germany)] [and others

    1996-06-01

    The authors present a comparison of the wall deuterium retention and plasma fueling requirements of three diverted tokamaks, DIII-D, TdeV, and ASDEX-Upgrade, with different fractions of graphite coverage of stainless steel or Inconel outer walls and different heating modes. Data from particle balance experiments on each tokamak demonstrate well-defined differences in wall retention of deuterium gas, even though all three tokamaks have complete graphite coverage of divertor components and all three are routinely boronized. This paper compares the evolution of the change in wall loading and net fueling efficiency for gas during dedicated experiments without Helium Glow Discharge Cleaning on the DIII-D and TdeV tokamaks. On the DIII-D tokamak, it was demonstrated that the wall loading could be increased by > 1,250 Torr-1 (equivalent to 150 {times} plasma particle content) plasma inventories resulting in an increase in fueling efficiency from 0.08 to 0.25, whereas the wall loading on the TdeV tokamak could only be increased by < 35 Torr-{ell} (equivalent to 50{times} plasma particle content) plasma inventories at a maximum fueling efficiency {approximately} 1. Data from the ASDEX-Upgrade tokamak suggests qualitative behavior of wall retention and fueling efficiency similar to DIII-D.

  1. Electromagnetic and structural global model of the TF magnet system in ASDEX Upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Zammuto, I., E-mail: irene.zammuto@ipp.mpg.de [Max-Planck-Institut für Plasmaphysik, EURATOM Association, D-85740 Garching (Germany); Streibl, B.; Giannone, L.; Herrmann, A.; Kallenbach, A.; Mertens, V. [Max-Planck-Institut für Plasmaphysik, EURATOM Association, D-85740 Garching (Germany)

    2013-10-15

    Highlights: ► An electromagnetic and structural FE 3D model is set up for ASDEX Upgrade. ► The model is benchmarked against the old design results, present displacement measurements. ► The benchmarked model is applied to the present plasma configurations, which have a different poloidal field distribution with respect to the design case. ► The different poloidal field influences the out-of-plane force distribution, thus requiring an update of the TF safety system. -- Abstract: The enhancements carried out in the tokamak ASDEX Upgrade (AUG) are oriented toward the preparation of the future physics-related activities of ITER and DEMO. To address the main ITER issues, plasma configurations with a wider operational limit (e.g. higher triangularity) are planned for the future experimental campaigns in AUG. To evaluate the mechanical impact on the toroidal field (TF) magnet system a combined electromagnetic and structural finite element model was set up. At first extensive benchmarks of the models are carried out against the AUG reference design configurations with respect to stress [1–3], lateral displacement measurements and poloidal flux pattern. The numerical model was then applied to a set of actual high triangularity (HT) configurations generated by a more favorable poloidal field (PF) current distribution made possible by an extension of the power supply system. The resulting change of the poloidal flux pattern and the lateral force distribution has consequences for the coil shear stress and vault stability. Both aspects are monitored by a safety system measuring the PF flux placed on top and bottom of the outer surface of two TF coils (TFCs) between vault and the TFC supporting structure, so called Turn Over Structure (TOS). The range of the new HT configurations has induced a modification of the flux pattern, so that an adaptation of safety system is required to protect the TFCs system. Following the same criteria of the old safety system [4,5], a new

  2. Deployment and future prospects of high performance diagnostics featuring serial I/O (SIO) data acquisition (DAQ) at ASDEX Upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Behler, K., E-mail: karl.behler@ipp.mpg.de [Max-Planck-Institut fuer Plasmaphysik, Boltzmannstr. 2, D-85748 Garching bei Muenchen (Germany); Blank, H.; Eixenberger, H. [Max-Planck-Institut fuer Plasmaphysik, Boltzmannstr. 2, D-85748 Garching bei Muenchen (Germany); Fitzek, M. [Unlimited Computer Systems GmbH, Seeshaupterstr. 15, D-82393 Iffeldorf (Germany); Lohs, A. [Max-Planck-Institut fuer Plasmaphysik, Boltzmannstr. 2, D-85748 Garching bei Muenchen (Germany); Lueddecke, K. [Unlimited Computer Systems GmbH, Seeshaupterstr. 15, D-82393 Iffeldorf (Germany); Merkel, R. [Max-Planck-Institut fuer Plasmaphysik, Boltzmannstr. 2, D-85748 Garching bei Muenchen (Germany)

    2012-12-15

    Highlights: Black-Right-Pointing-Pointer The high sustained data rates transferring measured data from periphery into memory of computers. Black-Right-Pointing-Pointer The achieved low latency in real-time interrupt handling under Solaris 10. Black-Right-Pointing-Pointer The new prototype of an even more powerful 2nd generation SIO II device. Black-Right-Pointing-Pointer The fusion of all blocks of board logic (serializer, FIFO, TDC, merge engine, PCIe controller) into one single FPGA simplifying the boards physical layout significantly. - Abstract: The SIO DAQ concept used at the ASDEX Upgrade fusion experiment features data acquisition from a modular front-end (a modular crate-and-interface-cards concept for analog and digital input and output) over standardized serial lines and via a serial input/output computer interface card (the SIO card) in real-time directly into the main memory of a host computer. Deployment of a series of diagnostics using SIO led to various solutions and configurations for the different requirements. Experience has been gained and lessons learned applying the SIO concept at its technical limits. Requirements for a further development of the SIO concept have been identified, and a performance improvement by a factor of 4-8 beyond its current limits seems achievable. An effort has been started to develop a SIO version 2 (SIO II) featuring upgraded serial links and a more powerful FPGA for merging and forwarding data streams to host computer memory. (Compatibility with the existing SIO (SIO I) front-end system has to be maintained.) This paper presents results achieved and experiences gained in the deployment of SIO I, the status of SIO II development (currently in the prototype phase), and projected enhancements and updates to existing implementations.

  3. Profile measurements of the electron temperature on the ASDEX Upgrade, COMPASS, and ISTTOK tokamak using Thomson scattering, triple, and ball-pen probes

    Science.gov (United States)

    Adamek, J.; Müller, H. W.; Silva, C.; Schrittwieser, R.; Ionita, C.; Mehlmann, F.; Costea, S.; Horacek, J.; Kurzan, B.; Bilkova, P.; Böhm, P.; Aftanas, M.; Vondracek, P.; Stöckel, J.; Panek, R.; Fernandes, H.; Figueiredo, H.

    2016-04-01

    The ball-pen probe (BPP) technique is used successfully to make profile measurements of the electron temperature on the ASDEX Upgrade (Axially Symmetric Divertor Experiment), COMPASS (COMPact ASSembly), and ISTTOK (Instituto Superior Tecnico TOKamak) tokamak. The electron temperature is provided by a combination of the BPP potential (ΦBPP) and the floating potential (Vfl) of the Langmuir probe (LP), which is compared with the Thomson scattering diagnostic on ASDEX Upgrade and COMPASS. Excellent agreement between the two diagnostics is obtained for circular and diverted plasmas and different heating mechanisms (Ohmic, NBI, ECRH) in deuterium discharges with the same formula Te = (ΦBPP - Vfl)/2.2. The comparative measurements of the electron temperature using BPP/LP and triple probe (TP) techniques on the ISTTOK tokamak show good agreement of averaged values only inside the separatrix. It was also found that the TP provides the electron temperature with significantly higher standard deviation than BPP/LP. However, the resulting values of both techniques are well in the phase with the maximum of cross-correlation function being 0.8.

  4. Profile measurements of the electron temperature on the ASDEX Upgrade, COMPASS, and ISTTOK tokamak using Thomson scattering, triple, and ball-pen probes

    Energy Technology Data Exchange (ETDEWEB)

    Adamek, J., E-mail: adamek@ipp.cas.cz; Horacek, J.; Bilkova, P.; Böhm, P.; Aftanas, M.; Vondracek, P.; Stöckel, J.; Panek, R. [Institute of Plasma Physics, Prague (Czech Republic); Müller, H. W. [Max-Planck-Institute for Plasma Physics, Garching near Munich (Germany); Institute of Materials Chemistry & Research, University of Vienna, Vienna (Austria); Silva, C.; Fernandes, H.; Figueiredo, H. [Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa (Portugal); Schrittwieser, R.; Ionita, C.; Mehlmann, F.; Costea, S. [Institute for Ion Physics and Applied Physics, University of Innsbruck, Innsbruck (Austria); Kurzan, B. [Max-Planck-Institute for Plasma Physics, Garching near Munich (Germany)

    2016-04-15

    The ball-pen probe (BPP) technique is used successfully to make profile measurements of the electron temperature on the ASDEX Upgrade (Axially Symmetric Divertor Experiment), COMPASS (COMPact ASSembly), and ISTTOK (Instituto Superior Tecnico TOKamak) tokamak. The electron temperature is provided by a combination of the BPP potential (Φ{sub BPP}) and the floating potential (V{sub fl}) of the Langmuir probe (LP), which is compared with the Thomson scattering diagnostic on ASDEX Upgrade and COMPASS. Excellent agreement between the two diagnostics is obtained for circular and diverted plasmas and different heating mechanisms (Ohmic, NBI, ECRH) in deuterium discharges with the same formula T{sub e} = (Φ{sub BPP} − V{sub fl})/2.2. The comparative measurements of the electron temperature using BPP/LP and triple probe (TP) techniques on the ISTTOK tokamak show good agreement of averaged values only inside the separatrix. It was also found that the TP provides the electron temperature with significantly higher standard deviation than BPP/LP. However, the resulting values of both techniques are well in the phase with the maximum of cross-correlation function being 0.8.

  5. Profile measurements of the electron temperature on the ASDEX Upgrade, COMPASS, and ISTTOK tokamak using Thomson scattering, triple, and ball-pen probes

    International Nuclear Information System (INIS)

    Adamek, J.; Horacek, J.; Bilkova, P.; Böhm, P.; Aftanas, M.; Vondracek, P.; Stöckel, J.; Panek, R.; Müller, H. W.; Silva, C.; Fernandes, H.; Figueiredo, H.; Schrittwieser, R.; Ionita, C.; Mehlmann, F.; Costea, S.; Kurzan, B.

    2016-01-01

    The ball-pen probe (BPP) technique is used successfully to make profile measurements of the electron temperature on the ASDEX Upgrade (Axially Symmetric Divertor Experiment), COMPASS (COMPact ASSembly), and ISTTOK (Instituto Superior Tecnico TOKamak) tokamak. The electron temperature is provided by a combination of the BPP potential (Φ_B_P_P) and the floating potential (V_f_l) of the Langmuir probe (LP), which is compared with the Thomson scattering diagnostic on ASDEX Upgrade and COMPASS. Excellent agreement between the two diagnostics is obtained for circular and diverted plasmas and different heating mechanisms (Ohmic, NBI, ECRH) in deuterium discharges with the same formula T_e = (Φ_B_P_P − V_f_l)/2.2. The comparative measurements of the electron temperature using BPP/LP and triple probe (TP) techniques on the ISTTOK tokamak show good agreement of averaged values only inside the separatrix. It was also found that the TP provides the electron temperature with significantly higher standard deviation than BPP/LP. However, the resulting values of both techniques are well in the phase with the maximum of cross-correlation function being 0.8.

  6. Fast-ion transport studies using FIDA spectroscopy at the ASDEX Upgrade tokamak

    International Nuclear Information System (INIS)

    Geiger, Benedikt

    2013-01-01

    A good confinement of fast-ions, i.e. ions with energies above the thermal energy, is essential for the success of fusion devices as it determines, amongst others, the plasma performance and the heating and current drive efficiencies. In case of a turbulent or magneto-hydrodynamic (MHD) active background plasma, various mechanisms have to be considered in order to estimate the spatial distribution of the fast-ions: the slowing down and radial diffusion by Coulomb collisions on electrons and ions, the effect of potential fluctuations and the effect of perturbations of the magnetic field structure. These can lead to a broadening of the fast-ion distribution function which is not yet completely understood. At the fusion experiment ASDEX Upgrade, the fast-ions are generated by heating sources such as neutral beam injection (NBI). Their transport properties can be studied by a fast-ion D-alpha (FIDA) spectroscopy diagnostic which has been built in the framework of this thesis. Through charge exchange reactions with neutrals, fast-ions can receive a bound electron and emit Balmer alpha line radiation. This so-called FIDA radiation can be measured with large Doppler shifts and is localized along the NBI path where a high density of neutrals is present. The FIDA diagnostic uses radially distributed lines of sight that intersect, in the horizontal and in the vertical plane, the path of a 2.5 MW NBI heating source. Thereby different parts of the fast-ion phase space above 25 keV can be analyzed. To interpret the FIDA radiation quantitatively, a forward modelling code has been implemented, tested and further developed. The code calculates, based on theoretical fast-ion distribution functions, synthetic FIDA spectra that can be compared to the measurement. In MHD-quiescent plasmas, the possible effect of turbulence on the fast-ion transport has been investigated with the FIDA diagnostic. The measurements obtained under different experimental conditions, such as during on- and

  7. Analysis of the H-mode density limit in the ASDEX upgrade tokamak using bolometry

    Energy Technology Data Exchange (ETDEWEB)

    Bernert, Matthias

    2013-10-23

    The high confinement mode (H-mode) is the operational scenario foreseen for ITER, DEMO and future fusion power plants. At high densities, which are favourable in order to maximize the fusion power, a back transition from the H-mode to the low confinement mode (L-mode) is observed. This H-mode density limit (HDL) occurs at densities on the order of, but below, the Greenwald density. In this thesis, the HDL is revisited in the fully tungsten walled ASDEX Upgrade tokamak (AUG). In AUG discharges, four distinct operational phases were identified in the approach towards the HDL. First, there is a stable H-mode, where the plasma density increases at steady confinement, followed by a degrading H-mode, where the core electron density is fixed and the confinement, expressed as the energy confinement time, reduces. In the third phase, the breakdown of the H-mode and transition to the L-mode, the overall electron density is fixed and the confinement decreases further, leading, finally, to an L-mode, where the density increases again at a steady confinement at typical L-mode values until the disruptive Greenwald limit is reached. These four phases are reproducible, quasi-stable plasma regimes and provide a framework in which the HDL can be further analysed. Radiation losses and several other mechanisms, that were proposed as explanations for the HDL, are ruled out for the current set of AUG experiments with tungsten walls. In addition, a threshold of the radial electric field or of the power flux into the divertor appears to be responsible for the final transition back to L-mode, however, it does not determine the onset of the HDL. The observation of the four phases is explained by the combination of two mechanisms: a fueling limit due to an outward shift of the ionization profile and an additional energy loss channel, which decreases the confinement. The latter is most likely created by an increased radial convective transport at the edge of the plasma. It is shown that the

  8. Analysis of the H-mode density limit in the ASDEX upgrade tokamak using bolometry

    International Nuclear Information System (INIS)

    Bernert, Matthias

    2013-01-01

    The high confinement mode (H-mode) is the operational scenario foreseen for ITER, DEMO and future fusion power plants. At high densities, which are favourable in order to maximize the fusion power, a back transition from the H-mode to the low confinement mode (L-mode) is observed. This H-mode density limit (HDL) occurs at densities on the order of, but below, the Greenwald density. In this thesis, the HDL is revisited in the fully tungsten walled ASDEX Upgrade tokamak (AUG). In AUG discharges, four distinct operational phases were identified in the approach towards the HDL. First, there is a stable H-mode, where the plasma density increases at steady confinement, followed by a degrading H-mode, where the core electron density is fixed and the confinement, expressed as the energy confinement time, reduces. In the third phase, the breakdown of the H-mode and transition to the L-mode, the overall electron density is fixed and the confinement decreases further, leading, finally, to an L-mode, where the density increases again at a steady confinement at typical L-mode values until the disruptive Greenwald limit is reached. These four phases are reproducible, quasi-stable plasma regimes and provide a framework in which the HDL can be further analysed. Radiation losses and several other mechanisms, that were proposed as explanations for the HDL, are ruled out for the current set of AUG experiments with tungsten walls. In addition, a threshold of the radial electric field or of the power flux into the divertor appears to be responsible for the final transition back to L-mode, however, it does not determine the onset of the HDL. The observation of the four phases is explained by the combination of two mechanisms: a fueling limit due to an outward shift of the ionization profile and an additional energy loss channel, which decreases the confinement. The latter is most likely created by an increased radial convective transport at the edge of the plasma. It is shown that the

  9. Real-time control of the plasma density profile on ASDEX upgrade

    International Nuclear Information System (INIS)

    Mlynek, Alexander

    2010-01-01

    The tokamak concept currently is the most promising approach to future power generation by controlled thermonuclear fusion. The spatial distribution of the particle density in the toroidally confined fusion plasma is of particular importance. This thesis work therefore focuses on the question as to what extent the shape of the density profile can be actively controlled by a feedback loop in the fusion experiment ASDEX Upgrade. There are basically two essential requirements for such feedback control of the density profile, which has been experimentally demonstrated within the scope of this thesis work: On the one hand, for this purpose the density profile must be continuously calculated under real-time constraints during a plasma discharge. The calculation of the density profile is based on the measurements of a sub-millimeter interferometer, which provides the line-integrated electron density along 5 chords through the plasma. Interferometric density measurements can suffer from counting errors by integer multiples of 2π when detecting the phase difference between a probing and a reference beam. As such measurement errors have severe impact on the reconstructed density profile, one major part of this work consists in the development of new readout electronics for the interferometer, which allows for detection of such measurement errors in real-time with high reliability. A further part of this work is the design of a computer algorithm which reconstructs the spatial distribution of the plasma density from the line-integrated measurements. This algorithm has to be implemented on a computer which communicates the measured data to other computers in real-time, especially to the tokamak control system. On the other hand, a second fundamental requirement for the successful implementation of a feedback controller is the identification of at least one actuator which enables a modification of the density profile. Here, electron cyclotron resonance heating (ECRH) has been

  10. Investigation of local carbon transport in the ASDEX Upgrade divertor using {sup 13}CH{sub 4} puffing

    Energy Technology Data Exchange (ETDEWEB)

    Pugno, R. [Max-Planck-Institut fuer Plasmaphysik, IPP-EURATOM Association, Boltzmannstr. 2, D-85748 Garching (Germany)], E-mail: Roberto.Pugno@ipp.mpg.de; Krieger, K. [Max-Planck-Institut fuer Plasmaphysik, IPP-EURATOM Association, Boltzmannstr. 2, D-85748 Garching (Germany); Airila, M.; Aho-Mantila, L. [Helsinki University of Technology, Association EURATOM-Tekes, P.O. Box 4100, FI-02015 TKK (Finland); Kreter, A.; Brezinsek, S. [Institut fuer Plasmaphysik, Forschungzentrum Juelich GmbH, EURATOM Association, Trilateral Euregio Cluster, D-52425 Juelich (Germany); Rohde, V.; Coster, D.; Chankin, A.; Wischmeier, M. [Max-Planck-Institut fuer Plasmaphysik, IPP-EURATOM Association, Boltzmannstr. 2, D-85748 Garching (Germany)

    2009-06-15

    To investigate the combined effect of re-deposition, re-erosion and local transport, known quantities of {sup 13}CH{sub 4} were puffed at the end of the 2007 experimental campaign in the ASDEX Upgrade outboard divertor. Exposed tiles were carefully removed for analysis. The amount of {sup 13}C locally deposited was measured by nuclear reaction analysis (NRA) and colorimetry. About 100% of injected carbon is deposited within a {+-} 15 cm extension in the toroidal direction. In contrast to H-mode results where re-deposition was exclusively downstream, in L-mode, more than one third of the injected hydrocarbon is found upstream. Colorimetric analysis of images taken with different lighting angles to the surface reveals a strong asymmetry in the carbon deposition pattern with respect to the injection facing/averting side of the surface roughness, with 4x thicker layers on the side facing the puffing location. The deposition pattern deviates clearly from the magnetic trajectories showing the effect of downward and radial drifts. ERO modelling of a similar experiment carried out in 2003 in H-mode background plasma can nicely reproduce the toroidal deposition pattern but drifts are not yet satisfactory described.

  11. Stability and propagation of the high field side high density front in the fluctuating state of detachment in ASDEX Upgrade

    Directory of Open Access Journals (Sweden)

    P. Manz

    2017-08-01

    Full Text Available During detachment a structure of strongly enhanced density develops close to the inner target. Its dynamics is approximated by those of radiative fluctuations appearing at a similar position and studied by means of a time-delay-estimation technique in the ASDEX Upgrade tokamak. Compared to theory the dynamics can be described as follows: at increasing density the ionization front moves upstream to reduce ionization radiation in order to balance the increased recombination radiation. The recombination zone stays close to the target strike point. The parallel motion of the ionization front is determined by the perpendicular neutral motion. The divertor nose constitutes an obstacle for the perpendicular neutral flux from the target to the region above the X-point. Passing into this shadow the neutral flux above the X-point is strongly reduced, the ionization front fades away and the heat flux from upstream can increase the temperature in the recombination region, subsequently reducing recombination and reforming an ionization front below the X-point. A cyclic reformation of the ionization front propagating from below to above the X-point occurs leading to a fluctuation as observed in the experiment.

  12. Data acquisition and real-time signal processing of plasma diagnostics on ASDEX Upgrade using LabVIEW RT

    International Nuclear Information System (INIS)

    Giannone, L.; Cerna, M.; Cole, R.; Fitzek, M.; Kallenbach, A.; Lueddecke, K.; McCarthy, P.J.; Scarabosio, A.; Schneider, W.; Sips, A.C.C.; Treutterer, W.; Vrancic, A.; Wenzel, L.; Yi, H.; Behler, K.; Eich, T.; Eixenberger, H.; Fuchs, J.C.; Haas, G.; Lexa, G.

    2010-01-01

    The existing VxWorks real-time system for the position and shape control in ASDEX Upgrade has been extended to calculate magnetic flux surfaces in real-time using a multi-core PCI Express system running LabVIEW RT 8.6. real-time signal processing of bolometers and manometers is performed with the on-board FPGA to calculate the measured radiated power flux and particle flux respectively from the raw data. Radiation feedback experiments use halo current measurements from the outer divertor with real-time median filter pre-processing to remove the excursions produced by ELMs. Integration of these plasma diagnostics into the control system by the exchange of XML sheets for communicating the real-time variables to be produced and consumed is in operation. Reflective memory and UDP are employed by the LabVIEW RT plasma diagnostics to communicate with the control system and other plasma diagnostics in a multi-platform real-time network.

  13. Data acquisition and real-time signal processing of plasma diagnostics on ASDEX Upgrade using LabVIEW RT

    Energy Technology Data Exchange (ETDEWEB)

    Giannone, L., E-mail: Louis.Giannone@ipp.mpg.d [Max-Planck-Institut fuer Plasmaphysik, EURATOM-IPP Association, D-85748 Garching (Germany); Cerna, M. [National Instruments, Austin, TX 78759-3504 (United States); Cole, R.; Fitzek, M. [Unlimited Computer Systems GmbH, 82393 Iffeldorf (Germany); Kallenbach, A. [Max-Planck-Institut fuer Plasmaphysik, EURATOM-IPP Association, D-85748 Garching (Germany); Lueddecke, K. [Unlimited Computer Systems GmbH, 82393 Iffeldorf (Germany); McCarthy, P.J. [Department of Physics, University College Cork, Association EURATOM-DCU, Cork (Ireland); Scarabosio, A.; Schneider, W.; Sips, A.C.C.; Treutterer, W. [Max-Planck-Institut fuer Plasmaphysik, EURATOM-IPP Association, D-85748 Garching (Germany); Vrancic, A.; Wenzel, L.; Yi, H. [National Instruments, Austin, TX 78759-3504 (United States); Behler, K.; Eich, T.; Eixenberger, H.; Fuchs, J.C.; Haas, G.; Lexa, G. [Max-Planck-Institut fuer Plasmaphysik, EURATOM-IPP Association, D-85748 Garching (Germany)

    2010-07-15

    The existing VxWorks real-time system for the position and shape control in ASDEX Upgrade has been extended to calculate magnetic flux surfaces in real-time using a multi-core PCI Express system running LabVIEW RT 8.6. real-time signal processing of bolometers and manometers is performed with the on-board FPGA to calculate the measured radiated power flux and particle flux respectively from the raw data. Radiation feedback experiments use halo current measurements from the outer divertor with real-time median filter pre-processing to remove the excursions produced by ELMs. Integration of these plasma diagnostics into the control system by the exchange of XML sheets for communicating the real-time variables to be produced and consumed is in operation. Reflective memory and UDP are employed by the LabVIEW RT plasma diagnostics to communicate with the control system and other plasma diagnostics in a multi-platform real-time network.

  14. Mechanical braking system for the pulsed power supply system of ASDEX Upgrade

    International Nuclear Information System (INIS)

    Käsemann, C.-P.; Huart, M.; Stobbe, F.; Goldstein, I.; Sigalov, A.; Sachs, E.; Perk, E.

    2013-01-01

    Highlights: ► Compact and innovative solution for dumping of large kinetic energy. ► Small mass of energy converter at the shaft due to circulating storage medium. ► Design of the active parts ensures flat torque/power characteristics. ► Also suitable for spending a great part of operating life in “Freewheeling” mode. -- Abstract: A few years ago, IPP reviewed the safety of the ASDEX Upgrade pulsed power supply system. Two critical sub-systems had been identified: The (electrical) braking system for the flywheel generators and the oil lubrication system for the shaft bearings. A simultaneous failure of these two systems may lead to severe damages and could have consequences for the safety of operating personnel. Therefore a second, independent braking possibility for every generator was stipulated. Especially the challenges adapting a dynamometer, originally designed for motor test benches, towards a plant safety system for generator EZ4 will be described in the paper. Further on, the paper will present the problems, implementing such a system into an existing installation, including the calculation of the required supporting structure, balancing of the extended shaft line and required water cooling and control. Finally it will report on the performance achieved during operation

  15. Fast-ion losses induced by ACs and TAEs in the ASDEX Upgrade tokamak

    International Nuclear Information System (INIS)

    GarcIa-Munoz, M.; Hicks, N.; Classen, I.G.J.; Bilato, R.; Bobkov, V.; Brambilla, M.; Bruedgam, M.; Fahrbach, H.-U.; Igochine, V.; Maraschek, M.; Sassenberg, K.; Van Voornveld, R.; Jaemsae, S.

    2010-01-01

    The phase-space of convective and diffusive fast-ion losses induced by shear Alfven eigenmodes has been characterized in the ASDEX Upgrade tokamak. Time-resolved energy and pitch-angle measurements of fast-ion losses correlated in frequency and phase with toroidal Alfven eigenmodes (TAEs) and Alfven cascades (ACs) have allowed to identify both loss mechanisms. While single ACs and TAEs eject resonant fast-ions in a convective process, the overlapping of AC and TAE spatial structures leads to a large fast-ion diffusion and loss. The threshold for diffusive fast-ion losses depends on the ion energy (gyroradius). Diffusive fast-ion losses with gyroradius ∼70 mm have been observed with a single TAE for local radial displacements of the magnetic field lines larger than ∼2 mm. Multiple frequency chirping ACs cause an enhancement of the diffusive losses. The ACs and TAEs radial structures have been reconstructed by means of cross-correlation techniques between the fast-ion loss detector and the electron cyclotron emission radiometer.

  16. Radial correlation length measurements on ASDEX Upgrade using correlation Doppler reflectometry

    International Nuclear Information System (INIS)

    Schirmer, J; Conway, G D; Holzhauer, E; Suttrop, W; Zohm, H

    2007-01-01

    The technique of correlation Doppler reflectometry for providing radial correlation length L r measurements is explored in this paper. Experimental L r measurements are obtained using the recently installed dual channel Doppler reflectometer system on ASDEX Upgrade. The experimental measurements agree well with theory and with L r measured on other fusion devices using different diagnostic techniques. A strong link between L r and plasma confinement could be observed. From the L- to the H-mode, an increase in the absolute value of E r shear was detected at the same plasma edge region where a decrease in L r was measured. This observation is in agreement with theoretical models which predict that an increase in the absolute shear suppresses turbulent fluctuations in the plasma, leading to a reduction in L r . Furthermore, L r decreases from the plasma core to the edge and decreases with increasing plasma triangularity δ. The experimental results have been extensively modelled using a 2-dimensional finite difference time domain code. The simulations confirm that Doppler reflectometry provides robust radial correlation lengths of the turbulence with high resolution and suggests that L r is independent of the turbulence wavenumber k p erpendicular and its fluctuation level

  17. Intermittent transport across the scrape-off layer: latest results from ASDEX Upgrade

    International Nuclear Information System (INIS)

    Kočan, M.; Müller, H.W.; Lunt, T.; Bernert, M.; Conway, G.D.; De Marné, P.; Eich, T.; Herrmann, A.; Kallenbach, A.; Maraschek, M.; Müller, S.; Nold, B.; Huang, Z.; Adámek, J.; Horacek, J.; Komm, M.; Allan, S.Y.; Elmore, S.; Gennrich, F.P; Mehlmann, F.

    2013-01-01

    We report the latest results of turbulence and transport studies in the ASDEX Upgrade scrape-off layer (SOL). Dissimilarity between the plasma and the floating potential fluctuations is studied experimentally and by gyrofluid simulations. Measurements by a retarding field analyser reveal that both, edge-localized mode (ELM) and turbulent filaments, convey hot ions over large radial distances in the SOL. The measured far SOL ELM ion temperature increases with the ELM energy, consistent with earlier observations that large ELMs deposit a large fraction of their energy outside the divertor. In the SOL, the ELM suppression by magnetic perturbations (MPs) results in lower ELM ion energy in the far SOL. At the same time, large filaments of ion saturation current are replaced by more continuous bursts. Splitting of the divertor strike zones observed by the infrared imaging in H-mode with MPs agree with predictions from the EMC3-Eirene simulations. This suggests that the ‘lobe’ structures due to perturbation fields observed near the X-point are not significantly affected by plasma screening, and can be described by a vacuum approach, as in the EMC3-Eirene. Finally, some effects of the MPs on the L-mode SOL are addressed. (paper)

  18. A new algorithm to determine the total radiated power at ASDEX upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Gloeggler, Stephan; Bernert, Matthias; Eich, Thomas [Max Planck Institute for Plasma Physics, Boltzmannstr. 2, 85748 Garching (Germany); Collaboration: The ASDEX Upgrade Team

    2016-07-01

    Radiation is an essential part of the power balance in a fusion plasma. In future fusion devices about 90% of the power will have to be dissipated, mainly by radiation. For the development of an appropriate operational scenario, information about the absolute level of plasma radiation (P{sub rad,tot}) is crucial. Bolometers are used to measure the radiated power, however, an algorithm is required to derive the absolute power out of many line-integrated measurements. The currently used algorithm (BPD) was developed for the main chamber radiation. It underestimates the divertor radiation as its basic assumptions are not satisfied in this region. Therefore, a new P{sub rad,tot} algorithm is presented. It applies an Abel inversion on the main chamber and uses empirically based assumptions for poloidal asymmetries and the divertor radiation. To benchmark the new algorithm, synthetic emissivity profiles are used. On average, the new Abel inversion based algorithm deviates by only 10% from the nominal synthetic value while BPD is about 25% too low. With both codes time traces of ASDEX Upgrade discharges are calculated. The analysis of these time traces shows that the underestimation of the divertor radiation can have significant consequences on the accuracy of BPD while the new algorithm is shown to be stable.

  19. 2D heat flux pattern in ASDEX upgrade L-mode with magnetic perturbation

    Energy Technology Data Exchange (ETDEWEB)

    Faitsch, Michael; Sieglin, Bernhard; Eich, Thomas; Herrmann, Albrecht; Suttrop, Wolfgang [Max-Planck-Institute for Plasma Physics, Boltzmannstr. 2, D-85748 Garching (Germany); Collaboration: the ASDEDX Upgrade Team

    2016-07-01

    A future fusion reactor is likely to operate in high confinement mode (H-mode). This mode is associated with a periodic instability at the plasma edge that expels particles and energy. This instability is called edge localized mode (ELM). External magnetic perturbation (MP) is one technique that is thought to be able to mitigate or even suppress large ELMs in next step fusion devices such as ITER, where the ELM induced heat load for unmitigated ELMs might limit the lifetime of the divertor. Applying an external magnetic perturbation breaks the axisymmetry and leads to a 2D steady state heat flux pattern at the divertor. The ASDEX Upgrade tokamak is equipped with 16 perturbation coils, 8 above (upper row) and 8 below (lower row) the outer mid plane, toroidal equally distributed. A high resolution infra red system is measuring the heat flux at the outer target at a fixed toroidal position with a resolution of around 0.6 mm. In order to measure the 2D structure a slow rotation of the MP field was applied (1 Hz) with a toroidal mode number n=2. The differential phase between the upper and lower row was changed to investigate the effect of the alignment with the field lines at the edge. The density was varied to study the density dependence of the heat transport with applied external MP and compare it to the axisymmetric scenario.

  20. Induced tungsten melting events in the divertor of ASDEX Upgrade and their influence on plasma performance

    International Nuclear Information System (INIS)

    Krieger, K.; Lunt, T.; Dux, R.; Janzer, A.; Kallenbach, A.; Mueller, H.W.; Neu, R.; Puetterich, T.; Rohde, V.

    2011-01-01

    Tungsten rods of 1 x 1 x 3 mm were exposed at the outer divertor plate of ASDEX Upgrade using a manipulator system. Controlled melting of the W-rod in H-mode discharges was induced by moving the outer strike point towards the W-rod position. Visible light emission of ejected W droplets was recorded by fast camera systems. The resulting increase of tungsten concentration in the confined plasma was compared to that induced by W laser ablation into the outer main chamber boundary plasma. The resulting divertor retention expressed as ratio of tungsten core penetration probability from a divertor source to that of a main chamber source is ∼100. Ejected droplets are found to move always in general direction of the plasma flow. The measured magnitude of droplet acceleration shows that droplets are mainly subject to rocket forces and friction forces. Typical initial droplet size can be inferred from the time evolution of the droplet light emission to be ≥100μm.

  1. Low-Z impurity transport studies using CXRS at ASDEX upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Bruhn, Cecilia; McDermott, Rachael; Dux, Ralph; Angioni, Clemente; Bobkov, Volodymyr; Kappatou, Athina; Lebschy, Alexander; Puetterich, Thomas; Viezzer, Eleonora [Max-Planck-Institut fuer Plasmaphysik, Boltzmannstr. 2, D-85748 Garching (Germany); Collaboration: the ASDEX Upgrade Team

    2016-07-01

    Impurities in fusion plasmas arise from many sources including the erosion of material from plasma facing components and the intentional injection of impurities for control of the radiation losses. With the charge exchange recombination spectroscopy (CXRS) diagnostics at ASDEX Upgrade (AUG) the density profiles of low-Z impurity species can be measured with high spatial and temporal resolution and can, thus, be used to investigate the transport of these impurities. Previous work on this topic at AUG has focused primarily on steady state profiles, which deliver the ratio of the diffusive and convective transport coefficients. However, from the time response of the density profiles after applying an external perturbation (e.g. a fast impurity puff) the convective and diffusive components of the transport can be separately determined. The work presented here aims to achieve this by a less conventional approach that is better suited to the limited time resolution of the CXRS diagnostics; namely, a sinusoidal modulation of the boron densities invoked by modulating the power from the ion cyclotron resonance frequency (ICRF) antennas. The work presented here aims to achieve this by an approach that is better suited to the limited time resolution of the CXRS diagnostics; namely, a sinusoidal modulation of the boron densities invoked by modulating the power from the ion cyclotron resonance frequency (ICRF) antennas. We present the first measurements of the boron density modulation as well as the machine and plasma parameter dependencies of the boron response to the ICRF power.

  2. Interpretation of the electron cyclotron emission of hot ASDEX upgrade plasmas at optically thin frequencies

    Energy Technology Data Exchange (ETDEWEB)

    Denk, Severin Sebastian; Stroth, Ulrich [Max-Planck-Institut fuer Plasmaphysik, D-85748 Garching (Germany); Physik-Department E28, Technische Universitaet Muenchen, 85748 Garching (Germany); Fischer, Rainer; Poli, Emanuele; Willensdorfer, Matthias; Maj, Omar; Stober, Joerg; Suttrop, Wolfgang [Max-Planck-Institut fuer Plasmaphysik, D-85748 Garching (Germany); Collaboration: The ASDEX Upgrade Team

    2016-07-01

    The electron cyclotron emission diagnostic (ECE) provides routinely electron temperature (T{sub e}) measurements. ''Kinetic effects'' (relativistic mass shift and Doppler shift) can cause the measured radiation temperatures (T{sub rad}) to differ from T{sub e} at cold resonance position complicating the determination of T{sub e} from the measured radiation temperature profile (T{sub rad}). For the interpretation of such ECE measurements an electron cyclotron forward model solving the radiation transport equation for given T{sub e} and electron density profiles is in use in the framework of Integrated Data Analysis at ASDEX Upgrade. While the original model lead to improved T{sub e} profiles near the plasma edge in moderately hot H-mode discharges, vacuum approximations in the model lead to inaccuracies given large T{sub e}. In hot plasmas ''wave-plasma interaction'', i.e. the dielectric effect of the background plasma onto the electron cyclotron emission, becomes important at optical thin measured frequencies. Additionally, given moderate electron densities and large T{sub e}, the refraction of the line of sight has to be considered for the interpretation of ECE measurements with low optical depth.

  3. Optimized tokamak power exhaust with double radiative feedback in ASDEX Upgrade

    Science.gov (United States)

    Kallenbach, A.; Bernert, M.; Eich, T.; Fuchs, J. C.; Giannone, L.; Herrmann, A.; Schweinzer, J.; Treutterer, W.; the ASDEX Upgrade Team

    2012-12-01

    A double radiative feedback technique has been developed on the ASDEX Upgrade tokamak for optimization of power exhaust with a standard vertical target divertor. The main chamber radiation is measured in real time by a subset of three foil bolometer channels and controlled by argon injection in the outer midplane. The target heat flux is in addition controlled by nitrogen injection in the divertor private flux region using either a thermoelectric sensor or the scaled divertor radiation obtained by a bolometer channel in the outer divertor. No negative interference of the two radiation controllers has been observed so far. The combination of main chamber and divertor radiative cooling extends the operational space of a standard divertor configuration towards high values of P/R. Pheat/R = 14 MW m-1 has been achieved so far with nitrogen seeding alone as well as with combined N + Ar injection, with the time-averaged divertor peak heat flux below 5 MW m-2. Good plasma performance can be maintained under these conditions, namely H98(y,2) = 1 and βN = 3.

  4. Active Control of Power Exhaust in Strongly Heated ASDEX Upgrade Plasmas

    Science.gov (United States)

    Dux, Ralph; Kallenbach, Arne; Bernert, Matthias; Eich, Thomas; Fuchs, Christoph; Giannone, Louis; Herrmann, Albrecht; Schweinzer, Josef; Treutterer, Wolfgang

    2012-10-01

    Due to the absence of carbon as an intrinsic low-Z radiator, and tight limits for the acceptable power load on the divertor target, ITER will rely on impurity seeding for radiative power dissipation and for generation of partial detachment. The injection of more than one radiating species is required to optimise the power removal in the main plasma and in the divertor region, i.e. a low-Z species for radiation in the divertor and a medium-Z species for radiation in the outer core plasma. In ASDEX Upgrade, a set of robust sensors, which is suitable to feedback control the radiated power in the main chamber and the divertor as well as the electron temperature at the target, has been developed. Different feedback schemes were applied in H-mode discharges with a maximum heating power of up to 23,W, i.e. at ITER values of P/R (power per major radius) to control all combinations of power flux into the divertor region, power flux onto the target or electron temperature at the target through injection of nitrogen as the divertor radiator and argon as the main chamber radiator. Even at the highest heating powers the peak heat flux density at the target is kept at benign values. The control schemes and the plasma behaviour in these discharges will be discussed.

  5. Spectroscopic measurement of target plate erosion in the ASDEX Upgrade divertor

    Energy Technology Data Exchange (ETDEWEB)

    Filed, A R; Garcia-Rosales, C; Lieder, G; Pitcher, C S; Radtke, R [Association Euratom-Max-Planck-Institut fuer Plasmaphysik, Garching (Germany); ASDEX Upgrade Team

    1996-02-01

    The erosion of the graphite divertor plates in the ASDEX Upgrade tokamak is measured spectroscopically. Spatial profiles of the D{sup 0} and C{sup +} influxes across the outer target plate are determined from measured absolute line intensities. Plasma parameters (n{sub e}, T{sub e}) at the target, which are required to determine the appropriate photon emission efficiencies for these lines, are obtained from an in-vessel reciprocating Langmuir probe above the target plate. Yields for the erosion of the graphite by the incident D{sup +} flux are determined from the ratio of the measured C{sup +} to D{sup 0} fluxes. Over a range of moderate densities the measured yields of {<=} 4% are explicable in terms of physical sputtering alone. Chemical sputtering by low energy Franck-Condon neutrals probably contributes, however, to the total erosion. At higher densities detachment of the plasma from the targets occurs owing to formation of a MARFE near the X point. Under these conditions localized physical sputtering of the targets ceases. The impurity level (Z{sub eff}) is, however, maintained following detachment, indicating a corresponding maintenance of carbon influx, perhaps due to chemical erosion of the total graphite surface and/or an improvement in particle confinement in the detached state. (author). 26 refs, 14 figs, 1 tab.

  6. Transport analysis of high radiation and high density plasmas in the ASDEX Upgrade tokamak

    Directory of Open Access Journals (Sweden)

    Casali L.

    2014-01-01

    Full Text Available Future fusion reactors, foreseen in the “European road map” such as DEMO, will operate under more demanding conditions compared to present devices. They will require high divertor and core radiation by impurity seeding to reduce heat loads on divertor target plates. In addition, DEMO will have to work at high core densities to reach adequate fusion performance. The performance of fusion reactors depends on three essential parameters: temperature, density and energy confinement time. The latter characterizes the loss rate due to both radiation and transport processes. The DEMO foreseen scenarios described above were not investigated so far, but are now addressed at the ASDEX Upgrade tokamak. In this work we present the transport analysis of such scenarios. Plasma with high radiation by impurity seeding: transport analysis taking into account the radiation distribution shows no change in transport during impurity seeding. The observed confinement improvement is an effect of higher pedestal temperatures which extend to the core via stiffness. A non coronal radiation model was developed and compared to the bolometric measurements in order to provide a reliable radiation profile for transport calculations. High density plasmas with pellets: the analysis of kinetic profiles reveals a transient phase at the start of the pellet fuelling due to a slower density build up compared to the temperature decrease. The low particle diffusion can explain the confinement behaviour.

  7. Mechanical braking system for the pulsed power supply system of ASDEX Upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Käsemann, C.-P., E-mail: c.p.kaesemann@ipp.mpg.de [Max Planck Institute for Plasma Physics, EURATOM Association, Boltzmannstr. 2, 85748 Garching (Germany); Huart, M. [Max Planck Institute for Plasma Physics, EURATOM Association, Boltzmannstr. 2, 85748 Garching (Germany); Michel Huart Personal Coaching and Consulting, Georgenschwaigstraße 23 RG, 80807 München (Germany); Stobbe, F.; Goldstein, I.; Sigalov, A. [Max Planck Institute for Plasma Physics, EURATOM Association, Boltzmannstr. 2, 85748 Garching (Germany); Sachs, E. [Siemens AG, Industrial Automation Systems, Gleiwitzer Straße 555, 90475 Nürnberg (Germany); Perk, E. [Piper Test and Measurement Ltd., The Barn, Bilsington, Ashford, Kent TN25 7JT, England (United Kingdom)

    2013-10-15

    Highlights: ► Compact and innovative solution for dumping of large kinetic energy. ► Small mass of energy converter at the shaft due to circulating storage medium. ► Design of the active parts ensures flat torque/power characteristics. ► Also suitable for spending a great part of operating life in “Freewheeling” mode. -- Abstract: A few years ago, IPP reviewed the safety of the ASDEX Upgrade pulsed power supply system. Two critical sub-systems had been identified: The (electrical) braking system for the flywheel generators and the oil lubrication system for the shaft bearings. A simultaneous failure of these two systems may lead to severe damages and could have consequences for the safety of operating personnel. Therefore a second, independent braking possibility for every generator was stipulated. Especially the challenges adapting a dynamometer, originally designed for motor test benches, towards a plant safety system for generator EZ4 will be described in the paper. Further on, the paper will present the problems, implementing such a system into an existing installation, including the calculation of the required supporting structure, balancing of the extended shaft line and required water cooling and control. Finally it will report on the performance achieved during operation.

  8. Operational limits of high density H-modes in ASDEX Upgrade

    International Nuclear Information System (INIS)

    Mertens, V.; Borrass, K.; Kaufmann, M.; Lang, P.T.; Lang, R.; Mueller, H.W.; Neuhauser, J.; Schneider, R.; Schweinzer, J.; Suttrop, W.

    2001-01-01

    Systematic investigations of H-mode density limit (H→L-mode back transition) plasmas with gas fuelling and alternatively with additional pellet injection from the magnetic high-field-side HFS are being performed in the new closed divertor configuration DV-II. The resulting database covering a wide range of the externally controllable plasma parameters I p , B t and P heat confirms that the H-mode threshold power exceeds the generally accepted prediction P L→H heat ∝B-bar t dramatically when one approaches Greenwald densities. Additionally, in contrast to the Greenwald scaling a moderate B t -dependence of the H-mode density limit is found. The limit is observed to coincide with divertor detachment and a strong increase of the edge thermal transport, which has, however, no detrimental effect on global τ E . The pellet injection scheme from the magnetic high-field-side HFS, developed recently on ASDEX Upgrade, leads to fast particle drifts which are, contrary to the standard injection from the low-field-side, directed into the plasma core. This improves markedly the pellet particle fuelling efficiency. The responsible physical mechanism, the diamagnetic particle drift of the pellet ablatant was successfully verified recently. Other increased particle losses on respectively different time scales after the ablation process, however, still persist. Generally, a clear gain in achievable density and plasma stored energy is achieved with stationary HFS pellet injection compared to gas-puffing. (author)

  9. Numerical simulations of fast ion loss measurements induced by magnetic islands in the ASDEX Upgrade tokamak

    International Nuclear Information System (INIS)

    Gobbin, M.; Marrelli, L.; Martin, P.; Fahrbach, H.U.; Garcia-Munoz, M.; Guenter, S.; White, R.B.

    2009-01-01

    A test particle approach, implemented with the Hamiltonian code ORBIT, is used to simulate measurements of fast ion losses induced by magnetic islands in the ASDEX Upgrade tokamak. In particular, the numerical simulations reproduce the toroidal localization of losses and the lost ions pitch angle and energy distribution experimentally measured with the fast ion losses detector (FILD) in the presence of a neoclassical tearing mode (NTM). The simulated NTM induced losses occurring on time scales longer than 100 μs are composed of mainly trapped or barely passing particles, consistently with the slow decay of the experimental signal from one FILD channel after the beam switch-off. The numerical simulations have been performed by taking into account the D-shaped plasma geometry, the collision mechanisms, the losses due to ripple effects and the rotation of the mode. The radial profile of the magnetic perturbation is adjusted in order to match ECE measurements. While statistical properties of FILD measurements are rather well reproduced, the simulated total amount of losses is found to be significantly affected by edge details of the magnetic perturbation as it determines the loss mechanism.

  10. Manufacture of New Set of Calorimeter Panels for the Neutral Beam Injection of ASDEX Upgrade

    International Nuclear Information System (INIS)

    Huber, T.; Zabernig, A.; Riedel, R.; Schedler, B.; Froeschle, M.; Heinemann, B.; Entcheva, A.; Weigert, J.

    2006-01-01

    The Neutral Injection of ASDEX-Upgrade employs calorimeter panels to measure the power of the neutral beam. These components are designed to safely absorb specific heat flux loads as high as 25 MW/m 2 over a period of 10 s. The currently used calorimeter panels have reached after ten years the end of their service life time and have to be replaced. The components consist of the CuCrZr which is a precipitation hardened alloy. The selection of the manufacturing process therefore determines the final thermal and mechanical properties of the alloy. In the past these components were manufactured by a two step brazing process, at about 830 o C and 730 o C, respectively. This led to an overaging of the material resulting in low mechanical properties. As predicted by finite element calculations the cyclic heat flux load leads to ratcheting at the heated surface finally limiting the life time of the components. In order to increase the service life time of the component it has therefore been decided to employ electron beam welding as the only joining technique to realise the required joints of the components. To fully characterise this manufacturing route a qualification programme has been performed, which ended in the manufacture of prototypes. These have been tested in ASEDEX Upgrade in comparison to brazed components. After successful qualification of design and processes the manufacture and testing of 100 calorimeter panels has been launched and completed recently. The used design, the results of the qualification tests, the manufacturing sequence and the applied non-destructive methods will be described in the paper. (author)

  11. Measurement of the complete core plasma flow across the LOC-SOC transition at ASDEX Upgrade

    Science.gov (United States)

    Lebschy, A.; McDermott, R. M.; Angioni, C.; Geiger, B.; Prisiazhniuk, D.; Cavedon, M.; Conway, G. D.; Dux, R.; Dunne, M. G.; Kappatou, A.; Pütterich, T.; Stroth, U.; Viezzer, E.; the ASDEX Upgrade Team

    2018-02-01

    A newly installed core charge exchange recombination spectroscopy (CXRS) diagnostic at ASDEX Upgrade (AUG) enables the evaluation of the core poloidal rotation (upol ) through the inboard-outboard asymmetry of the toroidal rotation with an accuracy of 0.5 to 1 km s-1 . Using this technique, the total plasma flow has been measured in Ohmic L-mode plasmas across the transition from the linear to saturated ohmic confinement (LOC-SOC) regimes. The core poloidal rotation of the plasma around mid-radius is found to be always in the ion diamagnetic direction, in disagreement with neoclassical (NC) predictions. The edge rotation is found to be electron-directed and consistent with NC codes. This measurement provides as well the missing ingredient to evaluate the core E×B velocity (uE×B ) from data only, which can then be compared to measurements of the perpendicular velocity of the turbulent fluctuations (u\\perp ) to gain information on the turbulent phase velocity (vph ). The non neoclassical upol from CXRS leads to good agreement between uE×B and u\\perp indicating that vph is small and at similar values as found with gyrokinetic simulations. Moreover, the data shows a shift of vph in the ion-diamagnetic direction at the edge after the transition from LOC to SOC consistent with a change in the dominant turbulence regime. The upgrade of the core CXRS system provides as well a deeper insight into the intrinsic rotation. This paper shows that the reversal of the core toroidal rotation occurs clearly after the LOC-SOC transition and concomitant with the peaking of the electron density.

  12. A new beam emission polarimetry diagnostic for measuring the magnetic field line angle at the plasma edge of ASDEX Upgrade.

    Science.gov (United States)

    Viezzer, E; Dux, R; Dunne, M G

    2016-11-01

    A new edge beam emission polarimetry diagnostic dedicated to the measurement of the magnetic field line angle has been installed on the ASDEX Upgrade tokamak. The new diagnostic relies on the motional Stark effect and is based on the simultaneous measurement of the polarization direction of the linearly polarized π (parallel to the electric field) and σ (perpendicular to the electric field) lines of the Balmer line D α . The technical properties of the system are described. The calibration procedures are discussed and first measurements are presented.

  13. Generation and analysis of plasmas with centrally reduced helicity in full-tungsten ASDEX upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Bock, Alexander

    2016-03-01

    The most promising concepts for harnessing nuclear fusion are toroidal devices like tokamaks, where a plasma is confined by helically twisted magnetic field lines. To provide the twisting of the field lines, a tokamak relies on a toroidal current in the plasma, which is largely generated by a transformer. As such, conventional tokamaks are limited to pulsed operation. Moreover, this current makes tokamak plasmas prone to numerous confinement degrading magnetohydrodynamic (MHD) instabilities that can emerge at locations where the field line helicity q takes on rational values like 1/1, 3/2 or 2/1, i.e. sawteeth or neoclassical tearing modes (NTMs). This thesis presents studies of plasmas with centrally elevated q-profiles created by external electron-cyclotron and neutral beam current drive (ECCD/NBCD) under steady-state conditions in the full-tungsten tokamak ASDEX Upgrade. Without the usually monotonic q-profile, instabilities of low helicity disappear, thereby improving the plasma stability. Furthermore, elevating q increases the amount of so-called (toroidal) bootstrap current, which the plasma drives by itself in the presence of pressure gradients, thereby reducing the reliance on the transformer. In the best case, an advanced tokamak (AT) could thus run in steady state. Additionally, an elevated and thus flat/slightly reversed q-profile is thought to improve confinement by impeding turbulent transport. Reconstruction of the tailored q-profile is accomplished with the new integrated data equilibrium (IDE) code and information from a key diagnostic that is based on the Motional Stark Effect (MSE). During the course of this work it was discovered that the MSE diagnostic suffers from interference from polarised background light. A prototype mitigation system was successfully tested. Also, non-linearities in the diagnostic's optical relay system were found and a calibration scheme devised to take them into account. Both the conventional approach of AT

  14. Inter-ELM evolution of the edge current density profile on the ASDEX Upgrade tokamak

    International Nuclear Information System (INIS)

    Dunne, Michael G.

    2014-01-01

    The sudden decrease of plasma stored energy and subsequent power deposition on the first wall of a tokamak device due to edge localised modes (ELMs) is potentially detrimental to the success of a future fusion reactor. Understanding and control of ELMs is critical for the longevity of these devices and also to maximise their performance. The commonly accepted picture of ELMs posits a critical pressure gradient and current density in the plasma edge, above which coupled magnetohydrodynamic (MHD) peeling-ballooning modes are driven unstable. Much analysis has been presented in recent years on the spatial and temporal evolution of the edge pressure gradient. However, the edge current density has typically been overlooked due to the difficulties in measuring this quantity. In this thesis, a novel method of current density recovery is presented, using the equilibrium solver CLISTE to reconstruct a high resolution equilibrium utilising both external magnetic and internal edge kinetic data measured on the ASDEX Upgrade (AUG) tokamak. The evolution of the edge current density relative to an ELM crash is presented, showing that a resistive delay in the buildup of the current density is unlikely. An uncertainty analysis shows that the edge current density can be determined with an accuracy consistent with that of the kinetic data used. A comparison with neoclassical theory demonstrates excellent agreement between the current density determined by CLISTE and the calculated profiles. Three ELM mitigation regimes are investigated: Type-II ELMs, ELMs suppressed by external magnetic perturbations (MPs), and Nitrogen seeded ELMs. In the first two cases, the current density is found to decrease as mitigation onsets, indicating a more ballooning-like plasma behaviour. In the latter case, the flux surface averaged current density can decrease while the local current density increases, thus providing a mechanism to suppress both the peeling and ballooning modes.

  15. Monitoring millimeter wave stray radiation during ECRH operation at ASDEX Upgrade

    Science.gov (United States)

    Schubert, M.; Honecker, F.; Monaco, F.; Schmid-Lorch, D.; Schütz, H.; Stober, J.; Wagner, D.

    2012-09-01

    Due to imperfection of the single path absorption, ECRH at ASDEX Upgrade (AUG) is always accompanied by stray radiation in the vacuum vessel. New ECRH scenarios with O2 and X3 heating schemes extend the operational space, but they have also the potential to increase the level of stray radiation. There are hazards for invessel components. Damage on electric cables has already been encountered. It is therefore necessary to monitor and control the ECRH with respect to the stray radiation level. At AUG a system of Sniffer antennas equipped with microwave detection diodes is installed. The system is part of the ECRH interlock circuit. We notice, however, that during plasma operation the variations of the Sniffer antenna signal are very large. In laboratory measurements we see variations of up to 20 dB in the directional sensitivity and we conclude that an interference pattern is formed inside the copper sphere of the antenna. When ECRH is in plasma operation at AUG, the plasma is acting as a phase and mode mixer for the millimeter waves and thus the interference pattern inside the sphere changes with the characteristic time of the plasma dynamics. In order to overcome the difficulty of a calibrated measurement of the average stray radiation level, we installed bolometer and pyroelectric detectors, which intrinsically average over interference structures due to their large active area. The bolometer provides a robust calibration but with moderate temporal resolution. The pyroelectric detector provides high sensitivity and a good temporal resolution, but it raises issues of possible signal drifts in long pulses.

  16. Monitoring millimeter wave stray radiation during ECRH operation at ASDEX Upgrade

    Directory of Open Access Journals (Sweden)

    Wagner D.

    2012-09-01

    Full Text Available Due to imperfection of the single path absorption, ECRH at ASDEX Upgrade (AUG is always accompanied by stray radiation in the vacuum vessel. New ECRH scenarios with O2 and X3 heating schemes extend the operational space, but they have also the potential to increase the level of stray radiation. There are hazards for invessel components. Damage on electric cables has already been encountered. It is therefore necessary to monitor and control the ECRH with respect to the stray radiation level. At AUG a system of Sniffer antennas equipped with microwave detection diodes is installed. The system is part of the ECRH interlock circuit. We notice, however, that during plasma operation the variations of the Sniffer antenna signal are very large. In laboratory measurements we see variations of up to 20 dB in the directional sensitivity and we conclude that an interference pattern is formed inside the copper sphere of the antenna. When ECRH is in plasma operation at AUG, the plasma is acting as a phase and mode mixer for the millimeter waves and thus the interference pattern inside the sphere changes with the characteristic time of the plasma dynamics. In order to overcome the difficulty of a calibrated measurement of the average stray radiation level, we installed bolometer and pyroelectric detectors, which intrinsically average over interference structures due to their large active area. The bolometer provides a robust calibration but with moderate temporal resolution. The pyroelectric detector provides high sensitivity and a good temporal resolution, but it raises issues of possible signal drifts in long pulses.

  17. Collection strategy, inner morphology, and size distribution of dust particles in ASDEX Upgrade

    Science.gov (United States)

    Balden, M.; Endstrasser, N.; Humrickhouse, P. W.; Rohde, V.; Rasinski, M.; von Toussaint, U.; Elgeti, S.; Neu, R.; the ASDEX Upgrade Team

    2014-07-01

    The dust collection and analysis strategy in ASDEX Upgrade (AUG) is described. During five consecutive operation campaigns (2007-2011), Si collectors were installed, which were supported by filtered vacuum sampling and collection with adhesive tapes in 2009. The outer and inner morphology (e.g. shape) and elemental composition of the collected particles were analysed by scanning electron microscopy. The majority of the ˜50 000 analysed particles on the Si collectors of campaign 2009 contain tungsten—the plasma-facing material in AUG—and show basically two different types of outer appearance: spheroids and irregularly shaped particles. By far most of the W-dominated spheroids consist of a solid W core, i.e. solidified W droplets. A part of these particles is coated with a low-Z material; a process that seems to happen presumably in the far scrape-off layer plasma. In addition, some conglomerates of B, C and W appear as spherical particles after their contact with plasma. By far most of the particles classified as B-, C- and W-dominated irregularly shaped particles consist of the same conglomerate with varying fraction of embedded W in the B-C matrix and some porosity, which can exceed 50%. The fragile structures of many conglomerates confirm the absence of intensive plasma contact. Both the ablation and mobilization of conglomerate material and the production of W droplets are proposed to be triggered by arcing. The size distribution of each dust particle class is best described by a log-normal distribution allowing an extrapolation of the dust volume and surface area. The maximum in this distribution is observed above the resolution limit of 0.28 µm only for the W-dominated spheroids, at around 1 µm. The amount of W-containing dust is extrapolated to be less than 300 mg on the horizontal areas of AUG.

  18. Collection strategy, inner morphology, and size distribution of dust particles in ASDEX Upgrade

    International Nuclear Information System (INIS)

    Balden, M.; Endstrasser, N.; Rohde, V.; Rasinski, M.; Von Toussaint, U.; Elgeti, S.; Neu, R.; Humrickhouse, P.W.

    2014-01-01

    The dust collection and analysis strategy in ASDEX Upgrade (AUG) is described. During five consecutive operation campaigns (2007–2011), Si collectors were installed, which were supported by filtered vacuum sampling and collection with adhesive tapes in 2009. The outer and inner morphology (e.g. shape) and elemental composition of the collected particles were analysed by scanning electron microscopy. The majority of the ∼50 000 analysed particles on the Si collectors of campaign 2009 contain tungsten—the plasma-facing material in AUG—and show basically two different types of outer appearance: spheroids and irregularly shaped particles. By far most of the W-dominated spheroids consist of a solid W core, i.e. solidified W droplets. A part of these particles is coated with a low-Z material; a process that seems to happen presumably in the far scrape-off layer plasma. In addition, some conglomerates of B, C and W appear as spherical particles after their contact with plasma. By far most of the particles classified as B-, C- and W-dominated irregularly shaped particles consist of the same conglomerate with varying fraction of embedded W in the B–C matrix and some porosity, which can exceed 50%. The fragile structures of many conglomerates confirm the absence of intensive plasma contact. Both the ablation and mobilization of conglomerate material and the production of W droplets are proposed to be triggered by arcing. The size distribution of each dust particle class is best described by a log-normal distribution allowing an extrapolation of the dust volume and surface area. The maximum in this distribution is observed above the resolution limit of 0.28 µm only for the W-dominated spheroids, at around 1 µm. The amount of W-containing dust is extrapolated to be less than 300 mg on the horizontal areas of AUG. (paper)

  19. Experimental investigations of turbulent temperature fluctuations and phase angles in ASDEX Upgrade

    Science.gov (United States)

    Freethy, Simon

    2017-10-01

    A complete experimental understanding of the turbulent fluctuations in tokamak plasmas is essential for providing confidence in the extrapolation of heat transport models to future experimental devices and reactors. Guided by ``predict first'' nonlinear gyrokinetic simulations with the GENE code, two new turbulence diagnostics were designed and have been installed on ASDEX Upgrade (AUG) to probe the fundamentals of ion-scale turbulent electron heat transport. The first, a 30-channel correlation ECE (CECE) radiometer, measures radial profiles (0.5 a levels are in the range 0.3 - 0.8%. The second is formed by the addition of a reflectometer on the same line of sight to enable measurements of the phase angle between turbulent density and temperature fluctuations. Design predictions are followed by a more traditional ``post-diction'' validation study with GENE. Using a cutting edge synthetic diagnostic GENE shows a factor 1.6 - 2 over-prediction of the fluctuation amplitude, while matching both ion and electron heat fluxes within experimental error. Detailed sensitivity scans are underway to understand the robustness of this disagreement and a detailed assessment of the experimental errors has been carried out. The discrepancy opens questions about the role of multi-scale turbulence physics, but also indicates the need for the comparison of more experimental turbulence properties to have a more complete validation hierarchy. In an effort to understand the discrepancy, predictions of the nT-phase and the radial correlation length have been made along with an assessment of their sensitivity to experimental errors. Comparison to experimental measurements will be discussed. This work is supported in part by the US DOE under Grants DE-SC0006419 and DE-SC0017381. This work has also received funding from the European Union's Horizon 2020 research and innovation programme under Grant agreement number 633053.

  20. ECRH on ASDEX Upgrade - System Status, Feed-Back Control, Plasma Physics Results -

    Directory of Open Access Journals (Sweden)

    Flamm J.

    2012-09-01

    Full Text Available The ASDEX Upgrade (AUG ECRH system now delivers a total of 3.9 MW to the plasma at 140 GHz. Three new units are capable of 2-frequency operation and may heat the plasma alternatively with 2.1 MW at 105 GHz. The system is routinely used with X2, O2, and X3 schemes. For Bt = 3.2 T also an ITER-like O1-scheme can be run using 105 GHz. The new launchers are capable of fast poloidal movements necessary for real-time control of the location of power deposition. Here real-time control of NTMs is summarized, which requires a fast analysis of massive data streams (ECE and Mirnov correlation and extensive calculations (equilibria, ray-tracing. These were implemented at AUG using a modular concept of standardized real-time diagnostics. The new realtime capabilities have also been used during O2 heating to keep the first reflection of the non-absorbed beam fraction on the holographic reflector tile which ensures a well defined second pass of the beam through the central plasma. Sensors for the beam position are fast thermocouples at the edge of the reflector tile. The enhanced ECRH power was used for several physics studies related to the unique feature of pure electron heating without fueling and without momentum input. As an example the effect of the variation of the heating mix in moderately heated H-modes is demonstrated using the three available heating systems, i.e. ECRH, ICRH and NBI. Keeping the total input power constant, strong effects are seen on the rotation, but none on the pedestal parameters. Also global quantities as the stored energy are hardly modified. Still it is found that the central ion temperature drops as the ECRH fraction exceeds a certain threshold.

  1. Inter-ELM evolution of the edge current density profile on the ASDEX Upgrade tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Dunne, Michael G.

    2014-02-15

    The sudden decrease of plasma stored energy and subsequent power deposition on the first wall of a tokamak device due to edge localised modes (ELMs) is potentially detrimental to the success of a future fusion reactor. Understanding and control of ELMs is critical for the longevity of these devices and also to maximise their performance. The commonly accepted picture of ELMs posits a critical pressure gradient and current density in the plasma edge, above which coupled magnetohydrodynamic (MHD) peeling-ballooning modes are driven unstable. Much analysis has been presented in recent years on the spatial and temporal evolution of the edge pressure gradient. However, the edge current density has typically been overlooked due to the difficulties in measuring this quantity. In this thesis, a novel method of current density recovery is presented, using the equilibrium solver CLISTE to reconstruct a high resolution equilibrium utilising both external magnetic and internal edge kinetic data measured on the ASDEX Upgrade (AUG) tokamak. The evolution of the edge current density relative to an ELM crash is presented, showing that a resistive delay in the buildup of the current density is unlikely. An uncertainty analysis shows that the edge current density can be determined with an accuracy consistent with that of the kinetic data used. A comparison with neoclassical theory demonstrates excellent agreement between the current density determined by CLISTE and the calculated profiles. Three ELM mitigation regimes are investigated: Type-II ELMs, ELMs suppressed by external magnetic perturbations (MPs), and Nitrogen seeded ELMs. In the first two cases, the current density is found to decrease as mitigation onsets, indicating a more ballooning-like plasma behaviour. In the latter case, the flux surface averaged current density can decrease while the local current density increases, thus providing a mechanism to suppress both the peeling and ballooning modes.

  2. Different ELM regimes at ASDEX upgrade and their linear stability analysis

    International Nuclear Information System (INIS)

    Burckhart, Andreas O.

    2013-01-01

    Edge localised modes (ELMs) are magnetohydrodynamic (MHD) instabilities that occur at the edge of magnetically confined fusion plasmas. They periodically expel particles and energy from the confined region. In addition to limiting the confinement, they cause high heat fluxes to the walls of the tokamak which may not be manageable in larger, next-generation devices. However, the exact nature of the instabilities that drive ELMs is still unknown. The most commonly invoked theory to explain the occurrence of ELMs is the peeling-ballooning model which posits a critical edge pressure gradient and current density. In this thesis, this model is tested against experimental data gathered at the ASDEX Upgrade (AUG) tokamak. For the first time, a broad selection of ELM scenarios is analysed with respect to ideal MHD stability using the same methodology. The comparison of experiment and theory is performed using a stability analysis chain, which consists of combining kinetic and magnetic measurements to generate self-consistent plasma equilibria with the Grad-Shafranov solver CLISTE, refining this equilibrium with the HELENA code, and, finally, determining its stability using ILSA, a linear MHD stability code. In theory the peeling ballooning model should apply to all type-I ELM scenarios. Therefore, the stability of several different type-I ELMy H-mode plasmas is analysed with respect to peeling ballooning modes. While some of them are consistent with the model, in others ELMs occur well below or above the ideal MHD stability limit. The standard type-I ELMy H-mode regime exhibits considerable variations with equilibria both well below and at the stability limit depending on the discharge. In addition, a nitrogen-seeded case in which the edge pressure gradient greatly exceeds the stability limit is identified. In another discharge, the edge pressure gradient and current density, which are on the threshold for marginal stability, relax when edge heating is applied. Contrary to

  3. Different ELM regimes at ASDEX upgrade and their linear stability analysis

    Energy Technology Data Exchange (ETDEWEB)

    Burckhart, Andreas O.

    2013-12-16

    Edge localised modes (ELMs) are magnetohydrodynamic (MHD) instabilities that occur at the edge of magnetically confined fusion plasmas. They periodically expel particles and energy from the confined region. In addition to limiting the confinement, they cause high heat fluxes to the walls of the tokamak which may not be manageable in larger, next-generation devices. However, the exact nature of the instabilities that drive ELMs is still unknown. The most commonly invoked theory to explain the occurrence of ELMs is the peeling-ballooning model which posits a critical edge pressure gradient and current density. In this thesis, this model is tested against experimental data gathered at the ASDEX Upgrade (AUG) tokamak. For the first time, a broad selection of ELM scenarios is analysed with respect to ideal MHD stability using the same methodology. The comparison of experiment and theory is performed using a stability analysis chain, which consists of combining kinetic and magnetic measurements to generate self-consistent plasma equilibria with the Grad-Shafranov solver CLISTE, refining this equilibrium with the HELENA code, and, finally, determining its stability using ILSA, a linear MHD stability code. In theory the peeling ballooning model should apply to all type-I ELM scenarios. Therefore, the stability of several different type-I ELMy H-mode plasmas is analysed with respect to peeling ballooning modes. While some of them are consistent with the model, in others ELMs occur well below or above the ideal MHD stability limit. The standard type-I ELMy H-mode regime exhibits considerable variations with equilibria both well below and at the stability limit depending on the discharge. In addition, a nitrogen-seeded case in which the edge pressure gradient greatly exceeds the stability limit is identified. In another discharge, the edge pressure gradient and current density, which are on the threshold for marginal stability, relax when edge heating is applied. Contrary to

  4. Characterization of type-I ELM induced filaments in the far scrape-off layer of ASDEX upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Schmid, Andreas

    2008-03-18

    This thesis focuses on the characterization of filaments and their propagation in the ASDEX Upgrade tokamak. The aim is to provide experimental measurements for understanding the filament formation process and their temporal evolution, and to provide a comprehensive database for an extrapolation to future fusion devices. For this purpose, a new magnetically driven probe for filament measurements has been developed and installed in ASDEX Upgrade. The probe carries several Langmuir probes and a magnetic coil in between. The Langmuir probes allow for measurements of the radial and poloidal/toroidal propagation of filaments as well as for measurements of filament size, density, and their radial (or temporal) evolution. The magnetic coil on the filament probe allows for measurements of currents in the filaments. A set of 7 coils, measuring 3 field components at different positions along the filament, has been used to measure the magnetic signature during an ELM. The aim was, on the one hand, to study which role filaments play for the magnetic structure, and on the other hand if the parallel currents predicted by the sheath damped model could be verified. Filament temperatures have been derived and the corresponding heat transport mechanisms have been studied. (orig.)

  5. A forward model for the helium plume effect and the interpretation of helium charge exchange measurements at ASDEX Upgrade

    Science.gov (United States)

    Kappatou, A.; McDermott, R. M.; Pütterich, T.; Dux, R.; Geiger, B.; Jaspers, R. J. E.; Donné, A. J. H.; Viezzer, E.; Cavedon, M.; the ASDEX Upgrade Team

    2018-05-01

    The analysis of the charge exchange measurements of helium is hindered by an additional emission contributing to the spectra, the helium ‘plume’ emission (Fonck et al 1984 Phys. Rev. A 29 3288), which complicates the interpretation of the measurements. The plume emission is indistinguishable from the active charge exchange signal when standard analysis of the spectra is applied and its intensity is of comparable magnitude for ASDEX Upgrade conditions, leading to a significant overestimation of the He2+ densities if not properly treated. Furthermore, the spectral line shape of the plume emission is non-Gaussian and leads to wrong ion temperature and flow measurements when not taken into account. A kinetic model for the helium plume emission has been developed for ASDEX Upgrade. The model is benchmarked against experimental measurements and is shown to capture the underlying physics mechanisms of the plume effect, as it can reproduce the experimental spectra and provides consistent values for the ion temperature, plasma rotation, and He2+ density.

  6. Characterization of type-I ELM induced filaments in the far scrape-off layer of ASDEX upgrade

    International Nuclear Information System (INIS)

    Schmid, Andreas

    2008-01-01

    This thesis focuses on the characterization of filaments and their propagation in the ASDEX Upgrade tokamak. The aim is to provide experimental measurements for understanding the filament formation process and their temporal evolution, and to provide a comprehensive database for an extrapolation to future fusion devices. For this purpose, a new magnetically driven probe for filament measurements has been developed and installed in ASDEX Upgrade. The probe carries several Langmuir probes and a magnetic coil in between. The Langmuir probes allow for measurements of the radial and poloidal/toroidal propagation of filaments as well as for measurements of filament size, density, and their radial (or temporal) evolution. The magnetic coil on the filament probe allows for measurements of currents in the filaments. A set of 7 coils, measuring 3 field components at different positions along the filament, has been used to measure the magnetic signature during an ELM. The aim was, on the one hand, to study which role filaments play for the magnetic structure, and on the other hand if the parallel currents predicted by the sheath damped model could be verified. Filament temperatures have been derived and the corresponding heat transport mechanisms have been studied. (orig.)

  7. Micro-NRA and micro-3HIXE with He-3 microbeam on samples exposed in ASDEX Upgrade and Pilot-PSI machines

    NARCIS (Netherlands)

    Kelemen, M.; Zaloznik, A.; Vavpetic, P.; Pecovnik, M.; Pelicon, P.; Hakola, A.; Lahtinen, A.; Karhunen, J.; Piip, K.; van der Meiden, H. J.; Paris, P.; Laan, M.; Krieger, K.; Oberkofler, M.; Markelj, S.; ASDEX Upgrade team,

    2017-01-01

    Micro nuclear reaction analysis (micro-NRA) exploiting the nuclear reaction D(He-3,p)He-4 was used for post-mortem analyses of special marker samples, exposed to deuterium plasma inside ASDEX Upgrade (AUG) tokamak and to the deuterium plasma jet in the Pilot-PSI linear plasma gun. Lateral

  8. Radial transport in the far scrape-off layer of ASDEX upgrade during L-mode and ELMy H-mode

    DEFF Research Database (Denmark)

    Ionita, C.; Naulin, Volker; Mehlmann, F.

    2013-01-01

    The radial turbulent particle flux and the Reynolds stress in the scrape-off layer (SOL) of ASDEX Upgrade were investigated for two limited L-mode (low confinement) and one ELMy H-mode (high confinement) discharge. A fast reciprocating probe was used with a probe head containing five Langmuir...

  9. Influence of RF heating and MHD instabilities on the fast-ion distribution in ASDEX upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Weiland, Markus

    2016-06-07

    Fast, supra-thermal ions provide a powerful mechanism to heat fusion plasmas. Through Coulomb collisions with the thermal bulk plasma, they slow down and transfer their energy to the plasma. In present-day devices, fast ions are generated by neutral beam injection (NBI) and ion cyclotron resonance heating (ICRH). In future fusion reactors, the dominant heating source, which allows the ignition of a burning plasma, will be fast a-particles resulting from fusion reactions. In addition to plasma heating, fast ions can be utilized to drive plasma currents and rotation. It is therefore crucial for the success of future fusion devices (such as ITER and DEMO) to understand the physics of fast ions and ensure their safe confinement. This thesis focuses both on modeling and experimental aspects. A model to calculate the NBI fast-ion distribution rapidly has been developed. It is based on a combination of existing codes and analytic solutions. Due to the comparably low numerical effort, it can be used to calculate the fast-ion distribution in a large set of discharges, which is used to e.g. improve plasma equilibrium reconstructions. Experimentally, the physics of fast ions is investigated at the tokamak ASDEX Upgrade, using a FIDA (Fast-Ion D-Alpha) spectroscopy diagnostic. This diagnostic technique is based on charge-exchange reactions, that convert the ions into neutral atoms (keeping their momenta). The light emission from these neutral atoms can be collected by optics in the machine and analyzed with spectrometers. Here, the fast-ion contribution can be identified due to large Doppler shifts, and the shape of the spectrum yields information about the velocity distribution. The Doppler shift is given by a projection of the ion velocity vector onto the line of sight, such that observation from different viewing angles is needed to cover the entire velocity space. Therefore, the FIDA diagnostic has been upgraded from three viewing arrays to five, and the spectrometer has

  10. Influence of RF heating and MHD instabilities on the fast-ion distribution in ASDEX upgrade

    International Nuclear Information System (INIS)

    Weiland, Markus

    2016-01-01

    Fast, supra-thermal ions provide a powerful mechanism to heat fusion plasmas. Through Coulomb collisions with the thermal bulk plasma, they slow down and transfer their energy to the plasma. In present-day devices, fast ions are generated by neutral beam injection (NBI) and ion cyclotron resonance heating (ICRH). In future fusion reactors, the dominant heating source, which allows the ignition of a burning plasma, will be fast a-particles resulting from fusion reactions. In addition to plasma heating, fast ions can be utilized to drive plasma currents and rotation. It is therefore crucial for the success of future fusion devices (such as ITER and DEMO) to understand the physics of fast ions and ensure their safe confinement. This thesis focuses both on modeling and experimental aspects. A model to calculate the NBI fast-ion distribution rapidly has been developed. It is based on a combination of existing codes and analytic solutions. Due to the comparably low numerical effort, it can be used to calculate the fast-ion distribution in a large set of discharges, which is used to e.g. improve plasma equilibrium reconstructions. Experimentally, the physics of fast ions is investigated at the tokamak ASDEX Upgrade, using a FIDA (Fast-Ion D-Alpha) spectroscopy diagnostic. This diagnostic technique is based on charge-exchange reactions, that convert the ions into neutral atoms (keeping their momenta). The light emission from these neutral atoms can be collected by optics in the machine and analyzed with spectrometers. Here, the fast-ion contribution can be identified due to large Doppler shifts, and the shape of the spectrum yields information about the velocity distribution. The Doppler shift is given by a projection of the ion velocity vector onto the line of sight, such that observation from different viewing angles is needed to cover the entire velocity space. Therefore, the FIDA diagnostic has been upgraded from three viewing arrays to five, and the spectrometer has

  11. Divertor power and particle fluxes between and during type-I ELMs in the ASDEX Upgrade

    Science.gov (United States)

    Kallenbach, A.; Dux, R.; Eich, T.; Fischer, R.; Giannone, L.; Harhausen, J.; Herrmann, A.; Müller, H. W.; Pautasso, G.; Wischmeier, M.; ASDEX Upgrade Team

    2008-08-01

    Particle, electric charge and power fluxes for type-I ELMy H-modes are measured in the divertor of the ASDEX Upgrade tokamak by triple Langmuir probes, shunts, infrared (IR) thermography and spectroscopy. The discharges are in the medium to high density range, resulting in predominantly convective edge localized modes (ELMs) with moderate fractional stored energy losses of 2% or below. Time resolved data over ELM cycles are obtained by coherent averaging of typically one hundred similar ELMs, spatial profiles from the flush-mounted Langmuir probes are obtained by strike point sweeps. The application of simple physics models is used to compare different diagnostics and to make consistency checks, e.g. the standard sheath model applied to the Langmuir probes yields power fluxes which are compared with the thermographic measurements. In between ELMs, Langmuir probe and thermography power loads appear consistent in the outer divertor, taking into account additional load due to radiation and charge exchange neutrals measured by thermography. The inner divertor is completely detached and no significant power flow by charged particles is measured. During ELMs, quite similar power flux profiles are found in the outer divertor by thermography and probes, albeit larger uncertainties in Langmuir probe evaluation during ELMs have to be taken into account. In the inner divertor, ELM power fluxes from thermography are a factor 10 larger than those derived from probes using the standard sheath model. This deviation is too large to be caused by deficiencies of probe analysis. The total ELM energy deposition from IR is about a factor 2 higher in the inner divertor compared with the outer divertor. Spectroscopic measurements suggest a quite moderate contribution of radiation to the target power load. Shunt measurements reveal a significant positive charge flow into the inner target during ELMs. The net number of elementary charges correlates well with the total core particle loss

  12. Management of complex data flows in the ASDEX Upgrade plasma control system

    Energy Technology Data Exchange (ETDEWEB)

    Treutterer, Wolfgang, E-mail: Wolfgang.Treutterer@ipp.mpg.de [Max-Planck Institut fuer Plasmaphysik, EURATOM Association, Garching (Germany); Neu, Gregor; Raupp, Gerhard; Zasche, Dieter; Zehetbauer, Thomas [Max-Planck Institut fuer Plasmaphysik, EURATOM Association, Garching (Germany); Cole, Richard; Lueddecke, Klaus [Unlimited Computer Systems, Iffeldorf (Germany)

    2012-12-15

    Highlights: Black-Right-Pointing-Pointer Control system architectures with data-driven workflows are efficient, flexible and maintainable. Black-Right-Pointing-Pointer Signal groups provide coherence of interrelated signals and increase the efficiency of process synchronisation. Black-Right-Pointing-Pointer Sample tags indicating sample quality form the fundament of a local event handling strategy. Black-Right-Pointing-Pointer A self-organising workflow benefits from sample tags consisting of time stamp and stream activity. - Abstract: Establishing adequate technical and physical boundary conditions for a sustained nuclear fusion reaction is a challenging task. Phased feedback control and monitoring for heating, fuelling and magnetic shaping is mandatory, especially for fusion devices aiming at high performance plasmas. Technical and physical interrelations require close collaboration of many components in sequential as well as in parallel processing flows. Moreover, handling of asynchronous, off-normal events has become a key element of modern plasma performance optimisation and machine protection recipes. The manifoldness of plasma states and events, the variety of plant system operation states and the diversity in diagnostic data sampling rates can hardly be mastered with a rigid control scheme. Rather, an adaptive system topology in combination with sophisticated synchronisation and process scheduling mechanisms is suited for such an environment. Moreover, the system is subject to real-time control constraints: response times must be deterministic and adequately short. Therefore, the experimental tokamak device ASDEX Upgrade employs a discharge control system DCS, whose core has been designed to meet these requirements. In the paper we will compare the scheduling schemes for the parallelised realisation of a control workflow and show the advantage of a data-driven workflow over a managed workflow. The data-driven workflow as used in DCS is based on signals

  13. Management of complex data flows in the ASDEX Upgrade plasma control system

    International Nuclear Information System (INIS)

    Treutterer, Wolfgang; Neu, Gregor; Raupp, Gerhard; Zasche, Dieter; Zehetbauer, Thomas; Cole, Richard; Lüddecke, Klaus

    2012-01-01

    Highlights: ► Control system architectures with data-driven workflows are efficient, flexible and maintainable. ► Signal groups provide coherence of interrelated signals and increase the efficiency of process synchronisation. ► Sample tags indicating sample quality form the fundament of a local event handling strategy. ► A self-organising workflow benefits from sample tags consisting of time stamp and stream activity. - Abstract: Establishing adequate technical and physical boundary conditions for a sustained nuclear fusion reaction is a challenging task. Phased feedback control and monitoring for heating, fuelling and magnetic shaping is mandatory, especially for fusion devices aiming at high performance plasmas. Technical and physical interrelations require close collaboration of many components in sequential as well as in parallel processing flows. Moreover, handling of asynchronous, off-normal events has become a key element of modern plasma performance optimisation and machine protection recipes. The manifoldness of plasma states and events, the variety of plant system operation states and the diversity in diagnostic data sampling rates can hardly be mastered with a rigid control scheme. Rather, an adaptive system topology in combination with sophisticated synchronisation and process scheduling mechanisms is suited for such an environment. Moreover, the system is subject to real-time control constraints: response times must be deterministic and adequately short. Therefore, the experimental tokamak device ASDEX Upgrade employs a discharge control system DCS, whose core has been designed to meet these requirements. In the paper we will compare the scheduling schemes for the parallelised realisation of a control workflow and show the advantage of a data-driven workflow over a managed workflow. The data-driven workflow as used in DCS is based on signals connecting process outputs and inputs. These are implemented as real-time streams of data samples

  14. Damping System for Torsional Resonances in Generator Shafts Using a Feedback Controlled Buffer Storage of Magnetic Energy at ASDEX Upgrade

    International Nuclear Information System (INIS)

    Kaesemann, C.-P.; Huart, M.; Mueller, P.; Sigalov, A.

    2006-01-01

    The electrical power and energy for ASDEX Upgrade (AUG) is provided by three separate pulsed networks based on flywheel generators. Major damages at couplings of the shaft of the synchronous generator EZ4 (220 MVA / 600 MWs) were discovered during a routine check. The damage can only be explained by torsional resonances in the generator shaft which are excited by active power transients from the converter loads. For generator protection, torque sensors were installed near the coupling between the flywheel and the rotor. They cause an early termination of plasma experiments if a predefined torque level is exceeded. These terminations limited the achievable plasma current flattop time of AUG significantly. Since a low natural damping of the torsional resonances was identified as a major cause of the phenomena observed, novel feedback controlled DC circuits were developed providing electromagnetic damping for the generator shafts in case of excitation. Each damping circuit consists of a DC choke, acting as a buffer storage of magnetic energy, fed by a thyristor converter. The current reference for the converter is derived from the torque sensor signals. This enables the choke current to alternate with the measured natural frequency of the shaft assembly. Thus, with proper phasing, torsional resonances in generator shaft systems weighing more than 100 tons can be damped with little additional power. Since April 2003, the damping circuits have been routinely operated during all plasma experiments. Despite the low damping power used, torsional resonances could be reduced to a value that avoids a trip signal from the torque sensors. This paper describes the results from analysing, designing and testing of the feedback controlled buffer storage of magnetic energy, representing an effective and low cost solution for damping torsional resonances in electric power systems. It will present the layout, analyse the results of measurements obtained during commissioning and

  15. The enhanced pellet centrifuge launcher at ASDEX Upgrade: Advanced operation and application as technology test facility for ITER and DEMO

    Energy Technology Data Exchange (ETDEWEB)

    Ploeckl, B., E-mail: bernhard.ploeckl@ipp.mpg.de [Max Planck Institute for Plasma Physics, EURATOM Association, Boltzmannstr. 2, 85748 Garching (Germany); Day, Chr. [Karlsruhe Institute of Technology (KIT), 76021 Karlsruhe (Germany); Lamalle, Ph. [ITER Organization, Route de Vinon sur Verdon, CS 90046, 13067 Saint-Paul-lez-Durance (France); Lang, P.T.; Rohde, V.; Viezzer, E. [Max Planck Institute for Plasma Physics, EURATOM Association, Boltzmannstr. 2, 85748 Garching (Germany)

    2015-10-15

    The pellet centrifuge at ASDEX Upgrade has served for more than 20 years as a powerful tool for plasma control. Its recently enhanced control system provides more thorough control over parameters and a detailed view of all measured values. A study has recently been initiated on the conceptual design of an optimized DEMO core particle fuelling system. For this approach, first technical tests aimed on an optimized pellet transfer with respect to the preparation of the solid fuel and the transfer systems have been performed. An investigation of the temperature dependence of transfer efficiency (mass loss due to erosion and broken pellets) has revealed a weak dependence. For ITER, in which it is intended to operate a heating scheme with ICRF minority heating of He-3, test injections are performed using D{sub 2}-pellets as carriers for He-4. Admixing of N{sub 2} was investigated as well.

  16. Experimental investigation of heat transport and divertor loads of fusion plasmas in all metal ASDEX upgrade and JET

    International Nuclear Information System (INIS)

    Sieglin, Bernhard A.

    2014-01-01

    This work presents divertor heat load studies conducted at two of the largest tokamaks currently in operation, ASDEX Upgrade and the Joint European Torus (JET). A commonly agreed empirical scaling for the power fall-off length in H-mode obtained in carbon devices is validated in JET with the ILW. Bohm and Gyro-Bohm like models are identified as possible candidates describing the divertor broadening. Quantities for the assessment of the thermal load induced by transient heat loads are defined. JET with the ILW exhibits an on average longer ELM duration as compared to the carbon wall. For identical pedestal conditions the ELM durations in both cases are found to be the same within error bars. The energy fluency is found to depend mainly on the pedestal pressure with a weak dependence on the relative loss in stored energy. This is noteworthy since the current extrapolation to ITER assumes a linear dependence on the relative ELM size.

  17. Direct measurement of the plasma potential in the edge of ASDEX Upgrade using a self emitting probe

    International Nuclear Information System (INIS)

    Rohde, V.; Laux, M.; Bachmann, P.; Herrmann, A.; Weinlich, M.

    1997-01-01

    In this paper we present first measurements of the plasma potential close to the separatrix in ASDEX Upgrade using a self emitting tip. The probe was inserted into the edge plasma of AUG using the midplane manipulator. Assuming Maxwellian plasmas, the observations agree with the predicted voltage drop in the plasma sheath, V pl ps -V fl =2.5T e , where V pl ps is the plasma potential at the presheath boundary and V fl the floating potential. Applying this technique a rapid change of the plasma potential was observed close to the separatrix during Ohmic discharges. From the gradient we derive a radial electric field E r of about -5 kV/m close to separatrix. Further out the field strength changes sign and we find up to +7 kV/m in the SOL. (orig.)

  18. A fast framing camera system for observation of acceleration and ablation of cryogenic hydrogen pellet in ASDEX Upgrade plasmas

    International Nuclear Information System (INIS)

    Kocsis, G.; Kalvin, S.; Veres, G.; Cierpka, P.; Lang, P.T.; Neuhauser, J.; Wittman, C.; ASDEX Upgrade Team

    2004-01-01

    An observation system using fast digital cameras was developed to measure a cryogenic hydrogen pellet's cloud structure, trajectory, and velocity changes during its ablation in ASDEX Upgrade plasmas. In this article the system, the applied numerical methods, and the results are presented. The three-dimensional pellet trajectory and velocity components were reconstructed from images of observations from two different directions. Pellet acceleration both in the radial and toroidal directions was detected. The pellet cloud distribution was measured with high spatio-temporal resolution. The cloud surrounding the pellet was found to be elongated along the magnetic field lines. Its typical size is 5-7 cm along the field lines and 2 cm in the perpendicular directions. A cloud extension in the poloidal direction was also observed which may be related to the drift of the detached part of the cloud

  19. Progress in the prediction of disruptions in ASDEX-Upgrade via neural and fuzzy-neural techniques

    International Nuclear Information System (INIS)

    Versaci, M.; Morabito, F.C.; Tichmann, C.; Pautasso, G.

    2001-01-01

    The paper addresses the problem of predicting the onset of a disruption on the basis of some known precursors possibly announcing the event. The availability in real time of a large set of diagnostic signals allows us to collectively interpret the data in order to decide whether we are near a disruption or during a normal operation scenario. As a relevant experimental example, a database of disruptive discharges in ASDEX-Upgrade has been analysed in this work. Both Neural Networks (NN's) and Fuzzy Inference Systems (FIS) have been investigated as suitable tools to cope with the prediction problem. The experimental database has been exploited aiming to gain information about the mechanisms which drive the plasma column to a disruption. The proposed processor will operate by implementing a classification of the shot type, and outputting a real number that indicates the time left before the disruption will effectively take place (ttd). (author)

  20. Characterisation of the ELM synchronized H-mode edge pedestal in ASDEX upgrade and DIII-D

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, Philip A.; Wolfrum, Elisabeth; Guenter, Sibylle; Kurzan, Bernd; Zohm, Hartmut [Max Planck Institut fuer Plasmaphysik, EURATOM Association, Garching (Germany); Groebner, Rich; Osborne, Tom H.; Ferron, John; Snyder, Philip B. [General Atomics, San Diego, CA (United States); Dunne, Mike G. [Department of Physics, University College Cork, Association Euratom-DCU, Cork (Ireland); Collaboration: ASDEX Upgrade Team; DIII-D Team

    2011-07-01

    The results of a large database of edge pedestal data from type-I ELMy H-mode discharges from ASDEX Upgrade and DIII-D are presented. The data from high resolution edge diagnostics of both devices is analysed with the same analysis code in order to avoid systematic differences. Furthermore, sophisticated equilibrium reconstructions are used to asses uncertainties which arise during mapping from 2D real space coordinates to 1D flux coordinates. ELM synchronization allows the study of the pedestal structure at the ELM stability boundary. The pedestal is characterized by its top value, the gradient and the width. A large parameter range is covered by the two devices. Over this parameter range the profile shape of edge electron density differs from that of the temperature, irrespective of the device. However, the resulting electron pressure profile shape remains similar for all analysed H-Mode discharges.

  1. Gaseous electron multiplier-based soft x-ray plasma diagnostics development: Preliminary tests at ASDEX Upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Chernyshova, M., E-mail: maryna.chernyshova@ipplm.pl; Malinowski, K.; Czarski, T.; Kowalska-Strzęciwilk, E. [Institute of Plasma Physics and Laser Microfusion, Hery 23, 01-497 Warsaw (Poland); Wojeński, A.; Poźniak, K. T.; Kasprowicz, G.; Krawczyk, R.; Kolasiński, P.; Zabołotny, W.; Zienkiewicz, P. [Institute of Electronic Systems, Warsaw University of Technology, Nowowiejska 15/19, 00-665 Warsaw (Poland); Vezinet, D.; Herrmann, A. [Max Planck Institute for Plasma Physics, Boltzmannstr. 2, 85748 Garching (Germany); Mazon, D.; Jardin, A. [CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France)

    2016-11-15

    A Gaseous Electron Multiplier (GEM)-based detector is being developed for soft X-ray diagnostics on tokamaks. Its main goal is to facilitate transport studies of impurities like tungsten. Such studies are very relevant to ITER, where the excessive accumulation of impurities in the plasma core should be avoided. This contribution provides details of the preliminary tests at ASDEX Upgrade (AUG) with a focus on the most important aspects for detector operation in harsh radiation environment. It was shown that both spatially and spectrally resolved data could be collected, in a reasonable agreement with other AUG diagnostics. Contributions to the GEM signal include also hard X-rays, gammas, and neutrons. First simulations of the effect of high-energy photons have helped understanding these contributions.

  2. Impact of Te and ne on edge current density profiles in ELM mitigated regimes on ASDEX Upgrade

    Science.gov (United States)

    Dunne, M. G.; Rathgeber, S.; Burckhart, A.; Fischer, R.; Giannone, L.; McCarthy, P. J.; Schneider, P. A.; Wolfrum, E.; the ASDEX Upgrade Team

    2015-01-01

    ELM resolved edge current density profiles are reconstructed using the CLISTE equilibrium code. As input, highly spatially and temporally resolved edge electron temperature and density profiles are used in addition to data from the extensive set of external poloidal field measurements available at ASDEX Upgrade, flux loop difference measurements, and current measurements in the scrape-off layer. Both the local and flux surface averaged current density profiles are analysed for several ELM mitigation regimes. The focus throughout is on the impact of altered temperature and density profiles on the current density. In particular, many ELM mitigation regimes rely on operation at high density. Two reference plasmas with type-I ELMs are analysed, one with a deuterium gas puff and one without, in order to provide a reference for the behaviour in type-II ELMy regimes and high density ELM mitigation with external magnetic perturbations at ASDEX Upgrade. For type-II ELMs it is found that while a similar pedestal top pressure is sustained at the higher density, the temperature gradient decreases in the pedestal. This results in lower local and flux surface averaged current densities in these phases, which reduces the drive for the peeling mode. No significant differences between the current density measured in the type-I phase and ELM mitigated phase is seen when external perturbations are applied, though the pedestal top density was increased. Finally, ELMs during the nitrogen seeded phase of a high performance discharge are analysed and compared to ELMs in the reference phase. An increased pedestal pressure gradient, which is the source of confinement improvement in impurity seeded discharges, causes a local current density increase. However, the increased Zeff in the pedestal acts to reduce the flux surface averaged current density. This dichotomy, which is not observed in other mitigation regimes, could act to stabilize both the ballooning mode and the peeling mode at the

  3. Radial electric field studies in the plasma edge of ASDEX upgrade

    International Nuclear Information System (INIS)

    Viezzer, Eleonora

    2012-01-01

    In magnetically confined fusion plasmas, edge transport barriers (ETBs) are formed during the transition from a highly turbulent state (low confinement regime, L-mode) to a high energy confinement regime (H-mode) with reduced turbulence and transport. The performance of an H-mode fusion plasma is highly dependent on the strength of the ETB which extends typically over the outermost 5% of the confined plasma. The formation of the ETB is strongly connected to the existence of a sheared plasma flow perpendicular to the magnetic field caused by a local radial electric field E r . The gradients in E r and the accompanying E x B velocity shear play a fundamental role in edge turbulence suppression, transport barrier formation and the transition to H-mode. Thus, the interplay between macroscopic flows and transport at the plasma edge is of crucial importance to understanding plasma confinement and stability. The work presented in this thesis is based on charge exchange recombination spectroscopy (CXRS) measurements performed at the plasma edge of the ASDEX Upgrade (AUG) tokamak. During this thesis new high-resolution CXRS diagnostics were installed at the outboard and inboard miplane of AUG, which provide measurements of the temperature, density and flows of the observed species. From these measurements the radial electric field can be directly determined via the radial force balance equation. The new CXRS measurements, combined with the other edge diagnostics available at AUG, allow for an unprecedented, high-accuracy localization (2-3 mm) of the E r profile. The radial electric field has been derived from charge exchange spectra measured on different impurity species including He 2+ , B 5+ , C 6+ and Ne 10+ . The resulting E r profiles are found to be identical within the uncertainties regardless of the impurity species used, thus demonstrating the validity of the diagnostic technique. Inside the ETB the E r profile forms a deep, negative (i.e. directed towards the

  4. Latest investigations on fluctuations, ELM filaments and turbulent transport in the SOL of ASDEX Upgrade

    Czech Academy of Sciences Publication Activity Database

    Müller, H. W.; Adámek, Jiří; Cavazzana, R.; Conway, G.D.; Fuchs, C.; Gunn, J. P.; Herrmann, A.; Horáček, Jan; Ionita, C.; Kallenbach, A.; Kočan, M.; Maraschek, M.; Maszl, C.; Mehlmann, F.; Nold, B.; Peterka, M.; Rohde, V.; Schweinzer, J.; Schrittwieser, R.; Vianello, N.; Wolfrum, E.; Zuin, M.

    2011-01-01

    Roč. 51, č. 7 (2011), 073023-073023 ISSN 0029-5515 R&D Projects: GA AV ČR KJB100430901 Institutional research plan: CEZ:AV0Z20430508 Keywords : SOL * ASDEX * ELM * tokamak * ball- pen * H-mode Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 4.090, year: 2011 http://iopscience.iop.org/0029-5515/51/7/073023/pdf/0029-5515_51_7_073023.pdf

  5. Conceptual design of a Langmuir probe system for the tokamak ASDEX-UPGRADE

    International Nuclear Information System (INIS)

    Anastassiadis, A.; Tsingas, A.C.; Tsois, N.N.; Zoumbos, G.A.

    1985-05-01

    The conceptual design of a Langmuir probe system for the tokamak ASDEX-UPG is presented. This system is intended to carry out electrostatic measurements, in space and time, on the boundary layer plasma over the largest possible volume of the divertor plasma during discharges. Conducted by preset design requirements a fast probe system is proposed. During discharges signal measurements will be performed by means of a data-acquisition system and the motion will be controlled by a real-time computer. The desired information concerning plasma parameters and the motion of the probe system will be available to the diagnostician via a video display unit. (author)

  6. Validation of gyrokinetic simulations with measurements of electron temperature fluctuations and density-temperature phase angles on ASDEX Upgrade

    Science.gov (United States)

    Freethy, S. J.; Görler, T.; Creely, A. J.; Conway, G. D.; Denk, S. S.; Happel, T.; Koenen, C.; Hennequin, P.; White, A. E.; ASDEX Upgrade Team

    2018-05-01

    Measurements of turbulent electron temperature fluctuation amplitudes, δTe ⊥/Te , frequency spectra, and radial correlation lengths, Lr(Te ⊥) , have been performed at ASDEX Upgrade using a newly upgraded Correlation ECE diagnostic in the range of scales k⊥scale non-linear gyrokinetic turbulence simulations of the outer core (ρtor = 0.75) of a low density, electron heated L-mode plasma, performed using the gyrokinetic simulation code, GENE. The ion and electron temperature gradients were scanned within uncertainties. It is found that gyrokinetic simulations are able to match simultaneously the electron and ion heat flux at this radius within the experimental uncertainties. The simulations were performed based on a reference discharge for which δTe ⊥/Te measurements were available, and Lr(Te ⊥) and αnT were then predicted using synthetic diagnostics prior to measurements in a repeat discharge. While temperature fluctuation amplitudes are overestimated by >50% for all simulations within the sensitivity scans performed, good quantitative agreement is found for Lr(Te ⊥) and αnT. A validation metric is used to quantify the level of agreement of individual simulations with experimental measurements, and the best agreement is found close to the experimental gradient values.

  7. The spatial structure of type-I ELMs at the mid-plane in ASDEX Upgrade and a comparison with data from MAST

    International Nuclear Information System (INIS)

    Kirk, A; Eich, T; Herrmann, A; Muller, H W; Horton, L D; Counsell, G F; Price, M; Rohde, V; Bobkov, V; Kurzan, B; Neuhauser, J; Wilson, H

    2005-01-01

    The radial extent and spatial structure of type-I edge localized modes (ELMs) in ASDEX Upgrade are investigated using data from a mid-plane manipulator equipped with Langmuir probes and a fast visible imaging camera and are compared to data from MAST. Plasmas with a range of toroidal magnetic fields have been studied. The radial extent of the ELM efflux is found to be largest at the smaller toroidal magnetic field. A study of a series of shots on ASDEX Upgrade with different plasma edge to wall separation suggests that the closeness of the wall does not have a stabilizing effect on the radial extent of the ELM. The data from the mid-plane manipulator and from visible imaging are consistent with non-linear ballooning mode theory, which predicts that the ELM has a filament like structure. On both devices these structures have a poloidal extent of 5-10 cm and a typical toroidal mode number of ∼15 and are found to accelerate away from the plasma edge. The acceleration is ∼3 times larger on MAST than on ASDEX Upgrade

  8. Radial electric field studies in the plasma edge of ASDEX upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Viezzer, Eleonora

    2012-12-18

    In magnetically confined fusion plasmas, edge transport barriers (ETBs) are formed during the transition from a highly turbulent state (low confinement regime, L-mode) to a high energy confinement regime (H-mode) with reduced turbulence and transport. The performance of an H-mode fusion plasma is highly dependent on the strength of the ETB which extends typically over the outermost 5% of the confined plasma. The formation of the ETB is strongly connected to the existence of a sheared plasma flow perpendicular to the magnetic field caused by a local radial electric field E{sub r}. The gradients in E{sub r} and the accompanying E x B velocity shear play a fundamental role in edge turbulence suppression, transport barrier formation and the transition to H-mode. Thus, the interplay between macroscopic flows and transport at the plasma edge is of crucial importance to understanding plasma confinement and stability. The work presented in this thesis is based on charge exchange recombination spectroscopy (CXRS) measurements performed at the plasma edge of the ASDEX Upgrade (AUG) tokamak. During this thesis new high-resolution CXRS diagnostics were installed at the outboard and inboard miplane of AUG, which provide measurements of the temperature, density and flows of the observed species. From these measurements the radial electric field can be directly determined via the radial force balance equation. The new CXRS measurements, combined with the other edge diagnostics available at AUG, allow for an unprecedented, high-accuracy localization (2-3 mm) of the E{sub r} profile. The radial electric field has been derived from charge exchange spectra measured on different impurity species including He{sup 2+}, B{sup 5+}, C{sup 6+} and Ne{sup 10+}. The resulting E{sub r} profiles are found to be identical within the uncertainties regardless of the impurity species used, thus demonstrating the validity of the diagnostic technique. Inside the ETB the E{sub r} profile forms a deep

  9. Development and application of poloidal correlation reflectometry to study turbulent structures in the ASDEX Upgrade tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Prisiazhniuk, Dmitrii

    2017-06-05

    One of the key question of high temperature plasma confinement in a magnetic field is how plasma turbulence influences the radial transport of particles and energy. A better understanding of transport processes caused by turbulence would allow to improve the plasma confinement in fusion devices. To this end a deeper understanding of the mechanisms controlling the development, saturation and stabilization of turbulence is needed. From the experimental point of view a main challenge in these investigations is the measurement of plasma parameters on both small temporal (μs) and spatial (mm) scales. In this thesis a new microwave heterodyne poloidal correlation reflectometry diagnostic has been developed and installed at the ASDEX Upgrade tokamak to investigate the cross-correlation of turbulent density fluctuations. This diagnostic yields information on fundamental turbulence parameters such as the perpendicular propagation velocity v {sub perpendicular} {sub to}, the perpendicular correlation length l {sub perpendicular} {sub to} (characteristic size of the turbulent eddies) and the decorrelation time τ{sub d} (characteristic life time of the turbulent eddies) over a wide range of plasma densities. The inclination of the turbulent eddies α in the poloidal-toroidal plane spanned by the magnetic flux surfaces of a tokamak, being a measure of the magnetic field pitch angle, can also be obtained. The turbulence investigations were performed in low confinement mode (L-mode) plasmas for a range of plasma parameters. All measurements were interpreted taking into account the transfer function of reflectometry in the Born approximation. The results are compared with theoretical predictions and simulations. In the first part of this thesis the inclination and the propagation of turbulent structures are investigated. It is shown that eddies are nearly aligned to the magnetic field line and, therefore, the magnetic field pitch angle can be measured with a precision of about 1

  10. Path-oriented early reaction to approaching disruptions in ASDEX Upgrade and TCV in view of the future needs for ITER and DEMO

    Science.gov (United States)

    Maraschek, M.; Gude, A.; Igochine, V.; Zohm, H.; Alessi, E.; Bernert, M.; Cianfarani, C.; Coda, S.; Duval, B.; Esposito, B.; Fietz, S.; Fontana, M.; Galperti, C.; Giannone, L.; Goodman, T.; Granucci, G.; Marelli, L.; Novak, S.; Paccagnella, R.; Pautasso, G.; Piovesan, P.; Porte, L.; Potzel, S.; Rapson, C.; Reich, M.; Sauter, O.; Sheikh, U.; Sozzi, C.; Spizzo, G.; Stober, J.; Treutterer, W.; ZancaP; ASDEX Upgrade Team; TCV Team; the EUROfusion MST1 Team

    2018-01-01

    Routine reaction to approaching disruptions in tokamaks is currently largely limited to machine protection by mitigating an ongoing disruption, which remains a basic requirement for ITER and DEMO [1]. Nevertheless, a mitigated disruption still generates stress to the device. Additionally, in future fusion devices, high-performance discharge time itself will be very valuable. Instead of reacting only on generic features, occurring shortly before the disruption, the ultimate goal is to actively avoid approaching disruptions at an early stage, sustain the discharges whenever possible and restrict mitigated disruptions to major failures. Knowledge of the most relevant root causes and the corresponding chain of events leading to disruption, the disruption path, is a prerequisite. For each disruption path, physics-based sensors and adequate actuators must be defined and their limitations considered. Early reaction facilitates the efficiency of the actuators and enhances the probability of a full recovery. Thus, sensors that detect potential disruptions in time are to be identified. Once the entrance into a disruption path is detected, we propose a hierarchy of actions consisting of (I) recovery of the discharge to full performance or at least continuation with a less disruption-prone backup scenario, (II) complete avoidance of disruption to sustain the discharge or at least delay it for a controlled termination and, (III), only as last resort, a disruption mitigation. Based on the understanding of disruption paths, a hierarchical and path-specific handling strategy must be developed. Such schemes, testable in present devices, could serve as guidelines for ITER and DEMO operation. For some disruption paths, experiments have been performed at ASDEX Upgrade and TCV. Disruptions were provoked in TCV by impurity injection into ELMy H-mode discharges and in ASDEX Upgrade by forcing a density limit in H-mode discharges. The new approach proposed in this paper is discussed for

  11. Development of a flexible Doppler reflectometry system and its application to turbulence characterization in the ASDEX Upgrade tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Troester, Carolin Helma

    2008-04-15

    An essential challenge in present fusion plasma research is the study of plasma turbulence. The turbulence behavior is investigated experimentally on the ASDEX Upgrade tokamak using Doppler reflectometry, a diagnostic technique sensitive to density fluctuations at a specific wavenumber k {sub perpendicular} {sub to}. This microwave radar diagnostic utilizes localized Bragg backscattering of the launched beam (k{sub 0}) by the density fluctuations at the plasma cutoff layer. The incident angle {theta} selects the probed k {sub perpendicular} {sub to} via the Bragg condition k {sub perpendicular} {sub to} {approx} 2k{sub 0}sin{theta}. The measured Doppler shifted frequency spectrum allows the determination of the perpendicular plasma rotation velocity, u {sub perpendicular} {sub to} =v{sub E} {sub x} {sub B}+v{sub turb}, directly from the Doppler frequency shift(f{sub D} = u {sub perpendicular} {sub to} k {sub perpendicular} {sub to} /2{pi}), and the turbulence amplitude from the backscattered power level. This thesis work presents a survey of u {sub perpendicular} {sub to} radial profiles and k {sub perpendicular} {sub to} spectrum measurements for a variety of plasma conditions obtained by scanning the antenna tilt angle. This was achieved by extending the existing V-band Doppler reflectometry system (50 - 75 GHz) with a new W-band system (75 - 110 GHz), which was especially designed for measuring the k {sub perpendicular} {sub to} spectrum and additionally expands the radial coverage into the plasma core region. It consists of a remote steerable antenna with an adjustable line of sight allowing for dynamic wavenumber selection up to 25 cm {sup -1} and a reflectometer with a 'phase locked loop' stabilized transmitter allowing for the precise determination of the instrument response function. The proper system functionality was demonstrated by laboratory testing and benckmarking against the V-band system. The new profile measurements obtained show a

  12. High-speed lithium pellet injector commissioning in ASDEX Upgrade to investigate impact of Li in an all-metal wall tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Arredondo Parra, Rodrigo; Lang, Peter Thomas; Ploeckl, Bernhard [Max-Planck-Institut fuer Plasmaphysik, Garching (Germany); Cardella, Antonino [Technische Universitaet Muenchen, Garching (Germany); Fusion for Energy, Garching (Germany); Macian Juan, Rafael [Technische Universitaet Muenchen, Garching (Germany); Neu, Rudolf [Max-Planck-Institut fuer Plasmaphysik, Garching (Germany); Technische Universitaet Muenchen, Garching (Germany)

    2015-05-01

    Encouraging results with respect to plasma performance have been observed in several tokamak devices (TFTR, NSTX, etc) when injecting Lithium. Recently, a pedestal broadening resulting in an enhanced energy content during transient ELM-free H-mode phases was achieved in DIII-D. Experiments are planned at ASDEX Upgrade, aiming to investigate the impact of Li in an all-metal wall tokamak and to enhance the pedestal operational space. For this purpose, a Lithium pellet injector has been developed, capable of injecting pellets with a particle content up to 1.64 . 10{sup 20} atoms (1.89 mg) at a foreseen maximum repetition rate of 3 Hz. Free flight launch from the torus outboard side without a guiding tube is envisaged. A transfer efficiency exceeding 90 % was achieved in the test bed. Pellets will be accelerated in a gas gun; hence special care must be taken to avoid deleterious effects by the propellant gas pulse, this being the main plasma gas, leading to speeds ranging from 500 (m)/(s) to 800 (m)/(s). Additionally, a large expansion volume equipped with a cryopump is added in to the flight path. The injector is expected to commence operation by May 2015.

  13. Small ELM regimes with good confinement on JET and comparison to those on ASDEX Upgrade, Alcator C-mod, and JT-60U

    International Nuclear Information System (INIS)

    Stober, J.; Lomas, P.; Saibene, G.

    2005-01-01

    Since it is uncertain if ITER operation is compatible with type-I ELMs, the study of alternative H-mode pedestals is an urgent issue. This paper reports on experiments on JET aiming to find scenarios with small ELMs and good confinement, such as the type-II ELMs in ASDEX Upgrade, the enhanced D-alpha H-mode in Alcator C-mod or the grassy ELMs in JT-60U. The study includes shape variations, especially the closeness to a double-null configuration, variations of q 95 , density and beta poloidal. H-mode pedestals without type-I ELMs have been observed only at the lowest currents (≤ 1.2 MA), showing similarities to the observations in the devices mentioned above. These are discussed in detail on the basis of edge fluctuation analysis. For higher currents, only the mixed type-I/II scenario is observed. Although the increased inter-ELM transport reduces the type-I ELM frequency, a single type-I ELM is not significantly reduced in size. Obviously, these results do question the accessibility of such small ELM scenarios on ITER, except perhaps the high beta-poloidal scenario at higher q 95 , which could not be tested at higher currents at JET due to limitations in heating power. (author)

  14. Quantitative AMS depth profiling of the hydrogen isotopes collected in graphite divertor and wall tiles of the tokamak ASDEX-Upgrade

    International Nuclear Information System (INIS)

    Sun, G.Y.; Friedrich, M.; Groetzschel, R.; Buerger, W.; Behrisch, R.; Garcia-Rosales, C.

    1997-01-01

    The accelerator mass spectrometry (AMS) facility at the 3 MV Tandetron in Rossendorf has been applied for quantitative depth profiling of deuterium and tritium in samples cut from graphite protection tiles at the vessel walls of the fusion experiment ASDEX-Upgrade at the Max-Planck-Institut fuer Plasmaphysik in Garching. The tritium originates from D(d,p)T fusion reactions in the plasma and it is implanted in the vessel walls together with deuterium atoms and ions from the plasma. The T concentrations in the surface layers down to the analyzing depth of about 25 μm are in the range of 10 11 to 5 x 10 15 T-atoms/cm 3 corresponding to a tritium retention of 3 x 10 10 to 3.5 x 10 12 T-atoms/cm 2 . The much higher deuterium concentrations in the samples were simultaneously measured by calibrated conventional SIMS. In the surface layers down to the analyzing depth of about 25 μm the deuterium concentrations are between 3 x 10 18 and 8 x 10 21 atoms/cm 3 , corresponding to a deuterium retention of 2.5 x 10 16 to 2.5 x 10 18 atoms/cm 2 The estimated total amount of tritium in the vessel walls is of the same order of magnitude as the total number of neutrons produced in D(d,n) 3 He reactions. (orig.)

  15. MHD phenomena in advanced scenarios on ASDEX upgrade and the influence of localised electron heating and current drive

    International Nuclear Information System (INIS)

    Guenter, S.; Gude, A.; Hobirk, J.; Maraschek, M.; Peeters, A.G.; Pinches, S.D.; Schade, S.; Wolf, R.C.; Saarelma, S.

    2001-01-01

    MHD instabilities in advanced tokamak scenarios on the one hand are favourable as they can contribute to the stationarity of the current profiles and act as a trigger for the formation of internal transport barriers. In particular fishbone oscillations driven by fast particles arising from neutral beam injection (NBI) are shown to trigger internal transport barriers in low and reversed magnetic shear discharges. During the whistling down period of the fishbone oscillation the transport is reduced around the corresponding rational surface, leading to an increased pressure gradient. This behaviour is explained by the redistribution of the resonant fast particles resulting in a sheared plasma rotation due to the return current in the bulk plasma, which is equivalent to a radial electric field. On the other hand MHD instabilities limit the accessible operating regime. Ideal and resistive MHD modes such as double tearing modes, infernal modes and external kinks degrade the confinement or even lead to disruptions in ASDEX Upgrade reversed shear discharges. Localized electron cyclotron heating and current drive is shown to significantly affect the MHD stability of this type of discharges. (author)

  16. MHD phenomena in advanced scenarios on ASDEX Upgrade and the influence of localized electron heating and current drive

    International Nuclear Information System (INIS)

    Guenter, S.; Gude, A.; Hobirk, J.; Maraschek, M.; Schade, S.; Wolf, R.C.; Saarelma, S.

    2001-01-01

    On the one hand, MHD instabilities in advanced tokamak scenarios are favourable as they can contribute to the stationarity of the current profiles and act as a trigger for the formation of internal transport barriers (ITBs). In particular, fishbone oscillations driven by fast particles arising from NBI are shown to trigger ITBs in low and reversed magnetic shear discharges. During the whistling down period of the fishbone oscillation the transport is reduced around the corresponding rational surface, leading to an increased pressure gradient. This behaviour could be explained by the redistribution of the resonant fast particles resulting in a sheared plasma rotation due to the return current in the bulk plasma, which is equivalent to a radial electric field. On the other hand, MHD instabilities limit the accessible operating regime. Ideal and resistive MHD modes such as double tearing modes, infernal modes and external kinks degrade the confinement or even lead to disruptions in ASDEX Upgrade reversed shear discharges. Localized electron cyclotron heating and current drive are shown to significantly affect the MHD stability of this type of discharge. (author)

  17. Interpretation of the effects of electron cyclotron power absorption in pre-disruptive tokamak discharges in ASDEX Upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Nowak, S.; Lazzaro, E.; Granucci, G. [Associazione Euratom-CNR sulla Fusione, IFP-CNR, Via R. Cozzi 53, 20125 Milano (Italy); Esposito, B. [Associazione Euratom-CNR sulla Fusione, CR Frascati, C.P. 65, 00044 Frascati (Italy); Maraschek, M.; Zohm, H. [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, Boltzmannstr.2, 85748 Garching bei Munchen (Germany); Sauter, O.; Brunetti, D. [CRPP, Association Euratom-Confederation Suisse, EPFL, 1015 Lausanne (Switzerland); Collaboration: ASDEX Upgrade Team

    2012-09-15

    Tokamak disruptions are events of fatal collapse of the magnetohydrodynamic (MHD) confinement configuration, which cause a rapid loss of the plasma thermal energy and the impulsive release of magnetic energy and heat on the tokamak first wall components. The physics of the disruptions is very complex and non-linear, strictly associated with the dynamics of magnetic tearing perturbations. The crucial problem of the response to the effects of localized heat deposition and current driven by external (rf) sources to avoid or quench the MHD tearing instabilities has been investigated both experimentally and theoretically on the ASDEX Upgrade tokamak. The analysis of the conditions under which a disruption can be prevented by injection of electron cyclotron (EC) rf power, or, alternatively, may be caused by it, shows that the local EC heating can be more significant than EC current drive in ensuring neoclassical tearing modes (NTMs) stability, due to two main reasons: first, the drop of temperature associated with the island thermal short circuit tends to reduce the neoclassical character of the instability and to limit the EC current drive generation; second, the different effects on the mode evolution of both the location of the power deposition relative to the island separatrix and the island shape deformation lead to less strict requirements of precise power deposition focussing. A contribution to the validation of theoretical models of the events associated with NTM is given and can be used to develop concepts for their control, relevant also for ITER-like scenarios.

  18. Investigations on the edge kinetic data in regimes with type-I and mitigated ELMs at ASDEX Upgrade

    International Nuclear Information System (INIS)

    Rathgeber, S.K.; Barrera, L.; Birkenmeier, G.; Fischer, R.; Suttrop, W.

    2014-01-01

    The behaviour of profiles and gradients of electron density, temperature and pressure at the edge of ASDEX Upgrade was studied in regimes with type-I and small edge localized modes (ELMs) of discharges with and without applied magnetic perturbations (MPs). Estimation of the edge kinetic parameters was performed by means of integrated data analysis for joint reconstruction of electron density and temperature profiles via combination of data from different diagnostics. The MP fields for ELM mitigation were produced by 16 in-vessel coils allowing to execute this survey with large variations in poloidal spectrum and resonant component of the error field. With several dedicated discharges the effect of MPs on the edge kinetic data and ELMs was determined in dependence of heating power, gas puff and MP-coil configuration. Small ELMs are dominant—with and without MPs—in regimes with reduced pedestal top electron temperatures and flattened edge electron pressure gradients compared to type-I ELM phases. Furthermore, application of MPs opens an additional small ELM regime in the high temperature range at reduced electron pressure gradient. (paper)

  19. Velocity space resolved absolute measurement of fast ion losses induced by a tearing mode in the ASDEX Upgrade tokamak

    Science.gov (United States)

    Galdon-Quiroga, J.; Garcia-Munoz, M.; Sanchis-Sanchez, L.; Mantsinen, M.; Fietz, S.; Igochine, V.; Maraschek, M.; Rodriguez-Ramos, M.; Sieglin, B.; Snicker, A.; Tardini, G.; Vezinet, D.; Weiland, M.; Eriksson, L. G.; The ASDEX Upgrade Team; The EUROfusion MST1 Team

    2018-03-01

    Absolute flux of fast ion losses induced by tearing modes have been measured by means of fast ion loss detectors (FILD) for the first time in RF heated plasmas in the ASDEX Upgrade tokamak. Up to 30 MW m-2 of fast ion losses are measured by FILD at 5 cm from the separatrix, consistent with infra-red camera measurements, with energies in the range of 250-500 keV and pitch angles corresponding to large trapped orbits. A resonant interaction between the fast ions in the high energy tail of the ICRF distribution and a m/n  =  5/4 tearing mode leads to enhanced fast ion losses. Around 9.3 +/- 0.7 % of the fast ion losses are found to be coherent with the mode and scale linearly with its amplitude, indicating the convective nature of the transport mechanism. Simulations have been carried out to estimate the contribution of the prompt losses. A good agreement is found between the simulated and the measured velocity space of the losses. The velocity space resonances that may be responsible for the enhanced fast ion losses are identified.

  20. Scintillator based detector for fast-ion losses induced by magnetohydrodynamic instabilities in the ASDEX upgrade tokamak.

    Science.gov (United States)

    García-Muñoz, M; Fahrbach, H-U; Zohm, H

    2009-05-01

    A scintillator based detector for fast-ion losses has been designed and installed on the ASDEX upgrade (AUG) tokamak [A. Herrmann and O. Gruber, Fusion Sci. Technol. 44, 569 (2003)]. The detector resolves in time the energy and pitch angle of fast-ion losses induced by magnetohydrodynamics (MHD) fluctuations. The use of a novel scintillator material with a very short decay time and high quantum efficiency allows to identify the MHD fluctuations responsible for the ion losses through Fourier analysis. A Faraday cup (secondary scintillator plate) has been embedded behind the scintillator plate for an absolute calibration of the detector. The detector is mounted on a manipulator to vary its radial position with respect to the plasma. A thermocouple on the inner side of the graphite protection enables the safety search for the most adequate radial position. To align the scintillator light pattern with the light detectors a system composed by a lens and a vacuum-compatible halogen lamp has been allocated within the detector head. In this paper, the design of the scintillator probe, as well as the new technique used to analyze the data through spectrograms will be described. A last section is devoted to discuss the diagnosis prospects of this method for ITER [M. Shimada et al., Nucl. Fusion 47, S1 (2007)].

  1. Studies of tungsten erosion at the inner and outer main chamber wall of the ASDEX Upgrade tokamak

    Science.gov (United States)

    Tabasso, A.; Maier, H.; Roth, J.; Krieger, K.; ASDEX Upgrade Team

    2001-03-01

    A critical issue for the choice of main chamber first wall materials in future fusion devices such as ITER is the erosion rate due to bombardment by charge-exchange (CX) neutrals. Due to the relatively small flux density of impacting particles, respective measurements are only possible using long term samples (LTS) exposed for a full experimental campaign. In ASDEX Upgrade, CX erosion has been studied extensively for tungsten on the inner heat shield by placing four W coated tiles at different poloidal positions in one toroidal sector. During the same campaign, several LTS were placed at different poloidal and toroidal positions of the outer wall. 13C and Cu coated graphite probes were also used in order to test and compare W low and medium Z alternatives. The erosion results from the probes are compared with the calculated erosion [W. Eckstein, C. Garcia-Rosales, J. Roth, W. Ottenberger IPP Report, IPP 9/82]; [H. Verbeek, J. Stober, D. Coster, W. Eckstein, R. Schneider Nucl. Fus. 38 (1998) 12] and a figure of merit (F. of M.) between several materials is proposed which also takes into account the plasma isotope effect in CX erosion.

  2. Studies of tungsten erosion at the inner and outer main chamber wall of the ASDEX Upgrade tokamak

    International Nuclear Information System (INIS)

    Tabasso, A.; Maier, H.; Roth, J.; Krieger, K.

    2001-01-01

    A critical issue for the choice of main chamber first wall materials in future fusion devices such as ITER is the erosion rate due to bombardment by charge-exchange (CX) neutrals. Due to the relatively small flux density of impacting particles, respective measurements are only possible using long term samples (LTS) exposed for a full experimental campaign. In ASDEX Upgrade, CX erosion has been studied extensively for tungsten on the inner heat shield by placing four W coated tiles at different poloidal positions in one toroidal sector. During the same campaign, several LTS were placed at different poloidal and toroidal positions of the outer wall. 13 C and Cu coated graphite probes were also used in order to test and compare W low and medium Z alternatives. The erosion results from the probes are compared with the calculated erosion [W. Eckstein, C. Garcia-Rosales, J. Roth, W. Ottenberger IPP Report, IPP 9/82]; [H. Verbeek, J. Stober, D. Coster, W. Eckstein, R. Schneider Nucl. Fus. 38 (1998) 12] and a figure of merit (F. of M.) between several materials is proposed which also takes into account the plasma isotope effect in CX erosion

  3. Estimation of edge electron temperature profiles via forward modelling of the electron cyclotron radiation transport at ASDEX Upgrade

    International Nuclear Information System (INIS)

    Rathgeber, S K; Barrera, L; Eich, T; Fischer, R; Suttrop, W; Wolfrum, E; Nold, B; Willensdorfer, M

    2013-01-01

    We present a method to obtain reliable edge profiles of the electron temperature by forward modelling of the electron cyclotron radiation transport. While for the core of ASDEX Upgrade plasmas, straightforward analysis of electron cyclotron intensity measurements based on the optically thick plasma approximation is usually justified, reasonable analysis of the steep and optically thin plasma edge needs to consider broadened emission and absorption profiles and radiation transport processes. This is carried out in the framework of integrated data analysis which applies Bayesian probability theory for joint analysis of the electron density and temperature with data of different interdependent and complementary diagnostics. By this means, electron cyclotron radiation intensity delivers highly spatially resolved electron temperature data for the plasma edge. In H-mode, the edge gradient of the electron temperature can be several times higher than the one of the radiation temperature. Furthermore, we are able to reproduce the ‘shine-through’ peak—the observation of increased radiation temperatures at frequencies resonant in the optically thin scrape-off layer. This phenomenon is caused by strongly down-shifted radiation of Maxwellian tail electrons located in the H-mode edge region and, therefore, contains valuable information about the electron temperature edge gradient. (paper)

  4. Hydrogen isotope inventory in the graphite divertor tiles of ASDEX Upgrade as measured by thermal desorption spectroscopy

    International Nuclear Information System (INIS)

    Franzen, P.; Behrisch, R.; Garcia-Rosales, C.; Schleussner, D.; Roesler, D.; Becker, J.; Knapp, W.; Edelmann, C.

    1997-01-01

    The hydrogen and deuterium inventories of the ASDEX Upgrade divertor tiles were measured after the experimental period from December 1994 to July 1995 by thermal desorption spectroscopy (TDS) of samples cut out of the divertor tiles. The samples were heated by electron bombardment up to 2100 K; the released gases were measured by means of a calibrated quadrupole mass spectrometer. The measured hydrogen or deuterium inventories are of the order of 10 23 m -2 . They are larger for samples of the inner divertor than of the outer divertor by a factor of about 2. The largest inventory was found at the separatrix position of the inner divertor. Most of the released hydrogen (H) can be attributed to water adsorbed in the near surface region during the air exposure prior to the TDS measurements. The total inventories measured by TDS exceed the inventories in the near surface region (< 25 μm) measured by ion beam analysis methods by a factor of up to 10. Hence, the total hydrogen retention is governed by the diffusion out of the near surface region deep into the material. The hydrogen and deuterium inventories decreased with increasing surface temperature. (author). 64 refs, 12 figs, 2 tabs

  5. 3D trajectories re-construction of droplets ejected in controlled tungsten melting studies in ASDEX Upgrade

    International Nuclear Information System (INIS)

    Yang, Zhongshi; Krieger, K.; Lunt, T.; Brochard, F.; Briancon, J.-L.; Neu, R.; Dux, R.; Janzer, A.; Potzel, S.; Pütterich, T.

    2013-01-01

    Two fast visible range camera systems with vertically and tangentially oriented crossed viewing fields in the divertor region of ASDEX Upgrade were used to observe tungsten (W) droplets ejected from a melting W-pin into the divertor plasma. To obtain the spatial (3D) trajectories of the tungsten droplets, the trajectory of a given droplet in the (2D) camera image coordinate system was derived for each view separately. From these data, the 3D droplet position was derived by computing the shortest line segment connecting crossed viewing chords to a given droplet taking the centre coordinate of the line segment as actual coordinate. The experimental error of the derived position was estimated from the length of the connecting line segment. In the toroidal direction, the computed trajectories can be described by an analytical transport model for the droplets assuming an initial droplet diameter in the range of 60–100 μm. In the vertical direction the vertical distance droplets travelled when reaching the edge of the viewing field also agrees with the model predictions. However, discrepancies are found with respect to the time point whence a droplet reverts its initial downwards motion due to centrifugal forces exceeding gravity and plasma generated force components

  6. Effects of triangularity on confinement, density limit and profile stiffness of H-modes on ASDEX upgrade

    International Nuclear Information System (INIS)

    Stober, J.; Gruber, O.; Kallenbach, A.; Mertens, V.; Ryter, F.; Staebler, A.; Suttrop, W.; Treutterer, W.

    2000-01-01

    At ASDEX Upgrade the influence of triangularity on the H-mode performance has been studied intensively. It has been found that confinement increases with δ for a fixed line-averaged density. Though confinement decreases with increasing density for all analysed values of δ, H-factors (ITERH-98P) at the Greenwald density could be raised to 1 for the highest δ values achieved so far. The H-mode density limit could be increased by approx. 20%. There is a scatter of about 30% on the confinement data, which is anti-correlated to the average density in the scrape-off layer or the neutral fluxes outside the plasma. For nearly all discharges analysed so far, the temperature profiles are self-similar. This indication of profile stiffness could be verified by changing the heat-flux profile by changing the beam-voltage of the neutral-beam injection (NBI) at high density. At low density, first results indicate a deviation from this stiff behaviour. (author)

  7. Design of a four-channel bolometer module for ASDEX upgrade and tore supra

    International Nuclear Information System (INIS)

    Mueller, E.R.; Weber, G.; Mast, F.; Schramm, G.; Buchelt, E.; Andelfinger, C.

    1985-10-01

    A new small-sized four-bolometer module for application in high-temperature plasma diagnostics has been designed. The four bolometers and the four reference bolometers shielded against radiation are placed side by side on one kapton foil, the entire arrangement occupying an area of 2.0x3.3 cm 2 . The central part of each bolometer consists of a 1.5x4 mm 2 large, 4 to 15 μm thick radiation absorber made of gold, a 7.5 μm thick kapton carrier foil, and a 0.05 μm thick meander-like gold resistor (conduction path width: 30 μm). It offers all the advantages already provided by the well-known ASDEX and JET bolometers, such as very high operating reliability and resistance to nuclear radiation damage. It is optional to enlarge the cooling time constant of the bolometer in a controlled way from a few milliseconds up to several hundreds, thus improving the sensitivity to very weak signals in the low-frequency (<=20 Hz) part of the radiation spectrum, by means of an additional (thin) gold layer that delays the heat losses from the bolometer foil to the cooling body. Since the bolometer is very suitable for AC-bridge electronics and all bridge resistors are arranged on a minimum area interference signals should be suppressed to extremely low levels. (orig.)

  8. Direct measurements of the plasma potential in ELMy H-mode plasma with ball-pen probes on ASDEX Upgrade tokamak

    Czech Academy of Sciences Publication Activity Database

    Adámek, Jiří; Stöckel, Jan; Brotánková, Jana; Horáček, Jan; Rohde, V.; Müller, H. W.; Herrmann, A.; Schrittwieser, R.; Mehlmann, F.; Ionita, C.

    390-391, - (2009), s. 1114-1117 ISSN 0022-3115. [International Conference on Plasma-Surface Interactions in Controlled Fusion Device/18th./. Toledo, 26.05.2008-30.05.2008] R&D Projects: GA AV ČR KJB100430601 Institutional research plan: CEZ:AV0Z20430508 Keywords : Edge plasma * Electric field * ELMs * H-mode * ASDEX-Upgrade Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 1.933, year: 2009 http://dx.doi.org/10.1016/j.jnucmat.2009.01.286

  9. Direct measurements of the plasma potential in ELMy H-mode plasma with ball-pen probes on ASDEX Upgrade tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Adamek, J., E-mail: adamek@ipp.cas.c [Institute of Plasma Physics, Association EURATOM/IPP.CR, Prague, Za Slovankou 3, 182 00, Prague 8 (Czech Republic); Rohde, V.; Mueller, H.W.; Herrmann, A. [Institute of Plasma Physics, Association EURATOM/IPP, Garching (Germany); Ionita, C.; Schrittwieser, R.; Mehlmann, F. [Institute for Ion Physics and Applied Physics, University of Innsbruck, Association EURATOM/OAW (Austria); Stoeckel, J.; Horacek, J.; Brotankova, J. [Institute of Plasma Physics, Association EURATOM/IPP.CR, Prague, Za Slovankou 3, 182 00, Prague 8 (Czech Republic)

    2009-06-15

    Experimental investigations of the plasma potential and electric field were performed for ELMy H-mode plasmas in the vicinity of the limiter shadow of ASDEX Upgrade. A fast reciprocating probe with a probe head containing four ball-pen probes (BPPs) [J. Adamek et al., Czech. J. Phys. 54 (2004) C95 - C99.] was used on the midplane manipulator. Different gradients of the plasma potential were observed during ELMs and in between them. The temporal resolution of the direct plasma potential measurements with BPP was determined by using power-spectra analysis.

  10. Parametric dependencies of the experimental tungsten transport coefficients in ICRH and ECRH assisted ASDEX Upgrade H-modes

    Science.gov (United States)

    Sertoli, M.; Angioni, C.; Odstrcil, T.; ASDEX Upgrade Team; Eurofusion MST1 Team

    2017-11-01

    The profiles of the W transport coefficients have been experimentally calculated for a large database of identical ASDEX Upgrade H-mode discharges where only the radio-frequency (RF) power characteristics have been varied [Angioni et al., Nucl. Fusion 57, 056015 (2017)]. Central ion cyclotron resonance heating (ICRH) in the minority heating scheme has been compared with central and off-axis electron cyclotron resonance heating (ECRH), using both localized and broad heat deposition profiles. The transport coefficients have been calculated applying the gradient-flux relation to the evolution of the intrinsic W density in-between sawtooth cycles as measured using the soft X-ray diagnostic. For both ICRH and ECRH, the major player in reducing the central W density peaking is found to be the reduction of inward pinch and, in the case of ECRH, the rise of an outward convection. The impurity convection increases, from negative to positive, almost linearly with RF-power, while no appreciable changes are observed in the diffusion coefficient, which remains roughly at neoclassical levels independent of RF power or background plasma conditions. The ratio vW/DW is consistent with the equilibrium ∇ n W / n W prior to the sawtooth crash, corroborating the separate estimates of diffusion and convection. These experimental findings are slightly different from previous results obtained analysing the evolution of impurity injections over many sawtooth cycles. Modelling performed using the drift-kinetic code NEO and the gyro-kinetic code GKW (assuming axisymmetry) overestimates the diffusion coefficient and underestimates the experimental positive convection. This is a further indication that magneto-hydrodynamic/neoclassical models accounting for 3D effects may be needed to characterize impurity transport in sawtoothing tokamak plasmas.

  11. Spatiotemporal response of plasma edge density and temperature to non-axisymmetric magnetic perturbations at ASDEX Upgrade

    International Nuclear Information System (INIS)

    Fischer, R; Fuchs, J C; McDermott, R; Rathgeber, S K; Suttrop, W; Wolfrum, E; Willensdorfer, M

    2012-01-01

    Non-axisymmetric magnetic perturbations (MPs) were successfully applied at ASDEX Upgrade to substantially reduce the plasma energy loss and peak divertor power load that occur concomitant with type-I edge localized modes (ELMs). The response of electron density edge profiles and temperature and pressure pedestal-top values to MPs are reported. ELM mitigation is observed above an edge density threshold and independent of the MPs being resonant or non-resonant with the edge safety factor. The edge electron collisionality appears not to be appropriate to separate mitigated from non-mitigated discharges for the present high-collisionality plasmas. No significant change in the position or gradient of the edge density profile could be observed for the transition into the ELM-mitigated phase, except from the effect of the three-dimensional MP field which leads to an apparent profile shift. An increase in the density and decrease in the temperature at the pedestal-top balance such that the pressure saturates at the value of the pre-mitigated phase. The plasma stored energy, the normalized plasma pressure, and the H-mode quality factor follow closely the evolution of the pedestal-top pressure and thus remain almost unaffected. The temporal evolution of the ion effective charge shows that the impurity content does not increase although flushing through type-I ELMs is missing. The type-I ELMs are replaced in the mitigated phase by small-scale and high-frequency edge perturbations. The effect of the small bursts on the density profile, which is correlated with a transient increase of the divertor thermoelectric current, is small compared with the effect of the type-I ELMs. The residual scatter of the profiles in the mitigated phase is small directly after the transition into the ELM-mitigated phase and increases again when the pressure saturates at the value of the pre-mitigated phase. (paper)

  12. Data acquisition and real time signal processing of plasma diagnostics on ASDEX Upgrade using LabVIEW RT

    Energy Technology Data Exchange (ETDEWEB)

    Giannone, L.; Scarabosio, A.; Eich, T.; Fuchs, C.; Haas, G.; Kallenbach, A.; McCarthy, P.; Mlynek, A.; Neu, G.; Reich, M.; Schneider, W.; Schuhbeck, K.; Treutterer, W.; Zehetbauer, T.; Asdex, Upgrade Team [Max-Planck-Institut fur Plasmaphysik, Garching (Germany); Cerna, M.; Wenzel, L.; Concezzi, S.; Debelle, T.; Marker, B.; Munroe, M.; Petersen, N.; Vrancic, A. [National Instruments Corporation, Austin (United States); Marquardt, M.; Sachtleben, J. [Max-Planck-Institute for Plasmaphysics, Teilinstitut Greifswald (Germany)

    2009-07-01

    There are 5 plasma diagnostics using LabVIEW RT for data acquisition and control on ASDEX Upgrade. These diagnostics are integrated into the VxWorks control system by the exchange of XML files. Real time communication to the control system is possible by Ethernet using UDP or by reflective memory using a dedicated fiber optic cable. The bolometer and manometer data acquisition systems are described, they use FPGA cards to process raw data in real time. The absorbed power of the bolometer foil is calculated in real time on the FPGA. The radiation peaking factor is also calculated in real time and is used for feedback control of the discharge. The manometer uses 8 analog inputs and 4 analog outputs of a FPGA card to provide PID control of the electron current emission of a filament. The electron and ion currents are acquired at 750 kHz and the neutral gas pressures of 4 manometers are calculated in real time on a FPGA card at up to 10 kHz. The magnetic equilibrium diagnostic acquires 80 magnetic probe and flux loop signals at 10 kHz. The 95 plasma position and shape parameters and magnetic flux surfaces are calculated in real time. The function parameterization algorithm used to calculate the magnetic flux surfaces in real time requires the multiplication of a matrix of dimension 2691*231 with a vector of length 231. This matrix and vector multiplication is solved through parallel computing on a dual quad-core computer and the execution time of this operation is reduced by a factor of four compared to calculation on a single core. This document is composed of an abstract followed by a poster. (authors)

  13. Electrical and mechanical adaptation of commercially available power inverter modules for BUSSARD – The power supply of ASDEX Upgrade in vessel saddle coils

    Energy Technology Data Exchange (ETDEWEB)

    Rott, Michael, E-mail: Michael.Rott@ipp.mpg.de [Max Planck Institute for Plasma Physics, Boltzmannstrasse 2, D-85748 Garching (Germany); Arden, Nils; Eixenberger, Horst [Max Planck Institute for Plasma Physics, Boltzmannstrasse 2, D-85748 Garching (Germany); Klädtke, Kevin [Technical University Munich, Arcisstraße 21, D-80333 München (Germany); Teschke, Markus; Suttrop, Wolfgang [Max Planck Institute for Plasma Physics, Boltzmannstrasse 2, D-85748 Garching (Germany)

    2015-10-15

    Highlights: • Mechanical design of inverters for restricted space and good mountability. • Supply of DC link possible with thyristor converter. • Plant safety by independent overcurrent protections and a commercially arc detection system. • Ground fault detection by fast differential current measurement. • Possibilities of changing the inductance of a two windings iron core choke. - Abstract: To supply the ASDEX Upgrade's B-coils with AC current up to 1.3 kA{sub p} at 500 Hz with arbitrary waveforms, a set of 16 inverters has been designed and partially built. To keep cost and development time low, commercially available power modules are used and existing current converters feed the DC links. Three power modules are mounted in one cubicle for realizing a three level neutral point clamped (NPC) topology with lowest possible inductivity and making the most of the limited space available. The paper presents the effort and steps required to adapt standard power blocks towards the needs of the ASDEX Upgrade power supply as well as the mechanical optimizations for good mountability, flexibility and scalability. Besides, solutions for mandatory personnel safety and plant safety are presented.

  14. A new thermal He-beam diagnostic for electron density and temperature measurements in the scrape-off layer of ASDEX Upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Griener, Michael; Wolfrum, Elisabeth; Eich, Thomas; Herrmann, Albrecht; Rohde, Volker [Max Planck Institute for Plasma Physics, Garching (Germany); Schmitz, Oliver [Engineering Physics Department, University of Wisconsin-Madison (United States); Stroth, Ulrich [Max Planck Institute for Plasma Physics, Garching (Germany); Physik Department E28, Technische Universitaet Muenchen, Garching (Germany); Collaboration: the ASDEX Upgrade Team

    2015-05-01

    In a nuclear fusion device power is exhausted across the last closed flux surface into the so-called 'scrape-off layer', SOL. In order to study the transport dynamics to (a) the divertor via parallel heat flux and (b) to the wall via filaments, a diagnostic for the determination of n{sub e} and T{sub e} with high spatial and temporal resolution is required. Although the diagnostic capabilities of the ASDEX Upgrade edge plasma are excellent, there is a lack of spatially and temporally highly resolved electron temperature measurements in the SOL. Therefore a piezo valve will be installed in ASDEX Upgrade in April 2015. It allows fast chopping of a thermal He-beam which is part of the new diagnostic. In the first campaign, existing lines of sight of the CXRS diagnostic will be used to measure various He I transitions to confirm the collisional radiative model for He. The principle of the thermal He-diagnostic as well as calculations of the achievable spatial resolution of the initial set-up are presented.

  15. Electrical and mechanical adaptation of commercially available power inverter modules for BUSSARD – The power supply of ASDEX Upgrade in vessel saddle coils

    International Nuclear Information System (INIS)

    Rott, Michael; Arden, Nils; Eixenberger, Horst; Klädtke, Kevin; Teschke, Markus; Suttrop, Wolfgang

    2015-01-01

    Highlights: • Mechanical design of inverters for restricted space and good mountability. • Supply of DC link possible with thyristor converter. • Plant safety by independent overcurrent protections and a commercially arc detection system. • Ground fault detection by fast differential current measurement. • Possibilities of changing the inductance of a two windings iron core choke. - Abstract: To supply the ASDEX Upgrade's B-coils with AC current up to 1.3 kA_p at 500 Hz with arbitrary waveforms, a set of 16 inverters has been designed and partially built. To keep cost and development time low, commercially available power modules are used and existing current converters feed the DC links. Three power modules are mounted in one cubicle for realizing a three level neutral point clamped (NPC) topology with lowest possible inductivity and making the most of the limited space available. The paper presents the effort and steps required to adapt standard power blocks towards the needs of the ASDEX Upgrade power supply as well as the mechanical optimizations for good mountability, flexibility and scalability. Besides, solutions for mandatory personnel safety and plant safety are presented.

  16. Far-reaching Impact of Intermittent Transport across the Scrape-off Layer: Latest Results from ASDEX Upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Kocan, M.; Muller, W.; Conway, G.; De Marne, P.; Eich, T.; Fischer, R.; Fuchs, C.; Herrmann, A.; Ionita, C.; Kallenbach, A.; Lunt, T.; Maraschek, M.; Muller, S.; Nold, B.; Ribeiro, T.; Rohde, V.; Scott, B.; Stroth, U.; Suttrop, W.; Wolfrum, E., E-mail: martin.kocan@ipp.mpg.de [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, Garching (Germany); Adamek, J.; Horacek, J.; Komm, M. [Association EURATOM-IPP CR, Prague (Czech Republic); Gennrich, F.; Maszl, C.; Mehlmann, F.; Schrittwieser, R. [Institute for Ion Physics and Applied Physics, Association Euratom-OAW (Austria); Huang, Z. [Institut fuer Plasmaforschung, Universitat Stuttgart, Stuttgart (Germany)

    2012-09-15

    Full text: Latest research of intermittent transport in the scrape-off layer (SOL) of the ASDEX Upgrade tokamak is presented. Near the separatrix the fluctuations of the plasma and the floating potentials, measured by various Langmuir probes (LPs), are found to be anti-correlated due to fluctuations of the electron temperature. This indicates that, in contrast to a widely used experimental practice, a free exchange of both potentials is unjustified and can lead to significant error. Measurements of ion energies in turbulent L-mode and ELM filaments were carried out using a retarding field analyzer. In L-mode plasma, the filament ion temperature measured at 2 cm outside the separatrix is 80 - 110 eV, i.e., 3 - 4x the background ion temperature. Turbulent filaments also convect plasma to the wall with larger density than the background plasma density. Qualitatively similar observations were obtained during inter-ELM periods. Such enhanced particle and energy fluxes can potentially raise the erosion of the first wall in ITER. The ion temperature averaged over an ELM measured 35 - 60 mm outside the separatrix is in the range of 20 - 200 eV (5 - 50% of the pedestal top ion temperature). This demonstrates that ELM filaments carry hot ions over large radial distances in the SOL, which, in turn, can lead to enhanced sputtering from the first wall in future tokamaks. Lowest ion energies are observed during ELMs mitigated by in-vessel magnetic perturbations (MPs). The ELM ion temperature in the far SOL is found to increase with the ELM energy, indicating that on average the filaments in large ELMs propagate faster radially. The filamentary structure of the ion current density measured by LPs at the outboard mid-plane during mitigated ELMs is qualitatively similar to that observed during type I ELMs. The amplitude of the ion current density decreases only slightly when ELMs are mitigated, but, in contrast to type I ELMs, bursts of the ion current are observed throughout the

  17. Fast-ion losses induced by ELMs and externally applied magnetic perturbations in the ASDEX Upgrade tokamak

    International Nuclear Information System (INIS)

    Garcia-Munoz, M; Rodriguez-Ramos, M; Äkäslompolo, S; De Marne, P; Dunne, M G; Dux, R; Fietz, S; Fuchs, C; Geiger, B; Herrmann, A; Hoelzl, M; Kurzan, B; McDermott, R M; Strumberger, E; Evans, T E; Ferraro, N M; Pace, D C; Lazanyi, N; Nocente, M; Shinohara, K

    2013-01-01

    Phase-space time-resolved measurements of fast-ion losses induced by edge localized modes (ELMs) and ELM mitigation coils have been obtained in the ASDEX Upgrade tokamak by means of multiple fast-ion loss detectors (FILDs). Filament-like bursts of fast-ion losses are measured during ELMs by several FILDs at different toroidal and poloidal positions. Externally applied magnetic perturbations (MPs) have little effect on plasma profiles, including fast-ions, in high collisionality plasmas with mitigated ELMs. A strong impact on plasma density, rotation and fast-ions is observed, however, in low density/collisionality and q 95 plasmas with externally applied MPs. During the mitigation/suppression of type-I ELMs by externally applied MPs, the large fast-ion bursts observed during ELMs are replaced by a steady loss of fast-ions with a broad-band frequency and an amplitude of up to an order of magnitude higher than the neutral beam injection (NBI) prompt loss signal without MPs. Multiple FILD measurements at different positions, indicate that the fast-ion losses due to static 3D fields are localized on certain parts of the first wall rather than being toroidally/poloidally homogeneously distributed. Measured fast-ion losses show a broad energy and pitch-angle range and are typically on banana orbits that explore the entire pedestal/scrape-off-layer (SOL). Infra-red measurements are used to estimate the heat load associated with the MP-induced fast-ion losses. The heat load on the FILD detector head and surrounding wall can be up to six times higher with MPs than without 3D fields. When 3D fields are applied and density pump-out is observed, an enhancement of the fast-ion content in the plasma is typically measured by fast-ion D-alpha (FIDA) spectroscopy. The lower density during the MP phase also leads to a deeper beam deposition with an inward radial displacement of ≈2 cm in the maximum of the beam emission. Orbit simulations are used to test different models for 3D

  18. Density dependence of SOL power width in ASDEX upgrade L-Mode

    Directory of Open Access Journals (Sweden)

    B. Sieglin

    2017-08-01

    A recent study [4] with an open divertor configuration found an asymmetry of the power fall-off length between inner and outer target with a smaller power fall-off length λq,i on the inner divertor target. Measurements with a closed divertor configuration find a similar asymmetry for low recycling divertor conditions. It is found, in the experiment, that the in/out asymmetry λq,i/λq,o is strongly increasing with increasing density. Most notably the heat flux density at the inner divertor target is reducing with increasing λq,i whilst the total power onto each divertor target stays constant. It is found that λq,o exhibits no significant density dependence for hydrogen and deuterium but increases with about the square root of the electron density for helium. The difference between H,D and He could be due to the different recycling behaviour in the divertor. These findings may help current modelling attempts to parametrize the density dependence of the widening of the power channel and thus allow for detailed comparison to both divertor effects like recycling or increased upstream SOL cross field transport.

  19. Profile measurements of the electron temperature on the ASDEX Upgrade, COMPASS, and ISTTOK tokamak using Thomson scattering, triple, and ball-pen probes

    Czech Academy of Sciences Publication Activity Database

    Adámek, Jiří; Müller, H.W.; Silva, C.; Schrittwieser, R.; Ionita, C.; Mehlmann, F.; Costea, S.; Horáček, Jan; Kurzan, B.; Bílková, Petra; Böhm, Petr; Aftanas, Milan; Vondráček, Petr; Stöckel, Jan; Pánek, Radomír; Fernandes, H.; Figueiredo, H.

    2016-01-01

    Roč. 87, č. 4 (2016), č. článku 043510. ISSN 0034-6748 R&D Projects: GA ČR(CZ) GA15-10723S; GA ČR(CZ) GAP205/12/2327; GA ČR(CZ) GA14-35260S; GA MŠk(CZ) LM2011021 Institutional support: RVO:61389021 Keywords : ball- pen probe (BPP) * ASDEX Upgrade * Langmuir probe (LP) * ISTTOK (Instituto Superior Tecnico TOKamak) * COMPASS (COMPact ASSembly), Subject RIV: BL - Plasma and Gas Discharge Physics OBOR OECD: 2.11 Other engineering and technologies Impact factor: 1.515, year: 2016 http://scitation.aip.org/content/aip/journal/rsi/87/4/10.1063/1.4945797

  20. Profile measurements of the electron temperature on the ASDEX Upgrade, COMPASS, and ISTTOK tokamak using Thomson scattering, triple, and ball-pen probes

    Czech Academy of Sciences Publication Activity Database

    Adámek, Jiří; Müller, H.W.; Silva, C.; Schrittwieser, R.; Ionita, C.; Mehlmann, F.; Costea, S.; Horáček, Jan; Kurzan, B.; Bílková, Petra; Böhm, Petr; Aftanas, Milan; Vondráček, Petr; Stöckel, Jan; Pánek, Radomír; Fernandes, H.; Figueiredo, H.

    2016-01-01

    Roč. 87, č. 4 (2016), č. článku 043510. ISSN 0034-6748 R&D Projects: GA ČR(CZ) GA15-10723S; GA ČR(CZ) GAP205/12/2327; GA ČR(CZ) GA14-35260S; GA MŠk(CZ) LM2011021 Institutional support: RVO:61389021 Keywords : ball-pen probe (BPP) * ASDEX Upgrade * Langmuir probe (LP) * ISTTOK (Instituto Superior Tecnico TOKamak) * COMPASS (COMPact ASSembly), Subject RIV: BL - Plasma and Gas Discharge Physics OBOR OECD: 2.11 Other engineering and technologies Impact factor: 1.515, year: 2016 http://scitation.aip.org/content/aip/journal/rsi/87/4/10.1063/1.4945797

  1. The effect of off-axis neutral beam injection on sawtooth stability in ASDEX Upgrade and Mega-Ampere Spherical Tokamak

    International Nuclear Information System (INIS)

    Chapman, I. T.; de Bock, M. F.; Pinches, S. D.; Turnyanskiy, M. R.; Igochine, V. G.; Maraschek, M.; Tardini, G.

    2009-01-01

    Sawtooth behavior has been investigated in plasmas heated with off-axis neutral beam injection in ASDEX Upgrade [A. Herrmann and O. Gruber, Fusion Sci. Technol. 44, 569 (2003)] and the Mega-Ampere Spherical Tokamak (MAST) [A. Sykes et al., Nucl. Fusion 41, 1423 (2001)]. Provided that the fast ions are well confined, the sawtooth period is found to decrease as the neutral beam is injected further off-axis. Drift kinetic modeling of such discharges qualitatively shows that the passing fast ions born outside the q=1 rational surface can destabilize the n=1 internal kink mode, thought to be related to the sawtooth instability. This effect can be enhanced by optimizing the deposition of the off-axis beam energetic particle population with respect to the mode location.

  2. A new B-dot probe-based diagnostic for amplitude, polarization, and wavenumber measurements of ion cyclotron range-of frequency fields on ASDEX Upgrade

    International Nuclear Information System (INIS)

    Ochoukov, R.; Bobkov, V.; Faugel, H.; Fünfgelder, H.; Noterdaeme, J.-M.

    2015-01-01

    A new B-dot probe-based diagnostic has been installed on an ASDEX Upgrade tokamak to characterize ion cyclotron range-of frequency (ICRF) wave generation and interaction with magnetized plasma. The diagnostic consists of a field-aligned array of B-dot probes, oriented to measure fast and slow ICRF wave fields and their field-aligned wavenumber (k // ) spectrum on the low field side of ASDEX Upgrade. A thorough description of the diagnostic and the supporting electronics is provided. In order to compare the measured dominant wavenumber of the local ICRF fields with the expected spectrum of the launched ICRF waves, in-air near-field measurements were performed on the newly installed 3-strap ICRF antenna to reconstruct the dominant launched toroidal wavenumbers (k tor ). Measurements during a strap current phasing scan in tokamak discharges reveal an upshift in k // as strap phasing is moved away from the dipole configuration. This result is the opposite of the k tor trend expected from in-air near-field measurements; however, the near-field based reconstruction routine does not account for the effect of induced radiofrequency (RF) currents in the passive antenna structures. The measured exponential increase in the local ICRF wave field amplitude is in agreement with the upshifted k // , as strap phasing moves away from the dipole configuration. An examination of discharges heated with two ICRF antennas simultaneously reveals the existence of beat waves at 1 kHz, as expected from the difference of the two antennas’ operating frequencies. Beats are observed on both the fast and the slow wave probes suggesting that the two waves are coupled outside the active antennas. Although the new diagnostic shows consistent trends between the amplitude and the phase measurements in response to changes applied by the ICRF antennas, the disagreement with the in-air near-field measurements remains. An electromagnetic model is currently under development to address this issue

  3. A new B-dot probe-based diagnostic for amplitude, polarization, and wavenumber measurements of ion cyclotron range-of frequency fields on ASDEX Upgrade

    Science.gov (United States)

    Ochoukov, R.; Bobkov, V.; Faugel, H.; Fünfgelder, H.; Noterdaeme, J.-M.

    2015-11-01

    A new B-dot probe-based diagnostic has been installed on an ASDEX Upgrade tokamak to characterize ion cyclotron range-of frequency (ICRF) wave generation and interaction with magnetized plasma. The diagnostic consists of a field-aligned array of B-dot probes, oriented to measure fast and slow ICRF wave fields and their field-aligned wavenumber (k//) spectrum on the low field side of ASDEX Upgrade. A thorough description of the diagnostic and the supporting electronics is provided. In order to compare the measured dominant wavenumber of the local ICRF fields with the expected spectrum of the launched ICRF waves, in-air near-field measurements were performed on the newly installed 3-strap ICRF antenna to reconstruct the dominant launched toroidal wavenumbers (ktor). Measurements during a strap current phasing scan in tokamak discharges reveal an upshift in k// as strap phasing is moved away from the dipole configuration. This result is the opposite of the ktor trend expected from in-air near-field measurements; however, the near-field based reconstruction routine does not account for the effect of induced radiofrequency (RF) currents in the passive antenna structures. The measured exponential increase in the local ICRF wave field amplitude is in agreement with the upshifted k//, as strap phasing moves away from the dipole configuration. An examination of discharges heated with two ICRF antennas simultaneously reveals the existence of beat waves at 1 kHz, as expected from the difference of the two antennas' operating frequencies. Beats are observed on both the fast and the slow wave probes suggesting that the two waves are coupled outside the active antennas. Although the new diagnostic shows consistent trends between the amplitude and the phase measurements in response to changes applied by the ICRF antennas, the disagreement with the in-air near-field measurements remains. An electromagnetic model is currently under development to address this issue.

  4. Micro-NRA and micro-3HIXE with 3He microbeam on samples exposed in ASDEX Upgrade and Pilot-PSI machines

    Science.gov (United States)

    Kelemen, Mitja; Založnik, Anže; Vavpetič, Primož; Pečovnik, Matic; Pelicon, Primož; Hakola, Antti; Lahtinen, Aki; Karhunen, Juuso; Piip, Kaarel; Paris, Peeter; Laan, Matti; Krieger, Karl; Oberkofler, Martin; van der Meiden, Hennie; Markelj, Sabina

    2017-08-01

    Micro nuclear reaction analysis (micro-NRA) exploiting the nuclear reaction D(3He,p)4He was used for post-mortem analyses of special marker samples, exposed to deuterium plasma inside ASDEX Upgrade (AUG) tokamak and to the deuterium plasma jet in the Pilot-PSI linear plasma gun. Lateral concentration profiles of deuterium and erosion/deposition profiles of the marker materials were obtained by a combination of micro-NRA and particle induced X-ray emission by 3He beam (3HIXE). In the case of AUG samples, where 25 nm thick W marker layers had been deposited on unpolished and polished graphite substrates, the effect of surface roughness on local erosion and deposition was also investigated. The lateral distribution of W concentration showed that erosion is much more distinct in the case of polished samples and the resulting surface shows a ;leopard; skin pattern of W accumulated on carbon aggregates left on the surface from polishing. The Pilot-PSI samples indicated preferential accumulation of deuterium a few mm off from the centre of the region affected by the plasma beam. This is connected with the largest surface modifications while the thick deposited layers at the centre do not favour deuterium retention per se. The results were cross correlated with those obtained using laser-induced breakdown spectroscopy (LIBS). With its quantitative abilities, micro-NRA provided essential calibration data for in situ LIBS operation, as well as for complementary post mortem Secondary Ion Mass Spectroscopy (SIMS).

  5. Localized Scrape-Off Layer density modifications by Ion Cyclotron near fields in JET and ASDEX-Upgrade L-mode plasmas

    Science.gov (United States)

    Colas, L.; Jacquet, Ph.; Van Eester, D.; Bobkov, V.; Brix, M.; Meneses, L.; Tamain, P.; Marsen, S.; Silva, C.; Carralero, D.; Kočan, M.; Müller, H.-W.; Crombé, K.; Křivska, A.; Goniche, M.; Lerche, E.; Rimini, F. G.; JET-EFDA Contributors

    2015-08-01

    Combining Lithium beam emission spectroscopy and edge reflectometry, localized Scrape-Off Layer (SOL) density modifications by Ion Cyclotron Range of Frequencies (ICRF) near fields were characterized in JET L-mode plasmas. When using the ICRF wave launchers connected magnetically to the Li-beam chord, the density decreased more steeply 2-3 cm outside the last closed flux surface (mapped onto the outer mid-plane) and its value at the outer limiter radial position was half the ohmic value. The depletion depends on the ICRF power and on the phasing between adjacent radiating straps. Convection due to ponderomotive effects and/or E × B0 drifts is suspected: during ICRF-heated H-mode discharges in 2013, DC potentials up to 70 V were measured locally in the outer SOL by a floating reciprocating probe, located toroidally several metres from the active antennas. These observations are compared with probe measurements on ASDEX-Upgrade. Their implications for wave coupling, heat loads and impurity production are discussed.

  6. Characterization of Scrape-Off layer turbulence changes induced by a non-axisymmetric magnetic perturbation in an ASDEX upgrade low density L-mode

    International Nuclear Information System (INIS)

    Mueller, H.W.; Carralero, D.; Birkenmeier, G.; Conway, G.D.; Fischer, R.; Happel, T.; Manz, P.; Suttrop, W.; Wolfrum, E.

    2014-01-01

    In the tokamak ASDEX Upgrade the influence of a non-axisymmetric n = 2 error field on the turbulence in the far scrape-off layer of a low density L-mode discharge has been studied. There is no density pump-out with the non-axisymmetric perturbation but an increase of the scrape-off layer density at the outer midplane. While the relative ion saturation current fluctuation level in the far scrape-off layer is decreasing, the skewness rises and especially the excess kurtosis grows by a factor of 1.5-3. The frequency of intermittent events (blobs) is increasing by 50 %. Also the poloidal velocity grows with the magnetic perturbation while the typical turbulent structure size becomes smaller by a factor 5-10 about 20-25 mm outside the separatrix. The local spectral density has been calculated from a two-point measurement of the ion saturation current. It is used to derive a dispersion relation. Two poloidal propagation velocities depending on the wave number have been found. One is an upper limit for the bulk E x B velocity and the second one the lower limit of the phase velocity. There is a significant contribution of the phase velocity to the propagation speed in the far scrape-off layer. (copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  7. ERO and PIC simulations of gross and net erosion of tungsten in the outer strike-point region of ASDEX Upgrade

    Directory of Open Access Journals (Sweden)

    A. Hakola

    2017-08-01

    Full Text Available We have modelled net and gross erosion of W in low-density l-mode plasmas in the low-field side strike point region of ASDEX Upgrade by ERO and Particle-in-Cell (PIC simulations. The observed net-erosion peak at the strike point was mainly due to the light impurities present in the plasma while the noticeable net-deposition regions surrounding the erosion maximum could be attributed to the strong E ×B drift and the magnetic field bringing eroded particles from a distance of several meters towards the private flux region. Our results also imply that the role of cross-field diffusion is very small in the studied plasmas. The simulations indicate net/gross erosion ratio of 0.2–0.6, which is in line with the literature data and what was determined spectroscopically. The deviations from the estimates extracted from post-exposure ion-beam-analysis data (∼0.6–0.7 are most likely due to the measured re-deposition patterns showing the outcomes of multiple erosion-deposition cycles.

  8. Low-noise cable for diagnostics, control and instrumentation of the ASDEX tokamak fusion experiment

    International Nuclear Information System (INIS)

    Gernhardt, J.

    1988-11-01

    ASDEX (Axially Symmetric Divertor EXperiment) is a large tokamak (R=1.65 m; a=0.4 m) with an air transformer. The relatively large stray field, Bz=10 mT=(100 G); for ρ=5 m, Bz=40 mT=(400 G); for ρ=3 m, BΦ=0.3 T=(3 kG); for ρ=3m, compared with that of an iron transformer, and the cable length 1≤30 m from the experiment to the control room, make mainly the magnetically induced and capacitively coupled noise signal in the cable relatively high. As a result of neutral injection (> 4 MW; 40 kV) and lower hybrid ion cyclotron and Alfven wave heating strong E-fields are produced and noise is coupled into the cables. These magnetic and electric field gradients during the plasma shot vary with time and location. This report tries to show how these noise signals can be reduced without reducing the broadcast frequency of the signal. The Electro Magnetic Compatibility and Interference (EMC, EMI) are discussed. The cost of diagnostic cable, connectors and cable ducts without mounting is approximately DM 700,000.--. (orig.)

  9. Proposal to upgrade the MIPP experiment

    Energy Technology Data Exchange (ETDEWEB)

    Isenhower, D.; Sadler, M.; Towell, R.; Watson, S. [Abilene Christian Univ., TX (United States); Peterson, R. J. [Univ. of Colorado, Boulder, CO (United States); Baker, W.; Carey, D.; Christian, D.; Demarteau, M.; Jensen, D.; Johnstone, C.; Meyer, H.; Raja, R.; Ronzhin, A.; Solomey, N.; Wester, W. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Gutbrod, H.; Peters, K. [GSI-Darmstadt (Germany); Feldman, G. [Harvard Univ., Cambridge, MA (United States); Torun, Y. [Illinois Inst. of Technology, Chicago, IL (United States); Messier, M. D.; Paley, J. [Indiana Univ., Bloomington, IN (United States)

    2006-09-01

    The upgraded MIPP physics results are needed for the support of NuMI projects, atmospheric cosmic ray and neutrino programs worldwide and will permit a systematic study of non-perturbative QCD interactions. The MIPP TPC is the largest contributor to the MIPP event size by far. Its readout system and electronics were designed in the 1990's and limit it to a readout rate of 60 Hz in simple events and {approx} 20 Hz in complicated events. With the readout chips designed for the ALICE collaboration at the LHC, we propose a low cost scheme of upgrading the MIPP data acquisition speed to 3000 Hz. This will also enable us to measure the medium energy numi target to be used for the NOvA/MINERvA experiments. We outline the capabilities of the upgraded MIPP detector to obtain high statistics particle production data on a number of nuclei that will help towards the understanding and simulation of hadronic showers in matter. Measurements of nitrogen cross sections will permit a better understanding of cosmic ray shower systematics in the atmosphere. In addition, we explore the possibilities of providing tagged neutral beams using the MIPP spectrometer that may be crucial for validating the Particle Flow Algorithm proposed for calorimeters for the International Linear Collider detectors. Lastly, we outline the physics potential of such a detector in understanding non-perturbative QCD processes.

  10. Extension of the ECRH operational space with O2 and X3 heating schemes to control tungsten accumulation in ASDEX Upgrade

    Science.gov (United States)

    Höhnle, H.; Stober, J.; Herrmann, A.; Kasparek, W.; Leuterer, F.; Monaco, F.; Neu, R.; Schmid-Lorch, D.; Schütz, H.; Schweinzer, J.; Stroth, U.; Wagner, D.; Vorbrugg, S.; Wolfrum, E.; ASDEX Upgrade Team

    2011-08-01

    ASDEX Upgrade has been operated with tungsten-coated plasma-facing components for several years. H-mode operation with good confinement has been demonstrated. Nevertheless, purely neutral beam injection-heated H-modes with reduced gas puff, moderate heating power or/and increased triangularity tend to accumulate tungsten, followed by a radiative collapse. Under these conditions, central electron heating with electron cyclotron resonance heating (ECRH), usually in X2 polarization, changes the impurity transport in the plasma centre, reducing the central tungsten concentration and, in many cases, stabilizing the plasma. In order to extend the applicability of central ECRH to a wider range of magnetic field and plasma current additional ECRH schemes with reduced single-pass absorption have been implemented: X3 heating allows us to reduce the magnetic field by 30%, such that the first H-modes with an ITER-like value of the safety factor of q95 = 3 could be run in the tungsten-coated device. O2 heating increases the cutoff density by a factor of 2 allowing higher currents and triangularities to be addressed. For both schemes, scenarios have been developed to cope with the associated reduced absorption. In the case of central X3 heating, the X2 resonance lies close to the pedestal top at the high-field side of the plasma, serving as a beam dump. For O2, holographic mirrors have been developed which guarantee a second pass through the plasma centre. The beam position on these reflectors is controlled by fast thermocouples. Stray-radiation protection has been implemented using sniffer probes.

  11. Extension of the ECRH operational space with O2 and X3 heating schemes to control tungsten accumulation in ASDEX Upgrade

    International Nuclear Information System (INIS)

    Hoehnle, H.; Kasparek, W.; Stroth, U.; Stober, J.; Herrmann, A.; Leuterer, F.; Monaco, F.; Neu, R.; Schmid-Lorch, D.; Schuetz, H.; Schweinzer, J.; Wagner, D.; Vorbrugg, S.; Wolfrum, E.

    2011-01-01

    ASDEX Upgrade has been operated with tungsten-coated plasma-facing components for several years. H-mode operation with good confinement has been demonstrated. Nevertheless, purely neutral beam injection-heated H-modes with reduced gas puff, moderate heating power or/and increased triangularity tend to accumulate tungsten, followed by a radiative collapse. Under these conditions, central electron heating with electron cyclotron resonance heating (ECRH), usually in X2 polarization, changes the impurity transport in the plasma centre, reducing the central tungsten concentration and, in many cases, stabilizing the plasma. In order to extend the applicability of central ECRH to a wider range of magnetic field and plasma current additional ECRH schemes with reduced single-pass absorption have been implemented: X3 heating allows us to reduce the magnetic field by 30%, such that the first H-modes with an ITER-like value of the safety factor of q 95 = 3 could be run in the tungsten-coated device. O2 heating increases the cutoff density by a factor of 2 allowing higher currents and triangularities to be addressed. For both schemes, scenarios have been developed to cope with the associated reduced absorption. In the case of central X3 heating, the X2 resonance lies close to the pedestal top at the high-field side of the plasma, serving as a beam dump. For O2, holographic mirrors have been developed which guarantee a second pass through the plasma centre. The beam position on these reflectors is controlled by fast thermocouples. Stray-radiation protection has been implemented using sniffer probes.

  12. Velocity-space sensitivities of neutron emission spectrometers at the tokamaks JET and ASDEX upgrade in deuterium plasmas

    DEFF Research Database (Denmark)

    Jacobsen, A.S.; Binda, F.; Cazzaniga, C.

    2017-01-01

    systems such as neutral beam injection and ion cyclotron resonance heating. In order to diagnose these fast ions, several different fast-ion diagnostics have been developed and implemented in the various experiments around the world. The velocity-space sensitivities of fast-ion diagnostics are given by so......Future fusion reactors are foreseen to be heated by the energetic alpha particles produced in fusion reactions. For this to happen, it is important that the energetic ions are sufficiently confined. In present day fusion experiments, energetic ions are primarily produced using external heating...

  13. EMC3-Eirene simulations of gas puff effects on edge density and ICRF coupling in ASDEX Upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Wei; Noterdaeme, Jean-Marie [Max Planck Institute for Plasma Physics, Garching (Germany); University of Ghent, Ghent (Belgium); Coster, David; Lunt, Tilmann; Bobkov, Volodymyr; Feng, Yuehe [Max Planck Institute for Plasma Physics, Garching (Germany); Collaboration: ASDEX Upgrade team

    2015-05-01

    Ion cyclotron range of frequency (ICRF) heating relies on the Fast Wave (FW) to transport the power from the edge (the antenna) to the plasma center. Since the FW is evanescent below a critical density (typically in the 10{sup 18} m{sup -3} range), the wave does not propagate in the region where the density is below this value in the very edge of the plasma. The coupling depends strongly on the width of this region. The distance between the ICRF antenna and the FW cut-off layer can be made smaller by increasing the edge density in front of the ICRF antenna. Previous experiments in many tokamaks and preliminary simulation results for AUG and JET with EDGE2D-EIRENE show that the edge density could indeed be increased with gas puffing at the top of the vessel or in the midplane. But the 2D code cannot quantitatively reproduce the experimental results, mainly due to the assumptions of toroidal axisymmetry. EMC3-EIRENE is a 3D Edge Monte Carlo plasma fluid transport code. By including the toroidal nonaxisymmetric plasma facing components and 3D positions of gas valves in the code, the simulations can be made more realistic. We will show first simulation results of the code and a comparison to experiments.

  14. Electron temperature and pressure at the edge of ASDEX Upgrade plasmas. Estimation via electron cyclotron radiation and investigations on the effect of magnetic perturbations

    International Nuclear Information System (INIS)

    Rathgeber, Sylvia K.

    2013-01-01

    Understanding and control of the plasma edge behaviour are essential for the success of ITER and future fusion plants. This requires the availability of suitable methods for assessing the edge parameters and reliable techniques to handle edge phenomena, e.g. to mitigate 'Edge Localized Modes' (ELMs) - a potentially harmful plasma edge instability. This thesis introduces a new method for the estimation of accurate edge electron temperature profiles by forward modelling of the electron cyclotron radiation transport and demonstrates its successful application to investigate the impact of Magnetic Perturbation (MP) fields used for ELM mitigation on the edge kinetic data. While for ASDEX Upgrade bulk plasmas, straightforward analysis of the measured electron cyclotron intensity spectrum based on the optically thick plasma approximation is usually justified, reasonable analysis of the steep and optically thin edge region relies on full treatment of the radiation transport considering broadened emission and absorption profiles. This is realized in the framework of integrated data analysis which applies Bayesian probability theory for joint analysis of the electron density and temperature with data of different independent and complementary diagnostics. The method reveals that in regimes with improved confinement ('High-confinement modes' (H-modes)) the edge gradient of the electron temperature can be several times higher than that of the radiation temperature. Furthermore, the model is able to reproduce the 'shine-through' peak - the observation of increased radiation temperatures at frequencies with cold resonance outside the confined plasma region. This phenomenon is caused by strongly down-shifted radiation of Maxwellian tail electrons located in the H-mode edge region and, therefore, contains valuable information about the electron temperature edge gradient. The accurate knowledge about the edge profiles and gradients of the electron temperature and - including the

  15. Experiments on transient melting of tungsten by ELMs in ASDEX Upgrade

    Czech Academy of Sciences Publication Activity Database

    Krieger, K.; Balden, M.; Coenen, J.W.; Laggner, F.; Matthews, G. F.; Nille, D.; Rohde, V.; Sieglin, B.; Giannone, L.; Göths, B.; Herrmann, A.; de Marné, P.; Pitts, R.A.; Potzel, S.; Vondráček, Petr

    2018-01-01

    Roč. 58, č. 2 (2018), č. článku 026024. ISSN 0029-5515 EU Projects: European Commission(XE) 633053 - EUROfusion Institutional support: RVO:61389021 Keywords : fusion * melting * tungsten * plasma wall interaction * power exhaust Subject RIV: BL - Plasma and Gas Discharge Physics OBOR OECD: Fluids and plasma physics (including surface physics) Impact factor: 3.307, year: 2016 http://iopscience.iop.org/article/10.1088/1741-4326/aa9a05

  16. UPGRADES

    CERN Multimedia

    D. Contardo and J. Spalding

    2013-01-01

    The three post-LS1 Phase 1 Upgrade projects (the L1-Trigger, Pixel Tracker, and HCAL) are all making excellent progress and are transitioning from the prototype to the execution phase. Meanwhile plans are developing for Phase 2, a major Upgrade programme targeting the third long shutdown, LS3. News on Phase 1 is included under the respective projects; we only provide a brief summary here. Phase 1 The plan for the L1 Trigger relies on the installation during the present shutdown of optical splitting for the Trigger input signals. This will allow the new Trigger system to be brought online and fully commissioned during beam operation in 2015, while CMS relies on the existing legacy Trigger for physics. Once fully commissioned the experiment can switch over to the new Trigger, which will provide greatly improved performance at high event pile-up, by 2016. System tests of the splitter system, and of the new architecture of the calorimeter trigger were very successful, and the work in LS1 is on-track. Prototype ...

  17. UPGRADES

    CERN Multimedia

    J. Spalding and D. Contardo

    2012-01-01

      The CMS Upgrade Programme consists of four classes of projects: (a) Detector and Systems upgrades which are ongoing and largely (though not entirely) target LS1. (b) Full system upgrades for three projects that are preparing TDRs: Pixels, HCAL and L1 Trigger. The projects target completion by LS2. (c) Infrastructure consolidation and upgrades to improve operational robustness and to support the above projects. (d) Phase 2 replacement of the Tracker and major upgrades of the Trigger and Forward Detectors. For (a) and (c), detailed costing exists and is being integrated into a common reporting system. The schedule milestones for each project will be linked into the overall schedule planning for LS1. For the three TDR projects, the designs have progressed significantly since the Technical Proposal in 2010. Updated detailed cost estimates and schedules will be prepared with the TDRs to form the basis for tracking the projects through completion. To plan the upgrades and the supporting simulati...

  18. UPGRADES

    CERN Multimedia

    J. Butler and J. Nash

    2011-01-01

    Recent progress on the CMS upgrades was summarised, in a workshop held at Fermilab between 7th and 10th November, attended by more than 150 people, many of whom came from Europe and Asia. Important goals of the workshop were to begin to formulate a schedule for the upgrades and to determine project interdependencies. Input was received from all the upgrade working groups and will be combined into a first-pass schedule over the next several weeks. In addition, technical progress on each of the major subtasks was presented and plans for the near-term future were established. Slides from the more than 100 talks are located at: https://indico.cern.ch/conferenceDisplay.py?confId=153564 In the opening plenary session, Frank Zimmermann, of the CERN Beams Department, gave his view of the LHC luminosity evolution. The luminosity will increase faster than we assumed in designing the upgrades. CMS will need to re-evaluate the current upgrade plans and revise them if necessary. CMS Upgrade Physics coordinator...

  19. Experiences upgrading a fluoroscopic system to digital specifications

    International Nuclear Information System (INIS)

    Fox, T.; Fenzl, G.

    1995-01-01

    In 1993, an undertable fluoroscopic system was retrofitted with a Fluorospot HC digital system at the radiological clinic of the Knappschaftskrankenhaus in Puettlingen, Germany. The experiences and possibilities resulting from this digital upgrade are related by the authors, whose narrative is also accompanied by examples of clinical images. The costs involved are also discussed in this article. (orig.)

  20. Upgrade of the ALICE Experiment: Letter of Intent

    CERN Document Server

    Abelev, B; Adamová, D; Aggarwal, M M; Aglieri Rinella, G; Agnello, M; Agostinelli, A; Agrawal, N; Ahammed, Z; Ahmad, N; Ahmad Masoodi, A; Ahmed, I; Ahn, S U; Ahn, S A; Aimo, I; Aiola, S; Ajaz, M; Akindinov, A; Aleksandrov, D; Alessandro, B; Alexandre, D; Alici, A; Alkin, A; Alme, J; Alt, T; Altini, V; Altinpinar, S; Altsybeev, I; Alves Garcia Prado, C; Anderssen, E C; Andrei, C; Andronic, A; Anguelov, V; Anielski, J; Anticic, T; Antinori, F; Antonioli, P; Aphecetche, L; Appelshäuser, H; Arbor, N; Arcelli, S; Armesto, N; Arnaldi, R; Aronsson, T; Arsene, I C; Arslandok, M; Augustinus, A; Averbeck, R; Awes, T C; Azmi, M D; Bach, M; Badalà, A; Baek, Y W; Bagnasco, S; Bailhache, R; Bairathi, V; Bala, R; Baldisseri, A; Baltasar Dos Santos Pedrosa, F; Bán, J; Baral, R C; Barbera, R; Barile, F; Barnaföldi, G G; Barnby, L S; Barret, V; Bartke, J; Basile, M; Bastian Van Beelen, J; Bastid, N; Basu, S; Bathen, B; Batigne, G; Battistin, M; Batyunya, B; Batzing, P C; Baudot, J; Baumann, C; Bearden, I G; Beck, H; Bedda, C; Behera, N K; Belikov, I; Bellini, F; Bellwied, R; Belmont-Moreno, E; Bencedi, G; Benettoni, M; Benotto, F; Beole, S; Berceanu, I; Bercuci, A; Berdnikov, Y; Berenyi, D; Berger, M E; Bertens, R A; Berzano, D; Besson, A; Betev, L; Bhasin, A; Bhati, A K; Bhatti, A; Bhattacharjee, B; Bhom, J; Bianchi, L; Bianchi, N; Bianchin, C; Bielcík, J; Bielcíková, J; Bilandzic, A; Bjelogrlic, S; Blanco, F; Blau, D; Blume, C; Bock, F; Boehmer, F V; Bogdanov, A; Boggild, H; Bogolyubsky, M; Boldizsár, L; Bombara, M; Book, J; Borel, H; Borissov, A; Bornschein, J; Borshchov, V N; Bortolin, C; Bossú, F; Botje, M; Botta, E; Böttger, S; Braun-Munzinger, P; Breitner, T; Broker, T A; Browning, T A; Broz, M; Bruna, E; Bruno, G E; Budnikov, D; Buesching, H; Bufalino, S; Buncic, P; Busch, O; Buthelezi, Z; Caffarri, D; Cai, X; Caines, H; Caliva, A; Calvo Villar, E; Camerini, P; Canoa Roman, V; Carena, F; Carena, W; Cariola, P; Carminati, F; Casanova Díaz, A; Castillo Castellanos, J; Casula, E A R; Catanescu, V; Caudron, T; Cavicchioli, C; Ceballos Sanchez, C; Cepila, J; Cerello, P; Chang, B; Chapeland, S; Charvet, J L; Chattopadhyay, S; Chattopadhyay, S; Cherney, M; Cheshkov, C; Cheynis, B; Chibante Barroso, V; Chinellato, D D; Chochula, P; Chojnacki, M; Choudhury, S; Christakoglou, P; Christensen, C H; Christiansen, P; Chujo, T; Chung, S U; Cicalo, C; Cifarelli, L; Cindolo, F; Claus, G; Cleymans, J; Colamaria, F; Colella, D; Coli, S; Colledani, C; Collu, A; Colocci, M; Conesa Balbastre, G; Conesa del Valle, Z; Connors, M E; Contin, G; Contreras, J G; Cormier, T M; Corrales Morales, Y; Cortese, P; Cortés Maldonado, I; Cosentino, M R; Costa, F; Crochet, P; Cruz Albino, R; Cuautle, E; Cunqueiro, L; Dainese, A; Dang, R; Danu, A; Da Riva, E; Das, D; Das, I; Das, K; Das, S; Dash, A; Dash, S; De, S; Decosse, C; Delagrange, H; Deloff, A; Dénes, E; D'Erasmo, G; de Barros, G O V; De Caro, A; de Cataldo, G; de Cuveland, J; De Falco, A; De Gruttola, D; De Marco, N; De Pasquale, S; De Robertis, G; De Roo, K; de Rooij, R; Diaz Corchero, M A; Dietel, T; Divià, R; Di Bari, D; Di Liberto, S; Di Mauro, A; Di Nezza, P; Djuvsland, o; Dobrin, A; Dobrowolski, T; Domenicis Gimenez, D; Dönigus, B; Dordic, O; Dorheim, S; Dorokhov, A; Doziere, G; Dubey, A K; Dubla, A; Ducroux, L; Dulinski, W; Dupieux, P; Dutta Majumdar, A K; Ehlers III, R J; Elia, D; Engel, H; Erazmus, B; Erdal, H A; Eschweiler, D; Espagnon, B; Estienne, M; Esumi, S; Evans, D; Evdokimov, S; Eyyubova, G; Fabris, D; Faivre, J; Falchieri, D; Fantoni, A; Fasel, M; Fehlker, D; Feldkamp, L; Felea, D; Feliciello, A; Feofilov, G; Ferencei, J; Fernández Téllez, A; Ferreiro, E G; Ferretti, A; Festanti, A; Figiel, J; Figueredo, M A S; Filchagin, S; Finogeev, D; Fionda, F M; Fiore, E M; Fiorenza, G; Floratos, E; Floris, M; Foertsch, S; Foka, P; Fokin, S; Fragiacomo, E; Francescon, A; Franco, M; Frankenfeld, U; Fuchs, U; Furget, C; Fusco Girard, M; Gaardhoje, J J; Gagliardi, M; Gajanana, D; Gallio, M; Gangadharan, D R; Ganoti, P; Garabatos, C; Garcia-Solis, E; Gargiulo, C; Garishvili, I; Gerhard, J; Germain, M; Gheata, A; Gheata, M; Ghidini, B; Ghosh, P; Ghosh, S K; Gianotti, P; Giubilato, P; Giubellino, P; Gladysz-Dziadus, E; Glässel, P; Gomez, R; Gomez Marzoa, M; González-Zamora, P; Gorbunov, S; Görlich, L; Gotovac, S; Graczykowski, L K; Grajcarek, R; Greiner, L C; Grelli, A; Grigoras, A; Grigoras, C; Grigoriev, V; Grigoryan, A; Grigoryan, S; Grinyov, B; Grion, N; Grondin, D; Grosse-Oetringhaus, J F; Grossiord, J -Y; Grosso, R; Guber, F; Guernane, R; Guerzoni, B; Guilbaud, M; Gulbrandsen, K; Gulkanyan, H; Gunji, T; Gupta, A; Gupta, R; H Khan, K; Haake, R; Haaland, o; Hadjidakis, C; Haiduc, M; Hamagaki, H; Hamar, G; Hanratty, L D; Hansen, A; Harris, J W; Hartmann, H; Harton, A; Hatzifotiadou, D; Hayashi, S; Heckel, S T; Heide, M; Helstrup, H; Hennes, E; Herghelegiu, A; Herrera Corral, G; Hess, B A; Hetland, K F; Hicks, B; Hillemanns, H; Himmi, A; Hippolyte, B; Hladky, J; Hristov, P; Huang, M; Hu-Guo, C; Humanic, T J; Hutter, D; Hwang, D S; Igolkin, S; Ijzermans, P; Ilkaev, R; Ilkiv, I; Inaba, M; Incani, E; Innocenti, G M; Ionita, C; Ippolitov, M; Irfan, M; Ivanov, M; Ivanov, V; Ivanytskyi, O; Jacholkowski, A; Jadlovsky, J; Jahnke, C; Jang, H J; Janik, M A; Jayarathna, P H S Y; Jena, S; Jimenez Bustamante, R T; Jones, P G; Jung, H; Junique, A; Jusko, A; Kalcher, S; Kalinak, P; Kalweit, A; Kamin, J; Kang, J H; Kaplin, V; Kar, S; Karasu Uysal, A; Karavichev, O; Karavicheva, T; Karpechev, E; Kebschull, U; Keidel, R; Keil, M; Ketzer, B; Khan, M Mohisin; Khan, P; Khan, S A; Khanzadeev, A; Kharlov, Y; Kileng, B; Kim, B; Kim, D; Kim, D W; Kim, D J; Kim, J S; Kim, M; Kim, M; Kim, S; Kim, T; Kirsch, S; Kisel, I; Kiselev, S; Kisiel, A; Kiss, G; Klay, J L; Klein, J; Klein-Bösing, C; Kluge, A; Knichel, M L; Knospe, A G; Kobdaj, C; Kofarago, M; Köhler, M K; Kollegger, T; Kolojvari, A; Kondratiev, V; Kondratyeva, N; Konevskikh, A; Kovalenko, V; Kowalski, M; Kox, S; Koyithatta Meethaleveedu, G; Kral, J; Králik, I; Kramer, F; Kravcáková, A; Krelina, M; Kretz, M; Krivda, M; Krizek, F; Krus, M; Krymov, E B; Kryshen, E; Krzewicki, M; Kucera, V; Kucheriaev, Y; Kugathasan, T; Kuhn, C; Kuijer, P G; Kulakov, I; Kumar, J; Kurashvili, P; Kurepin, A; Kurepin, A B; Kuryakin, A; Kushpil, S; Kushpil, V; Kweon, M J; Kwon, Y; Ladron de Guevara, P; Lagana Fernandes, C; Lakomov, I; Langoy, R; Lara, C; Lardeux, A; Lattuca, A; La Pointe, S L; La Rocca, P; Lea, R; Lee, G R; Legrand, I; Lehnert, J; Lemmon, R C; Lenhardt, M; Lenti, V; Leogrande, E; Leoncino, M; León Monzón, I; Lesenechal, Y; Lévai, P; Li, S; Lien, J; Lietava, R; Lindal, S; Lindenstruth, V; Lippmann, C; Lisa, M A; Listratenko, O M; Ljunggren, H M; Lodato, D F; Loddo, F; Loenne, P I; Loggins, V R; Loginov, V; Lohner, D; Loizides, C; Lopez, X; López Torres, E; Lu, X -G; Luettig, P; Lunardon, M; Luo, J; Luparello, G; Luzzi, C; M Gago, A; M Jacobs, P; Ma, R; Maevskaya, A; Mager, M; Mahapatra, D P; Maire, A; Malaev, M; Maldonado Cervantes, I; Malinina, L; Mal'Kevich, D; Maltsev, N A; Malzacher, P; Mamonov, A; Manceau, L; Manko, V; Manso, F; Manzari, V; Mapelli, A; Marchisone, M; Mares, J; Margagliotti, G V; Margotti, A; Marín, A; Marin Tobon, C A; Markert, C; Marquard, M; Marras, D; Martashvili, I; Martin, N A; Martinengo, P; Martínez, M I; Martínez García, G; Martin Blanco, J; Martynov, Y; Mas, A; Masciocchi, S; Masera, M; Maslov, M; Masoni, A; Massacrier, L; Mastroserio, A; Mattiazzo, S; Matyja, A; Mayer, C; Mazer, J; Mazumder, R; Mazza, G; Mazzoni, M A; Meddi, F; Menchaca-Rocha, A; Mercado Pérez, J; Meres, M; Miake, Y; Mikhaylov, K; Milano, L; Milosevic, J; Mischke, A; Mishra, A N; Miskowiec, D; Mitu, C M; Mlynarz, J; Mohanty, B; Molnar, L; Mongelli, M; Montaño Zetina, L; Montes, E; Morando, M; Moreira De Godoy, D A; Morel, F; Moretto, S; Morreale, A; Morsch, A; Muccifora, V; Mudnic, E; Muhammad Bhopal, F; Muhuri, S; Mukherjee, M; Müller, H; Munhoz, M G; Murray, S; Musa, L; Musinsky, J; Nandi, B K; Nania, R; Nappi, E; Nattrass, C; Nayak, T K; Nazarenko, S; Nedosekin, A; Nicassio, M; Niculescu, M; Nielsen, B S; Nikolaev, S; Nikulin, S; Nikulin, V; Nilsen, B S; Noferini, F; Nomokonov, P; Nooren, G; Nyanin, A; Nystrand, J; Oeschler, H; Oh, S; Oh, S K; Okatan, A; Olah, L; Oleniacz, J; Oliveira Da Silva, A C; Onderwaater, J; Oppedisano, C; Ortiz Velasquez, A; Oskarsson, A; Otwinowski, J; Oyama, K; Pachmayer, Y; Pachr, M; Pagano, P; Paic, G; Painke, F; Pajares, C; Pal, S K; Palmeri, A; Panati, S; Pant, D; Pantano, D; Papikyan, V; Pappalardo, G S; Park, W J; Passfeld, A; Pastore, C; Patalakha, D I; Paticchio, V; Paul, B; Pawlak, T; Peitzmann, T; Pereira Da Costa, H; Pereira De Oliveira Filho, E; Peresunko, D; Pérez Lara, C E; Peryt, W; Pesci, A; Pestov, Y; Petagna, P; Petrácek, V; Petran, M; Petris, M; Petrovici, M; Petta, C; Pham, H; Piano, S; Pikna, M; Pillot, P; Pinazza, O; Pinsky, L; Piyarathna, D B; Ploskon, M; Planinic, M; Pluta, J; Pochybova, S; Podesta-Lerma, P L M; Poghosyan, M G; Pohjoisaho, E H O; Polichtchouk, B; Poljak, N; Pop, A; Porteboeuf-Houssais, S; Porter, J; Pospisil, V; Potukuchi, B; Prasad, S K; Preghenella, R; Prino, F; Protsenko, M A; Pruneau, C A; Pshenichnov, I; Puddu, G; Puggioni, C; Punin, V; Putschke, J; Qvigstad, H; Rachevski, A; Raha, S; Rak, J; Rakotozafindrabe, A; Ramello, L; Raniwala, R; Raniwala, S; Räsänen, S S; Rascanu, B T; Rasson, J E; Rathee, D; Rauf, A W; Razazi, V; Read, K F; Real, J S; Redlich, K; Reed, R J; Rehman, A; Reichelt, P; Reicher, M; Reidt, F; Renfordt, R; Reolon, A R; Reshetin, A; Rettig, F; Revol, J -P; Reygers, K; Riabov, V; Ricci, R A; Richert, T; Richter, M; Riedler, P; Riegler, W; Riggi, F; Rivetti, A; Rocco, E; Rodríguez Cahuantzi, M; Rodriguez Manso, A; Roed, K; Rogochaya, E; Rohni, S; Rohr, D; Röhrich, D; Romita, R; Ronchetti, F; Ronflette, L; Rosnet, P; Rossegger, S; Rossewij, M J; Rossi, A; Roudier, S; Rousset, J; Roy, A; Roy, C; Roy, P; Rubio Montero, A J; Rui, R; Russo, R; Ryabinkin, E; Ryabov, Y; Rybicki, A; Sacchetti, M; Sadovsky, S; Safarík, K; Sahlmuller, B; Sahoo, R; Sahu, P K; Saini, J; Salgado, C A; Salzwedel, J; Sambyal, S; Samsonov, V; Sanchez Castro, X; Sánchez Rodríguez, F J; sándor, L; Sandoval, A; Sano, M; Santagati, G; Santoro, R; Sarkar, D; Scapparone, E; Scarlassara, F; Scharenberg, R P; Schiaua, C; Schicker, R; Schipper, J D; Schmidt, C; Schmidt, H R; Schuchmann, S; Schukraft, J; Schulc, M; Schuster, T; Schutz, Y; Schwarz, K; Schweda, K; Scioli, G; Scomparin, E; Scott, P A; Scott, R; Segato, G; Seger, J E; Selyuzhenkov, I; Senyukhov, S; Seo, J; Serradilla, E; Sevcenco, A; Sgura, I; Shabetai, A; Shabratova, G; Shahoyan, R; Shangaraev, A; Sharma, N; Sharma, S; Shigaki, K; Shtejer, K; Sibiriak, Y; Siddhanta, S; Siemiarczuk, T; Silvermyr, D; Silvestre, C; Simatovic, G; Singaraju, R; Singh, R; Singha, S; Singhal, V; Sinha, B C; Sinha, T; Sitar, B; Sitta, M; Skaali, T B; Skjerdal, K; Smakal, R; Smirnov, N; Snellings, R J M; Snoeys, W; Sogaard, C; Soltz, R; Song, J; Song, M; Sooden, V; Soramel, F; Sorensen, S; Spacek, M; spalek, J; Spiriti, E; Sputowska, I; Spyropoulou-Stassinaki, M; Srivastava, B K; Stachel, J; Stan, I; Stefanek, G; Steinpreis, M; Stenlund, E; Steyn, G; Stiller, J H; Stocco, D; Stolpovskiy, M; Strmen, P; Suaide, A A P; Subieta Vasquez, M A; Sugitate, T; Suire, C; Suleymanov, M; suljic, M; Sultanov, R; sumbera, M; Sun, X; Susa, T; Symons, T J M; Szanto de Toledo, A; Szarka, I; Szczepankiewicz, A; Szymanski, M; Takahashi, J; Tangaro, M A; Tapia Takaki, J D; Tarantola Peloni, A; Tarazona Martinez, A; Tauro, A; Tejeda Muñoz, G; Telesca, A; Terrevoli, C; Ter Minasyan, A; Thäder, J; Thomas, D; Tieulent, R; Timmins, A R; Toia, A; Torii, H; Trubnikov, V; Trzaska, W H; Tsuji, T; Tumkin, A; Turchetta, R; Turrisi, R; Tveter, T S; Tymchuk, I T; Ulery, J; Ullaland, K; Uras, A; Usai, G L; Vajzer, M; Vala, M; Valencia Palomo, L; Valentino, V; Valin, I; Vallero, S; Vande Vyvre, P; Vannucci, L; Van Der Maarel, J; Van Hoorne, J W; van Leeuwen, M; Vargas, A; Varma, R; Vasileiou, M; Vasiliev, A; Vasta, P; Vechernin, V; Veldhoen, M; Velure, A; Venaruzzo, M; Vercellin, E; Vergara Limón, S; Verlaat, B; Vernet, R; Verweij, M; Vickovic, L; Viesti, G; Viinikainen, J; Vilakazi, Z; Villalobos Baillie, O; Vinogradov, A; Vinogradov, L; Vinogradov, Y; Virgili, T; Viyogi, Y P; Vodopyanov, A; Völkl, M A; Voloshin, K; Voloshin, S A; Volpe, G; von Haller, B; Vorobyev, I; Vranic, D; Vrláková, J; Vulpescu, B; Vyushin, A; Wagner, B; Wagner, J; Wagner, V; Wang, M; Wang, Y; Watanabe, D; Weber, M; Wessels, J P; Westerhoff, U; Wiechula, J; Wikne, J; Wilde, M; Wilk, G; Wilkinson, J; Williams, M C S; Windelband, B; Winn, M; Winter, M; Xiang, C; Yaldo, C G; Yamaguchi, Y; Yang, H; Yang, P; Yang, S; Yano, S; Yasnopolskiy, S; Yi, J; Yin, Z; Yoo, I -K; Yushmanov, I; Zaccolo, V; Zach, C; Zaman, A; Zampolli, C; Zaporozhets, S; Zarochentsev, A; Závada, P; Zaviyalov, N; Zbroszczyk, H; Zgura, I S; Zhalov, M; Zhang, F; Zhang, H; Zhang, X; Zhang, Y; Zhao, C; Zherebchevsky, V I; Zhou, D; Zhou, F; Zhou, Y; Zhu, H; Zhu, J; Zhu, X; Zichichi, A; Zimmermann, A; Zinovjev, G; Zoccarato, Y; Zynovyev, M; Zyzak, M; CERN. Geneva. The LHC experiments Committee; LHCC

    2014-01-01

    The long term goal of the ALICE experiment is to provide a precise characterization of the high-density, high-temperature phase of strongly interacting matter. To achieve this goal, high-statistics precision measurement are required. The general upgrade strategy for the ALICE detector is conceived to deal with this challenge with expected Pb-Pb interaction rates of up to 50 kHz aiming at an integrated luminosity of the order of 10 nb^-1. With the proposed timeline, starting the high-rate operation progressively after 2018 shutdown, the goals set up in our upgrade plans should be achieved collecting data until mid-2020's. In this document we present the main physics motivations for running the LHC with heavy ions at high luminosities and discuss the modifications and replacements needed in the ALICE detectors, the online systems and offline system. The schedule, cost estimate and organization of the upgrade programme are presented as well.

  1. UPGRADES

    CERN Document Server

    D. Contardo and J. Spalding

    2013-01-01

    There is very good progress in the execution of the LS1 projects and in launching construction of the Phase 1 upgrades. We focus here on two main achievements since the last CMS Week. The approval of the third Phase 1 TDR The preparation of the L1 Trigger Upgrade Technical Design Report has been a major effort of the collaboration at the beginning of this year, especially to develop supporting Trigger menu and physics performance studies. These studies have demonstrated the efficiency of the upgraded system to ensure low lepton and jet trigger thresholds, leading to a significant increase of the acceptance for the Higgs measurements, in the associated production mode and in the ττ decays, as well as for the stop searches involving multiple jets in the final state. The TDR was submitted to the LHCC in May and approved at the June committee meeting. It is now a public document, completing the series of the three TDRs describing the Phase 1 upgrades, with the new Pixel system and the HCAL rea...

  2. Periodic Thomson scattering diagnostic with 16 spatial channels on ASDEX

    International Nuclear Information System (INIS)

    Meisel, D.; Murmann, H.; Roehr, H.; Steuer, K.H.; Becker, G.; Bosch, H.S.; Brocken, H.; Eberhagen, A.; Fussmann, G.; Gehre, O.; Gernhardt, J.; Gierke, G. v.; Glock, E.; Gruber, O.; Haas, G.; Hofmann, J.; Janeschitz, G.; Karger, F.; Klueber, O.; Kornherr, M.; Lackner, K.; Lenoci, M.; Lisitano, G.; Mast, F.; Mayer, H.M.; McCormick, K.; Mertens, V.; Niedermeyer, H.; Poschenrieder, W.; Rapp, H.; Roth, J.; Schneider, F.; Setzensack, C.; Siller, G.; Soeldner, F.X.; Wagner, F.; Zasche, D.; Izvozchikov, A.; Ryter, F.

    1986-01-01

    The Nd-YAG Periodic Scattering System (PSS) was developped in teamwork with IPF of Stuttgart-University. At first a PSS with only one spatial channel was successfully tested in the ASDEX-Tokamak in 1982. Subsequently an upgraded system with 16 spatial channels was constructed. This new system is capable of measuring Te, Ne-profiles at 17 ms intervals during the entire ASDEX-Tokamak-discharge. The PSS has been working successfully for the last one and a half years as a standard diagnostic method in the ASDEX-Tokamak. This means, that the measurement is being automatically performed during all plasma-discharges. The Te- and Ne-values are stored in the ASDEX-computer and every user has the possibility to get the Te(r, t), Ne(r, t)-data for his own needs. (orig.)

  3. Silicon vertex detector upgrade in the ALPHA experiment

    CERN Document Server

    Amole, C; Ashkezari, M.D; Baquero-Ruiz, M; Bertsche, W; Burrows, C; Butler, E; Capra, A; Cesar, C.L; Chapman, S; Charlton, M; Deller, A; Eriksson, S; Fajans, J; Friesen, T; Fujiwara, M.C; Gill, D.R; Gutierrez, A; Hangst, J.S; Hardy, W.N; Hayden, M.E; Humphries, A.J; Isaac, C.A; Jonsell, S; Kurchaninov, L; Little, A; Madsen, N; McKenna, J.T.K; Menary, S; Napoli, S.C; Nolan, P; Olchanski, K; Olin, A; Povilus, A; Pusa, P; Rasmussen, C.Ø; Robicheaux, F; Sacramento, R.L; Sampson, J.A; Sarid, E; Seddon, D; Silveira, D.M; So, C; Stracka, S; Tharp, T; Thompson, R.I; Thornhill, J; Tooley, M.P; Van Der Werf, D.P; Wells, D

    2013-01-01

    The Silicon Vertex Detector (SVD) is the main diagnostic tool in the ALPHA-experiment. It provides precise spatial and timing information of antiproton (antihydrogen) annihilation events (vertices), and most importantly, the SVD is capable of directly identifying and analysing single annihilation events, thereby forming the basis of ALPHA ' s analysis. This paper describes the ALPHA SVD and its upgrade, installed in the ALPHA ' s new neutral atom trap.

  4. Commissioning Results of the Upgraded Neutralized Drift Compression Experiment

    International Nuclear Information System (INIS)

    Lidia, S.M.; Roy, P.K.; Seidl, P.A.; Waldron, W.L.; Gilson, E.P.

    2009-01-01

    Recent changes to the NDCX beamline offer the promise of higher charge compressed bunches (>15nC), with correspondingly large intensities (>500kW/cm 2 ), delivered to the target plane for ion-beam driven warm dense matter experiments. We report on commissioning results of the upgraded NDCX beamline that includes a new induction bunching module with approximately twice the volt-seconds and greater tuning flexibility, combined with a longer neutralized drift compression channel.

  5. Silicon vertex detector upgrade in the ALPHA experiment

    Energy Technology Data Exchange (ETDEWEB)

    Amole, C. [Department of Physics and Astronomy, York University, Toronto, ON, M3J 1P3 (Canada); Andresen, G.B. [Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C (Denmark); Ashkezari, M.D. [Department of Physics, Simon Fraser University, Burnaby, BC, V5A 1S6 (Canada); Baquero-Ruiz, M. [Department of Physics, University of California at Berkeley, Berkeley, CA 94720-7300 (United States); Bertsche, W. [School of Physics and Astronomy, University of Manchester, M13 9PL Manchester (United Kingdom); The Cockcroft Institute, Daresbury Laboratory, WA4 4AD Warrington (United Kingdom); Burrows, C. [Department of Physics, College of Science, Swansea University, Swansea SA2 8PP (United Kingdom); Butler, E. [Physics Department, CERN, CH-1211 Geneva 23 (Switzerland); Capra, A. [Department of Physics and Astronomy, York University, Toronto, ON, M3J 1P3 (Canada); Cesar, C.L. [Instituto de Física, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-972 (Brazil); Chapman, S. [Department of Physics, University of California at Berkeley, Berkeley, CA 94720-7300 (United States); Charlton, M.; Deller, A.; Eriksson, S. [Department of Physics, College of Science, Swansea University, Swansea SA2 8PP (United Kingdom); Fajans, J. [Department of Physics, University of California at Berkeley, Berkeley, CA 94720-7300 (United States); Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Friesen, T. [Department of Physics and Astronomy, University of Calgary, Calgary, Alberta T2N 1N4 (Canada); Fujiwara, M.C. [Department of Physics and Astronomy, University of Calgary, Calgary, Alberta T2N 1N4 (Canada); TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, V6T 2A3 (Canada); Gill, D.R. [TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, V6T 2A3 (Canada); Gutierrez, A. [Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, V6T 1Z4 (Canada); and others

    2013-12-21

    The Silicon Vertex Detector (SVD) is the main diagnostic tool in the ALPHA-experiment. It provides precise spatial and timing information of antiproton (antihydrogen) annihilation events (vertices), and most importantly, the SVD is capable of directly identifying and analysing single annihilation events, thereby forming the basis of ALPHA's analysis. This paper describes the ALPHA SVD and its upgrade, installed in the ALPHA's new neutral atom trap.

  6. UPGRADES

    CERN Multimedia

    D. Contardo and J. Spalding

    2012-01-01

      Good progress is being made on the projects that will be installed during LS1. CSC chamber production for ME4/2 is progressing at a rate of four chambers per month, with 25 built so far, and the new electronics for ME1/1 is undergoing a pre-production integration testing. For the RPC chambers, gap production is underway with first deliveries to the chamber assembly sites at CERN and Ghent. The third site at Mumbai will begin production next month. For the PMT replacement in the forward hadron calorimeters (HF), the 1728 PMTs are all characterised and ready to be installed. Testing of the electronics boards is going well. Preparations to replace the HPDs in the outer calorimeter (HO) with SiPMs are also on-track. All components are at CERN and burn-in of the new front-end electronics is proceeding. There are three major upgrade projects targeting the period from LS1 through LS2: a new pixel detector, upgraded photo-detectors and electronics for HCAL, and development of a new L1 Trigger. The new ...

  7. UPGRADES

    CERN Multimedia

    Didier Contardo

    2012-01-01

      The CMS Upgrade Programme is making good progress on the LS1 and Phase 1 projects, in the planning for Phase 2. The construction of the ME4/2 muon chambers to be installed during LS1 has started and the two first CSC production chambers have been fully qualified. The three muon groups have recently established a set of milestones towards the completion of their project, that will be integrated in the detailed planning and scheduling for the shutdown work established by Technical Coordination. The project to replace the photo-detectors in the HF and HO calorimeters is also well advanced and at the validation stage. The operation of an HF slice with new multi-anode PMTs and back-end electronics has already been demonstrated in 2012. For the Phase 1 data-taking, as discussed in the Chamonix workshop, it is likely that the LHC performance will exceed the nominal luminosity and pile-up before the second shutdown, still scheduled in 2018. The collaboration is therefore pursuing a strategy to upgrade ...

  8. Investigation of magnetic modes in the ASDEX tokamak

    International Nuclear Information System (INIS)

    Zohm, H.

    1990-10-01

    Properties of MHD-modes in the ASDEX Tokamak have been investigated by application and further development of the MIRNOV-diagnostics, i.e. measurement of magnetic field fluctuations. In addition to evaluation methods supported by models, also a model-independent statistical data analysis makes sense. The very important physics of mode locking, i.e. the slowing-down of rotating modes is examined. An elaborated theoretical model allows an interpretation of experimental results. Especially interesting is the loss of the angular momentum of rotating plasmas by mode locking. Experiments for mode stabilisation and prevention of electric current breakdown are discussed. Additional MHD-processes under different plasma conditions are treated on the fundament of the devloped model ideas. The author shows that the main tokamak plasma is described very well by one-dimensional models with cylindrical geometry, while the boundary zone of the plasma demands a more complex analysis. In the appendix a concept for the investigation of the MHD-activity in ASDEX-Upgrade is discussed. (AH)

  9. The ATLAS SCT: Commissioning experience and SLHC upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Mitrevski, J. [Santa Cruz Institute for Particle Physics, University of California, Santa Cruz, CA 95064 (United States)], E-mail: Jovan.Mitrevski@cern.ch

    2009-06-01

    The ATLAS Semiconductor Tracker (SCT) has been installed, and fully connected to electrical, optical and cooling services. Commissioning has been performed both with calibration data and cosmic ray events. The cosmics were used to align the detector, measure the hit efficiency and set the timing. The SCT is now ready to take data when the LHC turns on this autumn. At the same time, it is clear that the present ATLAS tracker will need to be renewed for projected luminosity upgrade of the LHC, the SLHC. This is mainly driven by occupancy and radiation hardness issues. The new tracker will likely be entirely made of silicon, with the space of the present SCT largely taken up by detectors with much shorter strips. Several large-scale R and D projects on the sensors and module concepts for this upgrade are running, including sensor and module prototyping. We will report upon the commissioning experience from the SCT, use it to extract valuable lessons for future silicon tracker projects, and give an up-to-date overview of the status and results of the R and D efforts for the ATLAS tracker upgrade.

  10. The ATLAS SCT: Commissioning experience and SLHC upgrade

    International Nuclear Information System (INIS)

    Mitrevski, J.

    2009-01-01

    The ATLAS Semiconductor Tracker (SCT) has been installed, and fully connected to electrical, optical and cooling services. Commissioning has been performed both with calibration data and cosmic ray events. The cosmics were used to align the detector, measure the hit efficiency and set the timing. The SCT is now ready to take data when the LHC turns on this autumn. At the same time, it is clear that the present ATLAS tracker will need to be renewed for projected luminosity upgrade of the LHC, the SLHC. This is mainly driven by occupancy and radiation hardness issues. The new tracker will likely be entirely made of silicon, with the space of the present SCT largely taken up by detectors with much shorter strips. Several large-scale R and D projects on the sensors and module concepts for this upgrade are running, including sensor and module prototyping. We will report upon the commissioning experience from the SCT, use it to extract valuable lessons for future silicon tracker projects, and give an up-to-date overview of the status and results of the R and D efforts for the ATLAS tracker upgrade.

  11. UPGRADES

    CERN Multimedia

    D. Contardo and J. Spalding

    2013-01-01

      LS1 and Phase 1 The detector projects targeting LS1 are progressing well, and a fully integrated schedule developed by Technical Coordination includes installation milestones and a detailed work-plan. The first chambers of the RPC system were produced and are being qualified. Production will ramp up this year to a rate of 20 chambers per month. 32 chambers of the CSC system have been fabricated for the ME4/2 CSC stations, and production proceeds at a rate of 4 per month. The new ME1/1 Front-End Board is in production and the off-detector electronics integration tests are ongoing. The new Theta Trigger Boards for the DT readout production is started and the relocation of the Sector Collector boards with new Optical Links as been successfully tested. All the components for the upgrade of the Forward Hadron Calorimeter PMTs have been received at CERN and assemblies are being qualified. The situation is similar for the Hadron Outer Calorimeter new SiPMs and readout modules. Three projects are plan...

  12. Upgrade of the global muon trigger at the CMS experiment

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00282545; Sakulin, Hannes

    2016-09-14

    The Compact Muon Solenoid (CMS) experiment is one of two general purpose detectors at the Large Hadron Collider (LHC) at the particle physics research laboratory in Geneva (CERN). As such it allows a broad array of physics analyses from precision measurements of the standard model of particle physics to searches for exotic new particles. A series of upgrades and maintenance procedures took place in the first shut down from 2013 to 2015. The aim was to prepare the LHC for the collision energy of 13 TeV and further increase its luminosity. During this shut down also upgrades of the CMS experiment were installed.Due to the high rate of collisions at the LHC, it is impossible to record all such events. In order to reduce the event rate to a manageable level, a trigger system is deployed that selects interesting events. At the CMS experiment this system is divided into two levels: A first hardware based system that is optimised for speed and a second that is software based and applies more time consuming and preci...

  13. Gas box control system for Tandem Mirror Experiment-Upgrade

    International Nuclear Information System (INIS)

    Bell, H.H. Jr.; Hunt, A.L.; Clower, C.A. Jr.

    1983-01-01

    The Tandem Mirror Experiment-Upgrade (TMX-U) uses several methods to feed gas (usually deuterium) at different energies into the plasma region of the machine. One is an arrangement of eight high-speed piezo-electric valves mounted on special manifolds (gas box) that feed cold gas directly to the plasma. This paper describes the electronic valve control and data acquisition portions of the gas box, which are controlled by a desk-top computer. Various flow profiles have been developed and stored in the control computer for ready access by the operator. The system uses two modes of operation, one that exercises and characterizes the valves and one that operates the valves with the rest of the experiment. Both the valve control signals and the pressure transducers data are recorded on the diagnostics computer so that they are available for experiment analysis

  14. Upgrade for Phase II of the Gerda experiment

    Science.gov (United States)

    Agostini, M.; Bakalyarov, A. M.; Balata, M.; Barabanov, I.; Baudis, L.; Bauer, C.; Bellotti, E.; Belogurov, S.; Belyaev, S. T.; Benato, G.; Bettini, A.; Bezrukov, L.; Bode, T.; Borowicz, D.; Brudanin, V.; Brugnera, R.; Caldwell, A.; Cattadori, C.; Chernogorov, A.; D'Andrea, V.; Demidova, E. V.; Di Marco, N.; Domula, A.; Doroshkevich, E.; Egorov, V.; Falkenstein, R.; Frodyma, N.; Gangapshev, A.; Garfagnini, A.; Grabmayr, P.; Gurentsov, V.; Gusev, K.; Hakenmüller, J.; Hegai, A.; Heisel, M.; Hemmer, S.; Hiller, R.; Hofmann, W.; Hult, M.; Inzhechik, L. V.; Ioannucci, L.; Janicskó Csáthy, J.; Jochum, J.; Junker, M.; Kazalov, V.; Kermaïdic, Y.; Kihm, T.; Kirpichnikov, I. V.; Kirsch, A.; Kish, A.; Klimenko, A.; Kneißl, R.; Knöpfle, K. T.; Kochetov, O.; Kornoukhov, V. N.; Kuzminov, V. V.; Laubenstein, M.; Lazzaro, A.; Lebedev, V. I.; Lehnert, B.; Lindner, M.; Lippi, I.; Lubashevskiy, A.; Lubsandorzhiev, B.; Lutter, G.; Macolino, C.; Majorovits, B.; Maneschg, W.; Medinaceli, E.; Miloradovic, M.; Mingazheva, R.; Misiaszek, M.; Moseev, P.; Nemchenok, I.; Nisi, S.; Panas, K.; Pandola, L.; Pelczar, K.; Pullia, A.; Ransom, C.; Riboldi, S.; Rumyantseva, N.; Sada, C.; Salamida, F.; Salathe, M.; Schmitt, C.; Schneider, B.; Schönert, S.; Schreiner, J.; Schütz, A.-K.; Schulz, O.; Schwingenheuer, B.; Selivanenko, O.; Shevchik, E.; Shirchenko, M.; Simgen, H.; Smolnikov, A.; Stanco, L.; Vanhoefer, L.; Vasenko, A. A.; Veresnikova, A.; von Sturm, K.; Wagner, V.; Wegmann, A.; Wester, T.; Wiesinger, C.; Wojcik, M.; Yanovich, E.; Zhitnikov, I.; Zhukov, S. V.; Zinatulina, D.; Zsigmond, A. J.; Zuber, K.; Zuzel, G.

    2018-05-01

    The Gerda collaboration is performing a sensitive search for neutrinoless double beta decay of ^{76}Ge at the INFN Laboratori Nazionali del Gran Sasso, Italy. The upgrade of the Gerda experiment from Phase I to Phase II has been concluded in December 2015. The first Phase II data release shows that the goal to suppress the background by one order of magnitude compared to Phase I has been achieved. Gerda is thus the first experiment that will remain "background-free" up to its design exposure (100 kg year). It will reach thereby a half-life sensitivity of more than 10^{26} year within 3 years of data collection. This paper describes in detail the modifications and improvements of the experimental setup for Phase II and discusses the performance of individual detector components.

  15. Visible spectroscopy on ASDEX

    International Nuclear Information System (INIS)

    Hofmann, J.V.

    1991-12-01

    In this report visible spectroscopy and impurity investigations on ASDEX are reviewed and several sets of visible spectra are presented. As a basis for identification of metallic impurity lines during plasma discharges spectra from a stainless steel - Cu arc have been recorded. In a next step a spectrum overview of ASDEX discharges is shown which reveals the dominating role of lines from light impurities like carbon and oxygen throughout the UV and visible range (2000 A ≤ λ ≤ 8000 A). Metallic impurity lines of neutrals or single ionized atoms are observed near localized surfaces. The dramatic effect of impurity reduction by boronization of the vessel walls is demonstrated in a few examples. In extension to some ivesti-gations already published, further diagnostic applications of visible spectroscopy are presented. Finally, the hardware and software system used on ASDEX are described in detail. (orig.)

  16. Experiences with the ASDEX neutralizer plates and construction of water-cooled plates for long-pulse heating

    International Nuclear Information System (INIS)

    Rapp, H.; Niedermeyer, H.; Kornherr, M.

    1987-01-01

    After dismantling of the titanium neutralizer plates inspection yielded satisfactory status of flat areas whereas edges and curved shapes were heavily melted. At the inner plates of the lower divertor strongly focused melting and cutting was found which is caused by fast electrons. These electrons are continuously produced. The production mechanism is not yet clear but runaway processes can be excluded. With long-pulse additional heating of 6 MW/10s as planned for ASDEX in 1987, the total energy delivered to the plasma will increase by a factor of 30. Therefore new water-cooled neutralizer plates have been constructed which consist of a copper-steel compound. The construction principle and the topology of the cooling circuits is presented

  17. Operational experiences and upgradation of waste management facilities Trombay, India

    International Nuclear Information System (INIS)

    Chander, Mahesh; Bodke, S.B.; Bansal, N.K.

    2001-01-01

    Full text: Waste Management Facilities Trombay provide services for the safe management of radioactive wastes generated from the operation of non power sources at Bhabha Atomic Research Centre, India. The paper describes in detail the current operational experience and facility upgradation by way of revamping of existing processes equipment and systems and augmentation of the facility by way of introducing latest processes and technologies to enhance the safety. Radioactive wastes are generated from the operation of research reactors, fuel fabrication, spent fuel reprocessing, research labs. manufacture of sealed sources and labeled compounds. Use of radiation sources in the field of medical, agriculture and industry also leads to generation of assorted solid waste and spent sealed radiation sources which require proper waste management. Waste Management Facilities Trombay comprise of Effluent Treatment Plant (ETP), Decontamination Centre (DC) and Radioactive Solid Waste Management Site (RSMS). Low level radioactive liquid effluents are received at ETP. Plant has 100 M 3 /day treatment capacity. Decontamination of liquid effluents is effected by chemical treatment method using co- precipitation as a process. Plant has 1800 M 3 of storage capacity. Chemical treatment system comprises of clarifloculator, static mixer and chemical feed tanks. Plant has concentrate management facility where chemical sludge is centrifuged to effect volume reduction of more that 15. Thickened sludge is immobilized in cement matrix. Decontamination Centre caters to the need of equipment decontamination from research reactors. Process used is ultrasonic chemical decontamination. Besides this DC provides services for decontamination of protective wears. Radioactive Solid Waste Management Site is responsible for the safe management of solid waste generated at various research reactors, plants, laboratories in Bhabha Atomic Research Centre. Spent sealed radiation sources are also stored

  18. Experiences in controlling the upgrading of TRIGA 2000 Bandung reactor

    International Nuclear Information System (INIS)

    Huda, K.; Wibowo, Y.W.; Suprawhardana, M.S.

    2001-01-01

    TRIGA 2000 Bandung Reactor was established in 1961 for research, education and isotope production purposes. The reactor reached its first criticality in October 1964 and operated at nominal power of 250 kW until 1971. In 1971 the reactor was upgraded to the power level of 1000 kW. In order to raise the capacity of isotope production, the reactor has been upgraded again to the power level of 2000 kW. During the modification of the reactor, the Center for Research and Development of Nuclear Techniques (CRDNT) was management of the reactor as it faced many problems, either technical or non-technical ones. This caused the upgrading activities to take a long time. At this time, the reactor upgrading has almost finished, and the nuclear commissioning is going on. Several aspects and problems associated with the upgrading process have been reviewed and the results are discussed in the present paper. (author)

  19. Experience of upgrading existing Russian designed nuclear plants

    International Nuclear Information System (INIS)

    Yanev, P.I.; Facer, R.I.

    1993-01-01

    From the reviewed experiences of upgrading existing Russian designed nuclear plants both of WWER and RBMK type the conclusions drawn are as follows. For the countries operating Russian designed plants it is necessary to adopt a pragmatic approach where all changes must be demonstrated to improve the safety of the plant and safety must be demonstrably improving. Care must be taken to avoid the pitfalls of excessive regulatory demands which are not satisfied and the development of an attitude of disregarding requirements on the basis that they are not enforced. For the lending countries and organizations, it is necessary to ensure that assistance is given to the operating organizations so that the most effective use of funds can be achieved. The experience in the West is that over-regulation and excessive expenditure do not necessarily lead to improved safety. They can lead to significant waste of resources. The use of western technology is recommended but where it is necessary and where it provides the greatest benefit

  20. Noble magnetic barriers in the ASDEX UG tokamak

    Science.gov (United States)

    Ali, Halima; Punjabi, Alkesh; Vazquez, Justin

    2010-02-01

    The second-order perturbation method of creating invariant tori inside chaos in Hamiltonian systems (Ali, H.; Punjabi, A. Plasma Phys. Contr. F. 2007, 49, 1565-1582) is applied to the axially symmetric divertor experiment upgrade (ASDEX UG) tokamak to build noble irrational magnetic barriers inside chaos created by resonant magnetic perturbations (m, n)=(3, 2)+(4, 3), with m and n the poloidal and toroidal mode numbers of the Fourier expansion of the magnetic perturbation. The radial dependence of the Fourier modes is ignored. The modes are considered to be locked and have the same amplitude δ. A symplectic mathematical mapping in magnetic coordinates is used to integrate magnetic field line trajectories in the ASDEX UG. Tori with noble irrational rotational transform are the last ones to be destroyed by perturbation in Hamiltonian systems. For this reason, noble irrational magnetic barriers are built inside chaos, and the strongest noble irrational barrier is identified. Three candidate locations for the strongest noble barrier in ASDEX UG are selected. All three candidate locations are chosen to be roughly midway between the resonant rational surfaces ψ32 and ψ43. ψ is the magnetic coordinate of the flux surface. The three candidate surfaces are the noble irrational surfaces close to the surface with q value that is a mediant of q=3/2 and 4/3, q value of the physical midpoint of the two resonant surfaces, and the q value of the surface where the islands of the two perturbing modes just overlap. These q values of the candidate surfaces are denoted by q MED, q MID, and q OVERLAP. The strongest noble barrier close to q MED has the continued fraction representation (CFR) [1;2,2,1∞] and exists for δ≤2.6599×10-4; the strongest noble barrier close to q MID has CFR [1;2,2,2,1∞] and exists for δ≤4.6311×10-4; and the strongest noble barrier close to q OVERLAP has CFR [1;2,2,6,2,1∞] and exists for δ≤1.367770×10-4. From these results, the strongest

  1. TMX-U [Tandem Mirror Experiment-Upgrade] tandem-mirror thermal-barrier experiments

    International Nuclear Information System (INIS)

    Simonen, T.C.; Allen, S.L.; Baldwin, D.E.

    1986-01-01

    Thermal-barrier experiments have been carried out in the Tandem Mirror Experiment-Upgrade (TMX-U). Measurements of nonambipolar and ambipolar radial transport show that these transport processes, as well as end losses, can be controlled at modest densities and durations. Central-cell heating methods using ion-cyclotron heating (ICH) and neutral-beam injection have been demonstrated. Potential mesurements with recently developed methods indicate that deep thermal barriers can be established

  2. LLNL Tandem Mirror Experiment (TMX) upgrade vacuum system

    International Nuclear Information System (INIS)

    Pickles, W.L.; Chargin, A.K.; Drake, R.P.

    1981-01-01

    TMX Upgrade is a large, tandem, magnetic-mirror fusion experiment with stringent requirements on base pressure (10 -8 torr), low H reflux from the first walls, and peak gas pressure (5 x 10 -7 torr) due to neutral beam gas during plasma operation. The 225 m 3 vacuum vessel is initially evacuated by turbopumps. Cryopumps provide a continuous sink for gases other than helium, deuterium, and hydrogen. The neutral beam system introduces up to 480 l/s of H or D. The hydrogen isotopes are pumped at very high speed by titanium sublimed onto two cylindrical radially separated stainless steel quilted liners with a total surface area of 540 m 2 . These surfaces (when cooled to about 80 0 K) provide a pumping speed of 6 x 10 7 l/s for hydrogen. The titanium getter system is programmable and is used for heating as well as gettering. The inner plasma liner can be operated at elevated temperatures to enhance migration of gases away from the surfaces close to the plasma. Glow discharge cleaning is part of the pumpdown procedure. The design features are discussed in conjunction with the operating procedures developed to manage the dynamic vacuum conditions

  3. Experiences when employing different alternatives for envelope upgrading

    Directory of Open Access Journals (Sweden)

    Peru Elguezabal Esnarrizaga

    2015-06-01

    Full Text Available The challenges of achieving the 2020 goals in terms of energy savings and improving efficiency are guiding numerous research initiatives looking for more insulated envelopes, dealing with thermal performance of insulation materials and envelope systems. Nevertheless, the envelope integrates within the building and this improvement on the insulation performance has to be properly adopted, taking into account the interrelation of main elements composing the overall system (facade, frame, slabs, openings, partitions etc., as well as side effects originated not only for new erected buildings, but specifically in renovation and retrofitting works. This paper describes real experiences when considering various options for upgrading the facade through the increase of the insulation capacity, starting from external overcladding prefabricated panels and ventilated facades, advancing to more sustainable low carbon systems and ending with even more highly insulated solutions employing aerogels. Lessons from these cases, where energy and hygrothermal assessments have being carried out, demonstrate the influence of the design and construction phases and the relevance of disregarded effects such as minor thermal bridges, uncontrolled craftsmanship on site, and moisture transfer for the different technologies considered. Finally, possible alternatives are provided to overcome some of the detected difficulties, such as combination with non-metallic structural components and building membranes, and being prepared for future challenges and new developments when these isolative elements are combined with other technologies, as for example, renewable energy harvesting devices.  

  4. National Spherical Torus Experiment (NSTX) Center Stack Upgrade

    International Nuclear Information System (INIS)

    Neumeyer, C.; Avasarala, S.; Chrzanowski, J.; Dudek, L.; Fan, H.; Hatcher, H.; Heitzenroeder, P.; Menard, J.; Ono, M.; Ramakrishnan, S.; Titus, P.; Woolley, R.; Zhan, H.

    2009-01-01

    The purpose of the NSTX Center Stack Upgrade project is to expand the NSTX operational space and thereby the physics basis for next-step ST facilities. The plasma aspect ratio (ratio of plasma major to minor radius) of the upgrade is increased to 1.5 from the original value of 1.26, which increases the cross sectional area of the center stack by a factor of ∼ 3 and makes possible higher levels of performance and pulse duration.

  5. Alfven wave heating in ASDEX

    International Nuclear Information System (INIS)

    Besson, G.; Borg, G.G.; Lister, J.B.; Marmillod, Ph.; Braun, F.; Murphy, A.B.; Noterdaeme, J.M.; Ryter, F.; Wesner, F.

    1990-01-01

    An experiment has been completed on ASDEX to study the response of the plasma to Alfven wave heating (AWH). Antenna excitation was provided by the old TCA rf generator with an output power capability of 500 kW. Two poloidal loop antennas were installed at the east and west ends of the tokamak allowing either N=1 or N=2 phasings. Since the largest antenna coupling to the Alfven resonance is provided by the m=1 surface wave, the antenna consisted only of a single element on the low field side, whereas in TCA the antennas are located on the top and the bottom of the torus. The antenna elements consisted of 2 parallel bars of inductance 730 nH and, as in TCA, were left unshielded. A typical antenna circulating current of 2 kA peak at 1.80 MHz was provided for the experiments. (author) 3 refs., 4 figs

  6. Status of the Tandem Mirror Experiment-Upgrade (TMX-U) diagnostic system

    International Nuclear Information System (INIS)

    Coutts, G.W.; Coffield, F.E.; Hornady, R.S.

    1983-01-01

    This paper presents the current status of the Tandem Mirror Experiment-Upgrade (TMX-U) diagnostics system. For the initial instruments active on TMX-U, the expansions or upgrades that have been implemented are outlined. For the newly added systems, more implementation details are presented

  7. Density fluctuations in ohmic Asdex discharges

    International Nuclear Information System (INIS)

    Dodel, G.; Holzhauer, E.

    1989-01-01

    The investigations on the wave-number and frequency spectra of the density fluctuations, occurring in the different operational modes of ASDEX, are summarized. The aim of the experiments is to study the physical nature of fluctuations and their influence on anomalous transport. The scattering system is described. The results reported were obtained using a 100 mW, λ = 119 μm CW CH-30H laser and homodyne detection

  8. LHCb: Fast Readout Control for the upgraded readout architecture of the LHCb experiment at CERN

    CERN Multimedia

    Alessio, F

    2013-01-01

    The LHCb experiment at CERN has proposed an upgrade towards a full 40 MHz readout system in order to run between five and ten times its initial design luminosity with an upgraded LHCb detector. As a consequence, the various LHCb sub-systems in the readout architecture will be upgraded to cope with higher sub-detector occupancies, higher rate, and higher readout load. The new architecture, new functionalities, and the first hardware implementation of a new LHCb Readout Control system (commonly referred to as S-TFC) for the upgraded LHCb experiment is here presented. Our attention is focused in describing solutions for the distribution of clock and timing information to control the entire upgraded readout architecture by profiting of a bidirectional optical network and powerful FPGAs, including a real-time mechanism to synchronize the entire system. Solutions and implementations are presented, together with first results on the simulation and the validation of the system.

  9. TMX-U [Tandem Mirror Experiment-Upgrade]: Final report, Volume 2

    International Nuclear Information System (INIS)

    Porter, G.D.

    1988-01-01

    This paper discusses the plasma control and the physics accomplishments of the Tandem Mirror Experiment-Upgrade. This particular volume discusses fueling, ion heating, Fokker-Planck modeling, plasma stability and technical development. 270 refs

  10. TMX-U [Tandem Mirror Experiment-Upgrade]: Final report, Volume 1

    International Nuclear Information System (INIS)

    Porter, G.D.

    1988-01-01

    This paper discusses the plasma control and the physics accomplishments of the Tandem Mirror Experiment-Upgrade. This particular volume discusses potential measurements, plasma confinement, and hot electron and ion physics. 230 refs

  11. Ion cyclotron resonant heating 2 x 1700 loop antenna for the Tandem Mirror Experiment-Upgrade

    International Nuclear Information System (INIS)

    Brooksby, C.A.; Ferguson, S.W.; Molvik, A.W.; Barter, J.

    1985-01-01

    This paper reviews the mechanical design and improvements that have taken place on the loop type ion cyclotron resonance heating (ICRH) antennas that are located in the center cell region of the Tandem Mirror Experiment-Upgrade (TMX-U)

  12. The H-mode of ASDEX

    International Nuclear Information System (INIS)

    1989-01-01

    The paper is a review of investigations of the H-mode on ASDEX performed since its discovery in 1982. The topics discussed are: (1) the development of the plasma profiles, with steep gradients in the edge region and flat profiles in the bulk plasma, (2) the MHD properties resulting from the profile changes, including an extensive stability analysis, (3) the impurity development, with special emphasis on the MHD aspects and on neoclassical impurity transport effects in quiescent H-phases, and (4) the properties of the edge plasma, including the evidence of three-dimensional distortions at the edge. The part on confinement includes scaling studies and the results of transport analysis. The power threshold of the H-mode is found to depend weakly on the density, but there is probably no dependence on the toroidal field or the current. For the operational range of the H-mode, new results for the limiter H-mode on ASDEX and the development of the H-mode under beam current drive conditions are included. A number of experiments are described which demonstrate the crucial role of the edge electron temperature in the L-H transition. New results of magnetic and density fluctuation studies at the plasma edge within the edge transport barrier are presented. Finally, the findings on ASDEX are compared with results obtained on other machines and are used to test various H-mode theories. (author). 131 refs, 103 figs, 1 tab

  13. Bohunice V-1. Review of safety upgrading and operating experiences

    International Nuclear Information System (INIS)

    Korec, J.; Kuschel, D.

    2000-01-01

    The Bohunice site in the Slovak Republic has two Russian-designed twin-unit nuclear power plants, one equipped with reactors of the WWER 440/230 type, the other with type WWER 440/213 reactors. Two older units (V-1) started commercial operation in late 1978 and 1980 respectively and have been supplying electricity to the national grid since that time without any events that could have degraded plant safety level. In the period prior to 1990 the utility Slovenske Elektrarne (S.E.) performed extensive modifications and upgrades to the original design of the two older units V-1 NPP. Furthermore, significant steps in safety improvement for Bohunice NPP V-1 have been made since 1990. Following the political restructuring of the former Czechoslovakia and the country's new open-door policy towards western organizations, several international expert missions were focused on evaluation of Bohunice NPP safety status level and operational reliability, particularly targeting the two older units. Based on recommendations of individual expert missions and complementary deterministic and probabilistic safety analyses performed by S.E., the Czechoslovak Nuclear Regulatory Authority issued the Resolution No. 5/91 defining 81 measures concerning further safety and reliability improvement of Bohunice V1 .A range of short-term and long-term upgrades was prioritised in terms of importance to plant safety and work to implement these measures commenced in the early nineties. During the 'Small Reconstruction' from 1991 to 1993 some of the short term upgrading measures were realized to eliminate the most serious safety deficits, thus to achieve a significant reduction in core damage frequency and a major improvement in confinement integrity. In this paper and presentation the goals of the gradual reconstruction project, basic engineering, detailed engineering and realization, last major stage of Unit 2 upgrade, as well as final stage of Unit 1 upgrade in early 2000 are presented

  14. The ATLAS SCT: Commissioning Experience and SLHC Upgrade

    OpenAIRE

    Mitrevski, J

    2008-01-01

    The ATLAS Semiconductor Tracker (SCT) has been installed, and fully connected to electrical, optical and cooling services. Commissioning has been performed both with calibration data and cosmic ray events. The cosmics were used to align the detector, measure the hit efficiency and set the timing. The SCT is now ready to take data when the LHC turns on this autumn. At the same time, it is clear that the present ATLAS tracker will need to be renewed for projected luminosity upgrade of the LHC, ...

  15. Forward calorimetry in the upgraded UA1 experiment

    International Nuclear Information System (INIS)

    Alvarez-Taviel, F.J.; Diez-Hedo, F.; Doncel, P.; Marquina, M.A.; Rodrigo, T.; Bacci, C.; Petrolo, E.; Tusi, A.; Ferrando, A.; Givernaud, A.; Rubbia, C.; Vuillemin, V.

    1989-01-01

    The major improvement in the upgraded UA1 calorimetry at the Santi ppS is the general use of ionization chambers filled with tetramethylpentane (TMP) as a detection medium interspersed with uranium plates as absorber. To achieve overall uniformity of detection down to very small angles, an identical solution is proposed for the forward calorimetry. Forward calorimetry is essential for good total and missing energy measurement at high luminosity in view of the increasing rate of multiple collisions. Both designs for forward and very forward calorimeters are presented along with expected resolutions. (orig.)

  16. Experiments on hot-electron ECRH in the Tandem Mirror Experiment-Upgrade

    International Nuclear Information System (INIS)

    Stallard, B.W.

    1983-01-01

    Experiments have begun on the Tandem Mirror Experiment Upgrade (TMX-U) using electron-cyclotron resonant heating (ECRH) to generate the hot electron populations required for thermal barrier operation (Energy E/sub eh/ approx. 50 keV, density n/sub eh/ 12 , and hot-to-cold fraction n/sub eh/n approx. 0.9). For this operation, rf power produced by 28-GHz gyrotrons is injected with extraordinary mode polarization at both fundamental and second harmonic locations. Our initial experiments, which concentrated on startup of the hot electrons, were carried out at low density ( 12 cm - 3 ) where Fokker-Planck calculations predict high heating efficiency when the electron temperature (T/sub e/) is low. Under these conditions, we produced substantial hot electron populations (diamagnetic energy > 400 J, E/sub eh/ in the range of 15 to 50 keV, and n/sub eh//n > 0.5)

  17. Experience in the upgrading of radioactive waste disposal facility 'Ekores'

    International Nuclear Information System (INIS)

    Rozdyalovskaya, L.

    2000-01-01

    The national Belarus radioactive disposal facility 'Ekores' is designed for waste from nuclear applications in industry, medicine and research. Currently 12-20 tons of waste and over 6000 various types spent sources annually come to the 'Ekores'. Total activity in the vaults is evaluated as 352.8 TBq. Approximately 150 000 spent sources disposed of in the vaults and wells have total activity about 1327 TBq. In 1997 the Government initiated a project for the facility reconstruction in order to upgrade radiological safety of the site by creating adequate safety conditions for managing and storage of the waste. The reconstruction project developed by Belarus specialists has been reviewed by IAEA experts. This covers modernising technologies for new coming waste and also that the waste currently disposed in the pits is retrieved, sorted and treated in the same way as the new coming waste

  18. The upgrade of the muon system of the CMS experiment

    CERN Document Server

    Abbrescia, Marcello

    2014-01-01

    The CMS muon system is based on three types of gaseous detectors, RPC, CSC and DT. While operating very well in the present conditions, upgrades are foreseen for each of the subsystems, necessary to cope with the increased pile-up, coming along with higher rates and radiation, during the upcoming periods of data taking.Moreover, an important issue will be to make the system able to perform its delicate task of muon triggering and tracking also in the High Luminosity phase of LHC, foreseen to start after Long Shutdown 3 in 2023 and to last for about 10 years.Studies devoted to asses the system perfomance stability for the future will be presented. In addition, the stategy - which is being developed - to complement the existing system with new detectors, based on GEM or improved RPC technologies, will be shown.

  19. Expected performance of the upgrade ATLAS experiment for HL-LHC

    CERN Document Server

    Liu, Peilian; The ATLAS collaboration

    2018-01-01

    The Large Hadron Collider (LHC) has been successfully delivering proton-proton collision data at the unprecedented center of mass energy of 13 TeV. An upgrade is planned to increase the instantaneous luminosity delivered by the LHC in what is called the HL-LHC, aiming to deliver a total of up 3000/fb to 4000/fb of data per experiment. To cope with the expected data-taking conditions ATLAS is planning major upgrades of the detector. It is now a critical time for these upgrade projects and during the last year and a half, six Technical Design Reports (TDR) were produced by the ATLAS Collaboration. In these TDRs the physics motivation and benefits of such upgrades are discussed together with details on the upgrade project itself. In this contribution we review the expected performance of the upgraded ATLAS detector and the expected reach for physics measurements as well as the discovery potential for new physics that is expected by the end of the HL-LHC data-taking. The performance of object reconstruction under...

  20. Laser performance upgrade for precise ICF experiment in SG-Ⅲ laser facility

    Directory of Open Access Journals (Sweden)

    Wanguo Zheng

    2017-09-01

    Full Text Available The SG-Ⅲ laser facility (SG-Ⅲ is the largest laser driver for inertial confinement fusion (ICF researches in China, which has 48 beamlines and can deliver 180 kJ ultraviolet laser energy in 3 ns. In order to meet the requirements of precise physics experiments, some new functionalities need to be added to SG-Ⅲ and some intrinsic laser performances need upgrade. So at the end of SG-Ⅲ's engineering construction, the 2-year laser performance upgrade project started. This paper will introduce the newly added functionalities and the latest laser performance of SG-Ⅲ. With these function extensions and performance upgrade, SG-Ⅲ is now fully prepared for precise ICF experiments and solidly paves the way towards fusion ignition.

  1. Construction and operational experience of the Tandem Mirror Experiment-Upgrade (TMX-U)

    International Nuclear Information System (INIS)

    Chargin, A.K.; Calderon, M.O.; Moore, T.L.

    1983-01-01

    The Tandem Mirror Experiment-Upgrade (TMX-U) incorporates two new features at Lawrence Livermore National Laboratory (LLNL) tandem mirror program, thermal barriers in the end plugs and injection of the neutral beams at several oblique angles. The thermal barriers isolate the electrons in the end plugs from those in the central cell, making it possible to heat them independently with microwaves. In addition, this innovation produces a large potential gradient in the end plugs with lower magnetic fields and lower neutral-beam energies than would be possible in a conventional tandem mirror device. The TMX-U is also designed to test neutral-beam-injection angles as an experimental parameter. We use angles other than 90 0 to produce a plasma with improved microstability

  2. Upgrading of the LGD cluster at JINR to support DLNP experiments

    Science.gov (United States)

    Bednyakov, I. V.; Dolbilov, A. G.; Ivanov, Yu. P.

    2017-01-01

    Since its construction in 2005, the Computing Cluster of the Dzhelepov Laboratory of Nuclear Problems has been mainly used to perform calculations (data analysis, simulation, etc.) for various scientific collaborations in which DLNP scientists take an active part. The Cluster also serves to train specialists. Much has changed in the past decades, and the necessity has arisen to upgrade the cluster, increasing its power and replacing the outdated equipment to maintain its reliability and modernity. In this work we describe the experience of performing this upgrading, which can be helpful for system administrators to put new equipment for clusters of this type into operation quickly and efficiently.

  3. Development of large size Micromegas detectors for the upgrade of the ATLAS experiments

    CERN Document Server

    Bianco, Michele

    2014-01-01

    The luminosity upgrade of the Large Hadron Collider at CERN f oresees a luminosity increase by a factor 3 compared to the LHC luminosity design value. To c ope with the corresponding rate increase, the Muon System of the ATLAS experiment at CER N needs to be upgraded. In the first station of the high rapidity region, micromegas det ectors have been chosen as the main tracking chambers but will, at the same time, also contribut e to the trigger. We describe the R&D; efforts that led to the construction of the first (1 × 2.4 m 2 ) large micromegas detectors at CERN and outline the next steps towards the construction of the 12 00 m 2 of micromegas detectors for the ATLAS upgrade. The technical solutions, adopted in the c onstruction of the chamber as well as results on the detector performance with cosmic rays are s hown.

  4. Operational experience of the upgraded LHC injection kicker magnets during Run 2 and future plans

    Science.gov (United States)

    Barnes, M. J.; Adraktas, A.; Bregliozzi, G.; Goddard, B.; Ducimetière, L.; Salvant, B.; Sestak, J.; Vega Cid, L.; Weterings, W.; Vallgren, C. Yin

    2017-07-01

    During Run 1 of the LHC, one of the injection kicker magnets caused occasional operational delays due to beam induced heating with high bunch intensity and short bunch lengths. In addition, there were also sporadic issues with vacuum activity and electrical flashover of the injection kickers. An extensive program of studies was launched and significant upgrades were carried out during Long Shutdown 1 (LS 1). These upgrades included a new design of beam screen to reduce both beam coupling impedance of the kicker magnet and the electric field associated with the screen conductors, hence decreasing the probability of electrical breakdown in this region. This paper presents operational experience of the injection kicker magnets during the first years of Run 2 of the LHC, including a discussion of faults and kicker magnet issues that limited LHC operation. In addition, in light of these issues, plans for further upgrades are briefly discussed.

  5. OPERATIONAL EXPERIENCE: UPGRADED MPC AND A SYSTEMS FOR THE RADIOCHEMICAL PLANT OF THE SIBERIAN CHEMICAL COMBINE

    International Nuclear Information System (INIS)

    RODRIGUEZ, C.; GOLOSKOKOV, I.; FISHBONE, L.; GOODEY, K.; LOOMIS, M.; CRAIN, B. JR.; LARSEN, R.

    2003-01-01

    inventory procedures, and destructive and nondestructive assay equipment to perform neutron and gamma measurements on nuclear materials in process or storage. These MPC and A upgrades have been in operation at the SCC Radiochemical Plant for between 2 and 3 years. The operational experience gained by SCC during this period is currently being evaluated by SCC and ''lessons learned'' will be considered both for continued operation of the Radiochemical Plant MPC and A systems and similar MPC and A systems that are currently being planned for other Plant Sites of the SCC

  6. Commissioning and Operational Experience With an Intermediate Upgrade Cryomodule for the CEBAF 12 GeV Upgrade

    International Nuclear Information System (INIS)

    Thomas Powers; Davis, G.; Michael Drury; Christiana Grenoble; Hovater, J.; Lawrence King; Tomasz Plawski; Joseph Preble

    2005-01-01

    Three cryomodules have been designed and built as intermediate prototypes for the CEBAF 12 GeV upgrade. This paper will discuss the commissioning and operational experience with the second of these cryomodules, which was installed and commissioned in the Jefferson Lab 10 kW Free Electron Laser Facility. Within the cryomodule are eight 7-cell, 1497 MHz cavities. It was designed to accelerate 1 mA of beam in excess of 70 MV and to have the same footprint as a standard CEBAF cryomodule. The cryomodule was installed in parallel with the FEL beam line in the spring of 2004 and characterized simultaneous with beam delivery. It was installed in the beam line in the early summer of 2004 and has since been operated as part of an energy recovered linac with 5 mA of beam current and 75 MV accelerating gradient for extended periods of time. Additionally, it was operated at 1 mA of beam current and 80 MV of accelerating gradient for several hours without a trip. In the latter operating mode the beam current was limited by the injector setup

  7. Tritium depth profiling in carbon samples from fusion experiments

    International Nuclear Information System (INIS)

    Friedrich, M.; Pilz, W.; Sun, G.; Behrisch, R.; Garcia-Rosales, C.; Bekris, N.; Penzhorn, R.-D.

    2000-01-01

    Tritium depth profiling by accelerator mass spectrometry has been performed at the Rossendorf 3 MV Tandetron. Tritium particles are counted after the accelerator using a semiconductor detector, while deuterium and other light elements are simultaneously measured with the Faraday cup between the injection magnet and the accelerator. Depth profiles have been measured in carbon samples cut from the first wall tiles of the Garching fusion experiment ASDEX-Upgrade and of the European fusion experiment JET, Culham/UK. Tritium contents in the JET samples were up to six orders higher than in samples from ASDEX-Upgrade. Tritium beam currents from samples with high tritium content were measured partly in the Faraday cup before the accelerator. A dedicated tritium AMS facility with an air-insulated 100 kV tandem accelerator is under construction

  8. Upgrade of the Global Muon Trigger for the Compact Muon Solenoid experiment at CERN

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00356020; Widmann, Eberhard

    The Large Hadron Collider is a large particle accelerator at the CERN research laboratory, designed to provide particle physics experiments with collisions at unprecedented centre-of-mass energies. For its second running period both the number of colliding particles and their collision energy were increased. To cope with these more challenging conditions and maintain the excellent performance seen during the first running period, the Level-1 trigger of the Compact Muon Solenoid experiment --- a sophisticated electronics system designed to filter events in real-time --- was upgraded. This upgrade consisted of the complete replacement of the trigger electronics and a full redesign of the system's architecture. While the calorimeter trigger path now follows a time-multiplexed processing model where the entire trigger data for a collision are received by a single processing board, the muon trigger path was split into regional track finding systems where each newly introduced track finder receives data from all th...

  9. Operational Experience with Radioactive Source Calibration of the CMS Hadron Endcap Calorimeter Wedges with Phase I Upgrade Electronics

    CERN Document Server

    Bilki, Burak

    2017-01-01

    The Phase I Upgrade of the CMS Hadron Endcap Calorimeters consists of new photodetectors and front-end electronics. The upgrade will allow the elimination of the high amplitude noise and drifting response of the Hybrid Photo-Diodes, at the same time enabling the mitigation of the radiation damage of the scintillators and the wavelength shifting fibers with a larger spectral acceptance of the Silicon Photomultipliers. The upgrade will also allow increasing the longitudinal segmentation of the readout to be beneficial for pile-up mitigation and recalibration due to depth-dependent radiation damage. As a realistic operational exercise, the responses of the Hadron Endcap Calorimeter wedges were calibrated with a 60Co radioactive source both with current and upgrade electronics. The exercise provided significant experience towards the full upgrade during the Year End Technical Stop 2017-2018. Here we describe the instrumentation details and the operational experiences related to the sourcing exercise.

  10. Technician support for operation and maintenance of large fusion experiments: the tandem mirror experiment upgrade (TMX-U) approach

    International Nuclear Information System (INIS)

    Mattson, G.E.

    1983-01-01

    As experiments continue to grow in size and complexity, a few technicians will no longer be able to maintain and operate the complete experiment. Specialization is becoming the norm. Subsystems are becoming very large and complex, requiring a great deal of experience and training for technicians to become qualified maintenance/operation personnel. Formal in-house and off-site programs supplement on-the-job training to fulfill the qualification criteria. This paper presents the Tandem Mirror Experiment-Upgrade (TMX-U) approach to manpower staffing, some problems encountered, possible improvements, and safety considerations for the successful operation of a large experimental facility

  11. Low voltage powering of on-detector electronics for HL-LHC experiments upgrades

    CERN Document Server

    Bobillier, Vincent; Vasey, Francois; Karmakar, Sabyasachi; Maity, Manas; Roy, Subhasish; Kundu, Tapas Kumar

    2018-01-01

    All LHC experiments will be upgraded during the next LHC long shutdowns (LS2 and LS3). The increase in resolution and luminosity and the use of more advanced CMOS technology nodes typically implies higher current consumption of the on-detector electronics. In this context, and in view of limiting the cable voltage drop, point-of-load DC-DC converters will be used on detector. This will have a direct impact on the existing powering scheme, implying new AC-DC and/or DC-DC stages as well as changes in the power cabling infrastructure. This paper presents the first results obtained while evaluating different LV powering schemes and distribution layouts for HL-LHC trackers. The precise low voltage power source requirements are being assessed and understood using the CMS tracker upgrade as a use-case.

  12. The Belgian experience on the backfitting and safety upgrading of old operating nuclear power plants

    International Nuclear Information System (INIS)

    Brognon, T.

    1993-01-01

    The paper describes the methodology for backfitting and safety upgrading during the reevaluation of the Belgian NPP's: first generation (Doel-1, Doel-2, Tihange-1) and second generation plants (Doel-3, Doel-4, Tihange-2 and Tihange-3). A list of essential safety subjects and topics is given. The experience has proved the feasibility of a safety upgrading of operating NPP without injury to its availability, the benefit of a close cooperation between owner, engineering company and safety authorities throughout the project. A global approach to solving numerous specific deficiencies along with the optimization of the investments regarding the safety improvement of the NPP is suggested. Further increase of the know-how will be achieved through the present Belgian programme along with similar activities abroad. (R.I.)

  13. Zambia's participation in past CTBTO activities and the upgrading of AS119 and N192: Experiences and the way forward

    International Nuclear Information System (INIS)

    Lombe, D.K.

    2002-01-01

    This presentation briefly describes the Zambian Seisimic Network (ZSN), Zambia's participation in past CTBTO activities and upgrading of AS119 and N192. It goes on to describe various experiences encountered and makes some suggestions for future considerations

  14. Pellet imaging techniques on ASDEX

    International Nuclear Information System (INIS)

    Wurden, G.A.; Buechl, K.; Hofmann, J.; Lang, R.; Loch, R.; Rudyj, A.; Sandmann, W.

    1990-01-01

    As part of a USDOE/ASDEX collaboration, a detailed examination of pellet ablation in ASDEX with a variety of diagnostics has allowed a better understanding of a number of features of hydrogen ice pellet ablation in a plasma. In particular, fast gated photos with an intensified Xybion CCD video camera allow in-situ velocity measurements of the pellet as it penetrates the plasma. With time resolution of typically 100 nanoseconds and exposures every 50 microseconds, the evolution of each pellet in a multi-pellet ASDEX tokamak plasma discharge can be followed. When the pellet cloud track has striations, the light intensity profile through the cloud is hollow (dark near the pellet), whereas at the beginning or near the end of the pellet trajectory the track is typically smooth (without striations) and has a gaussian-peaked light emission profile. New, single pellet Stark broadened D α D β , and D γ spectra, obtained with a tangentially viewing scanning mirror/spectrometer with Reticon array readout, are consistent with cloud densities of 2 x 10 17 cm -3 or higher in the regions of strongest light emission. A spatially resolved array of D α detectors shows that the light variations during the pellet ablation are not caused solely by a modulation of the incoming energy flux as the pellet crosses rational q-surfaces, but instead are a result of a dynamic, non-stationary, ablation process. 20 refs., 4 figs

  15. Circular waveguide systems for electron-cyclotron-resonant heating of the tandem mirror experiment-upgrade

    International Nuclear Information System (INIS)

    Felker, B.; Calderon, M.O.; Chargin, A.K.

    1983-01-01

    Extensive use of electron cyclotron resonant heating (ECRH) in the Tandem Mirror Experiment-Upgrade (TMX-U) requires continuous development of components to improve efficiency, increase reliability, and deliver power to new locations with respect to the plasma. We have used rectangular waveguide components on the experiment and have developed, tested, and installed circular waveguide components. We replaced the rectangular with the circular components because of the greater transmission efficiency and power-handling capability of the circular ones. Design, fabrication, and testing of all components are complete for all systems. In this paper we describe the design criteria for the system

  16. Operational Experience with Radioactive Source Calibration of the CMS Hadron Endcap Calorimeter Wedges with Phase I Upgrade Electronics

    CERN Document Server

    Bilki, Burak

    2017-01-01

    The Phase I Upgrade of the CMS Hadron Endcap Calorimeters consist of new photodetectors (Silicon Photomultipliers in place of Hybrid Photo-Diodes) and front-end electronics (QIE11). The upgrade will allow the elimination of the high amplitude noise and drifting response of the Hybrid Photo-Diodes, at the same time enabling the mitigation of the radiation damage of the scintillators and the wavelength shifting fibers with a larger spectral acceptance of the Silicon Photomultipliers. The upgrade will also allow to increase the longitudinal segmentation of the readout to be beneficial for pile-up mitigation and recalibration due to depth-dependent radiation damage.As a realistic operational exercise, the responses of the Hadron Endcap Calorimeter wedges are being calibrated with a $^{60}$Co radioactive source both with current and upgrade electronics. The exercise will provide a manifestation of the benefits of the upgrade. Here we describe the instrumentation details and the operational experiences related to t...

  17. Tandem-Mirror Experiment-Upgrade neutral pressure measurement diagnostic systems

    International Nuclear Information System (INIS)

    Pickles, W.L.; Allen, S.L.; Hill, D.N.; Hunt, A.L.; Simonen, T.C.

    1985-01-01

    The Tandem-Mirror Experiment-Upgrade (TMX-U) has a large and complex system of Bayard--Alpert, magnetron, and Penning gauges, in addition to mass spectrometers (RGA), all of which measure neutral pressures in the many internal regions of TMX-U. These pressure measurements are used as part of the confinement physics data base as well as for management of the TMX-U vacuum system. Dynamic pressures are modeled by a coupled-volumes simulation code, which includes wall reflux, getter pumping, and plasma pumping

  18. Quality assurance of GEM foils in the framework of the TPC upgrade in the ALICE experiment

    CERN Document Server

    Ozcelik, Melih Arslan

    2016-01-01

    In the framework of the TPC upgrade of the ALICE Experiment, new readout chambers will be installed during the LHC long shutdown 2, which is scheduled to start in July 2018. The current MWPCs (Multi Wire Proportional Chambers) will be replaced by readout chambers consisting of GEM (Gas Electron Multipliers) foils in order to meet the increasing readout rate requirements. QA (Quality Assurance) tests on the GEMs are performed to classify the foils. In this report we present the work done during the CERN Summer Student Programme 2016.

  19. Neutral particle time-of-flight analyzer for the Tandem Mirror Experiment Upgrade (TMX-U)

    International Nuclear Information System (INIS)

    Hibbs, S.M.; Carter, M.R.; Coutts, G.W.

    1985-01-01

    We describe the design and performance of a time-of-flight (ToF) analyzer being built for installation on the east end cell of the Tandem Mirror Experiment Upgrade (TMX-U). Its primary purpose is to measure the velocity distribution of escaping charge exchange neutral particles having energies between 20 and 5000 electron volts (eV). It also enables direct determination of the thermal barrier potential when used in conjunction with the plasma potential diagnostic and the end loss ion spectrometer. In addition, it can measure the velocity distribution of passing ions leaving the central cell and of ions trapped in the thermal barrier

  20. LHCb - SALT, a dedicated readout chip for strip detectors in the LHCb Upgrade experiment

    CERN Multimedia

    Swientek, Krzysztof Piotr

    2015-01-01

    Silicon strip detectors in the upgraded Tracker of LHCb experiment will require a new readout 128-channel ASIC called SALT. It will extract and digitise analogue signals from the sensor, perform digital processing and transmit serial output data. SALT is designed in CMOS 130 nm process and uses a novel architecture comprising of analogue front-end and ultra-low power ($<$0.5 mW) fast (40 MSps) sampling 6-bit ADC in each channel. A prototype of first 8-channel version of SALT chip, comprising all important functionalities, was submitted. Its design and possibly first tests results will be presented.

  1. Comparison of runaway electron generation parameters in small, medium-sized and large tokamaks—A survey of experiments in COMPASS, TCV, ASDEX-Upgrade and JET

    Czech Academy of Sciences Publication Activity Database

    Plyusnin, V.V.; Reux, C.; Kiptily, V.G.; Pautasso, G.; Decker, J.; Papp, G.; Kallenbach, A.; Weinzettl, Vladimír; Mlynář, Jan; Coda, S.; Riccardo, V.; Lomas, P.; Jachmich, S.; Shevelev, A.E.; Alper, B.; Khilkevitch, E.; Martin, Y.; Dux, R.; Fuchs, C.; Duval, B.; Brix, M.; Tardini, G.; Maraschek, M.; Treutterer, W.; Giannone, L.; Mlynek, A.; Ficker, Ondřej; Martin, P.; Gerasimov, S.; Potzel, S.; Papřok, Richard; McCarthy, P.J.; Imríšek, Martin; Boboc, A.; Lackner, K.; Fernandes, A.; Havlíček, Josef; Giacomelli, L.; Vlainić, M.; Nocente, M.; Kruezi, U.

    2018-01-01

    Roč. 58, č. 1 (2018), č. článku 016014. ISSN 0029-5515 R&D Projects: GA MŠk(CZ) LM2015045 EU Projects: European Commission(XE) 633053 - EUROfusion Institutional support: RVO:61389021 Keywords : Tokamak * disruptions * runaway electrons * hard x rays Subject RIV: BL - Plasma and Gas Discharge Physics OBOR OECD: Fluids and plasma physics (including surface physics) Impact factor: 3.307, year: 2016 http://iopscience.iop.org/article/10.1088/1741-4326/aa8f05/meta

  2. Neutral beam power measurements inside the ASDEX torus

    International Nuclear Information System (INIS)

    Zengliang, Y.; Staebler, A.; Vollmer, O.

    1982-11-01

    Neutral beam power measurements inside the ASDEX torus are done with a retractable calorimeter which is only radiation cooled. The calorimeter plate made from Molybdenum is subdivided into nine segments whose increase in energy content due to a shot yields the absorbed beam power. Different models for the backward extrapolation of the measured temperature curves are examined for a series of low energy shots with the result that pure radiation cooling is a valid assumption. Furthermore, a temperature correction to the measured power is derived from these experiments. The evaluation of the shots onto this calorimeter is done by a computer program. The application of this program to a few full power shots shows that a neutral power up to 3.2 MW has been injected into the ASDEX vessel by the two injectors with an overall efficiency of up to 40%. Reionization losses due to the ASDEX stray field are less than 10%; they do not show any dependence upon the pulse length for shots up to 200 ms. (orig.)

  3. Experiences From Developing and Upgrading a Web-Based Surveillance System for Malaria Elimination in Cambodia.

    Science.gov (United States)

    Fu, Clementine; Lopes, Sérgio; Mellor, Steve; Aryal, Siddhi; Sovannaroth, Siv; Roca-Feltrer, Arantxa

    2017-06-14

    Strengthening the surveillance component is key toward achieving country-wide malaria elimination in Cambodia. A Web-based upgraded malaria information system (MIS) was deemed to essentially act as the central component for surveillance strengthening. New functionality (eg, data visualization) and operational (eg, data quality) attributes of the system received particular attention. However, building from the lessons learned in previous systems' developments, other aspects unique to Cambodia were considered to be equally important; for instance, feasibility issues, particularly at the field level (eg, user acceptability at various health levels), and sustainability needs (eg, long-term system flexibility). The Cambodian process of identifying the essential changes and critical attributes for this new information system can provide a model for other countries at various stages of the disease control and elimination continuum. Sharing these experiences not only facilitates the establishment of "best practices" but also accelerates global and regional malaria elimination efforts. In this article, Cambodia's experience in developing and upgrading its MIS to remain responsive to country-specific needs demonstrates the necessity for considering functionality, operationalization, feasibility, and sustainability of an information system in the context of malaria elimination. ©Clementine Fu, Sérgio Lopes, Steve Mellor, Siddhi Aryal, Siv Sovannaroth, Arantxa Roca-Feltrer. Originally published in JMIR Public Health and Surveillance (http://publichealth.jmir.org), 14.06.2017.

  4. Core heat transfer experiment for JRR-3 to be upgraded at 20 MWt, 2

    International Nuclear Information System (INIS)

    Sudo, Yukio; Miyata, Keiichi; Ikawa, Hiromasa; Ohgawara, Masami; Kaminaga, Masanori

    1985-09-01

    Experiments were carried out to investigate the condition of onset of nucleate boiling (ONB) and the departure from nucleate boiling (DNB) heat flux under forced convection in a vertical rectangular channel, both of which take important roles in the core thermal-hydraulic design of the upgraded JRR-3. This report presents the validity and applicability of the correlations proposed for ONB condition and DNB heat flux, based on the analysis of the experimental results. The upgraded JRR-3 is a low-pressure, low-temperature research reactor and the core heat generation is removed by two cooling modes, one is natural circulation under upflow up to 200 kW and the other is forced circulation under downflow up to 20 MW. Therefore, the difference in heat transfer characteristics between upflow and downflow were investigated in the experiments, which were carried out by using a heated channel properly simulating a subchannel of fuel element because the heat transfer characteristics are considered to be strongly dependent on the configuration of flow channel. (author)

  5. Resistive Micromegas for the Muon Spectrometer Upgrade of the ATLAS Experiment

    CERN Document Server

    Iodice, Mauro; The ATLAS collaboration

    2016-01-01

    Large size resistive Micromegas detectors will be employed for the first time in high-energy physics experiments for the Muon Spectrometer upgrade of the ATLAS experiment at CERN. The current innermost stations of the muon endcap system, the Small Wheel, will be upgraded in 2019 to retain the good precision tracking and trigger capabilities in the high background environment expected with the upcoming luminosity increase of the LHC. Along with the small-strip Thin Gap Chambers (sTGC) the “New Small Wheel” will be equipped with eight layers of Micromegas (MM) detectors arranged in multilayers of two quadruplets, for a total of about 1200 m$^2$ detection planes. All quadruplets have trapezoidal shapes with surface areas between 2 and 3 m$^2$. The Micromegas system will provide both trigger and tracking capabilities. In order to achieve a 15% transverse momentum resolution for 1 TeV muons, a challenging mechanical precision is required in the construction for each plane of the assembled modules, with an alig...

  6. Resistive Micromegas for the Muon Spectrometer Upgrade of the ATLAS Experiment

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00215987; The ATLAS collaboration

    2016-01-01

    Large size resistive micromegas detectors (MM) will be employed for the first time in high-energy physics experiments for the Muon Spectrometer upgrade of the ATLAS experiment at CERN. The current innermost stations of the muon endcap system, the Small Wheel, will be upgraded in 2019 to retain the good precision tracking and trigger capabilities in the high background environment expected with the upcoming luminosity increase of the LHC. Along with the small-strip Thin Gap Chambers (sTGC) the ``New Small Wheel'' will be equipped with eight layers of MM detectors arranged in multilayers of two quadruplets, for a total of about 1200 m$^2$ detection planes. All quadruplets have trapezoidal shapes with surface areas between 2 and 3 m$^2$. The MM system will provide both trigger and tracking capabilities. In order to achieve a 15% transverse momentum resolution for 1 TeV muons, a challenging mechanical precision is required in the construction for each plane of the assembled modules, with an alignment of the reado...

  7. Tandem Mirror Experiment Upgrade (TMX-U) overview-recent events

    International Nuclear Information System (INIS)

    Calderon, M.O.; Bell, H.H.

    1985-01-01

    Since its construction and commissioning was completed in the winter of 1981, the Tandem Mirror Experiment Upgrade (TMX-U) has been conducting tandem mirror thermal barrier experiments. The work, following the fall of 1983 when strong plugging with thermal barriers was achieved, has been directed toward controlling radial transport and forming thermal barriers with high density and Beta. This paper describes the overall engineering component of these efforts. Major changes to the machine have included vacuum improvements, changes to the Electron and Ion Cyclotron Resonance Heating systems (ECRH and ICRH), and the installation of a Plasma Potential Control system (PPC) for radial transport reduction. TMX-U operates an extensive diagnostics system that acquires data from 21 types of diagnostic instruments with more than 600 channels, in addition to 246 machine parameters. The changes and additions will be presented. The closing section of this paper will describe the initial study work for a proposed TMX-U octupole configured machine

  8. Micromegas Detectors for the Muon Spectrometer Upgrade of the ATLAS Experiment

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00211509

    2016-01-01

    Large area Micromegas (MM) detectors will be employed for the Muon Spectrometer upgrade of the ATLAS experiment at the LHC. A total surface of about $150m^2$ of the forward regions of the Muon Spectrometer will be equipped with 8 layers of MM modules. Each module covers a surface area of approximately 2 to $3 m^2$ for a total active area of $1200 m^2$. Together with the small- strips Thin Gap Chambers, they will compose the two New Small Wheels, which will replace the innermost stations of the ATLAS Endcap Muon tracking system in the planned 2018/19 shutdown. This upgrade will mantain a low pt threshold for single muons and provides excellent tracking capabilities for the HL-LHC phase. The NSW project requires fully efficient MM chambers with spatial resolution down to $100 \\mu m$, at rate capability up to about $15kHz/cm^2$ and operation in a moderate (highly inhomogeneous) magnetic field up to B=0.3 T. The required tracking capability is provided by the intrinsic spatial resolution combined with a challengi...

  9. Micromegas Detectors for the Muon Spectrometer Upgrade of the ATLAS Experiment

    CERN Document Server

    Bianco, Michele; The ATLAS collaboration

    2015-01-01

    Large area Micromegas (MM) detectors will be employed for the Muon Spectrometer upgrade of the ATLAS experiment at the LHC. A total surface of about 150 m2 of the forward regions of the Muon Spectrometer will be equipped with 8 layers of MM modules. Each module covers a surface area of approximately 2 to 3 m$^{2}$ for a total active area of 1200 m$^{2}$. Together with the small-strips Thin Gap Chambers, they will compose the two New Small Wheels, which will replace the innermost stations of the ATLAS Endcap Muon tracking system in the planned 2018/19 shutdown. This upgrade will maintain a low pt threshold for single muons and provides excellent tracking capabilities for the HL- LHC phase. The NSW project requires fully efficient MM chambers with spatial resolution down to 100 $ \\mu m$, a rate capability up to about 15 kHz/cm$^{2}$ and operation in a moderate (highly inhomogeneous) magnetic field up to B=0.3 T. The required tracking capability is provided by the intrinsic spatial resolution combined with a cha...

  10. Development of a Level-1 Track and Vertex Finder for the Phase II CMS experiment upgrade

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00414391; Shepherd-Themistocleous, Claire

    The High Luminosity (HL-LHC) upgrade to the Large Hadron Collider will operate at an increased instantaneous luminosity, up to seven times the design value, in order to collect an integrated luminosity of $3,000$\\,fb$^{-1}$ in the decade following 2025. Proton bunches at the HL-LHC will cross every $25$\\,ns, producing an average of 140-200 pile-up proton-proton collisions per crossing. A new tracking detector is under development for use by the CMS experiment at the HL-LHC. A crucial requirement of this upgrade is to provide the ability to reconstruct charged particle tracks with transverse momentum above $2$--$3$\\,GeV within $4\\,\\upmu$s to be used in the Level-1 (L1) trigger decision. This thesis presents one of the main proposals for the final L1 Track Finding system, which exploits a fully time-multiplexed architecture based on high-speed FPGA electronics. The developed track finding algorithm makes use of the Hough Transform technique to identify track candidates, followed by a track fitting stage. Sever...

  11. AREVA 10x10 BWR fuel experience feedback and on going upgrading

    International Nuclear Information System (INIS)

    Lippert, Hans Joachim; Rentmeister, Thomas; Garner, Norman; Tandy, Jay; Mollard, Pierre

    2008-01-01

    Established with engineering and manufacturing operations in the US and Europe, AREVA NP has been and is supplying nuclear fuel assemblies and associated core components to boiling water reactors worldwide, representing today more than 63 000 fuel assemblies. The evolution of BWR fuel rod arrays from early 6x6 designs to the 10x10 designs first introduced in the mid 1990's yielded significant improvements in thermal mechanical operating limits, critical power level, cold shutdown margin, discharge burnup, as well as other key operational capabilities. Since first delivered in 1992, ATRIUM T M 1 0 fuel assemblies have now been supplied to a total of 32 BWR plants in the US, Europe, and Asia resulting in an operating experience over 20 000 fuel assemblies. This article presents in detail the operational experience consolidated by these more than 20 000 ATRIUM T M 1 0 BWR assemblies already supplied to utilities. Within the different 10x10 fuel assemblies available, the Fuel Assembly design is chosen and tailored to the operating strategies of each reactor. Among them, the latest versions of ATRIUM T M a re ATRIUM T M 1 0XP and ATRIUM T M 1 0XM fuel assemblies which have been delivered to several utilities worldwide. The article details key aspects of ATRIUM T M 1 0 fuel assemblies in terms of reliability and performance. Special attention is paid to key proven features, ULTRAFLOW T M s pacer grids, the use of part length fuel rods (PLFRs) and their geometrical optimization, water channel and load chain, upgraded features available for inclusion with most advanced designs. Regular upgrading of the product has been made possible thanks to a continuous improvement process with the aim of further upgrading BWR fuel assembly performance and reliability. Regarding thermal mechanical behavior of fuel rods, chromia (Cr2O3) doped fuel pellets, described in Reference 1, well illustrate this improvement strategy to reduce fission gas release, increase power thresholds for PCI

  12. Operating experience of upgraded radio frequency source at 76 MHz coupled to heavy ion RFQ

    International Nuclear Information System (INIS)

    Pande, Manjiri; Shiju, A.; Patel, N.R.; Shrotriya, S.D.; Bhagwat, P.V.

    2015-01-01

    A heavy ion radio frequency quadrupole (RFQ) accelerator has been developed at BARC (BARC). A RF source which was designed and developed at 76 MHz earlier, has been upgraded and coupled to heavy ion RFQ successfully. The DC bias supplies of this source have been replaced with new supplies having high efficiency and well filteration against RF interference (RFI). The driver of main power amplifier has been replaced with indigenously designed and developed unit. The earlier introduced microcontroller based interlock experienced RF noise issues. So, this circuit has been modified with the new circuit. With these modifications, the performance of the RF source was improved. Additionally, a separate low power RF source of around 100 + Watt was designed, developed and integrated with RFQ for its RF conditioning. This paper describes the details of up gradation of technologies implemented and coupling experience of this RF source with heavy ion RFQ. (author)

  13. Small-Strip Thin Gap Chambers for the Muon Spectrometer Upgrade of the ATLAS Experiment

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00221766; The ATLAS collaboration

    2016-01-01

    The ATLAS muon system upgrade to be installed during the LHC long shutdown in 2018/19, the so called New Small Wheel (NSW), is designed to cope with the increased instantaneous luminosity in LHC Run 3. The small-strip Thin Gap Chambers (sTGC) will provide the NSW with fast trigger and high precision tracking. The construction protocol has been validated by test beam experiments on a full-size prototype sTGC detector, showing the performance requirements are met. The intrinsic spatial resolution for a single layer has been found to be about 50$\\mu$m at perpendicular incident angle, and the pads transition region has been measured to be about 4mm.

  14. The magnet power control system for the tandem mirror experiment-upgrade

    International Nuclear Information System (INIS)

    Bell, H.H.

    1983-01-01

    This paper describes the desktop computer/CAMAC based system that controls the power source for the Tandem Mirror Experiment-Upgrade (TMX-U) magnet power system. Presently it contains 42 dc rectifier power supplies connected to 24 magnet coils arranged in 17 circuits. During each shot, the system delivers 22.6 MW dc to the magnets for about 3 s. The system is presently being changed to add six power supplies, two solenoidal throttle coils, and two reverse C-coils. When complete, the delivered power will increase to 36.9 MW. The closed-loop control system usually provides current (and thus, magnetic field) that is within 1% of the requested current. Achieving this accuracy required using grounding, shielding, and isolation methods to reduce noise and related problems

  15. System upgradation for surface mode negative ion beam extraction experiments in ROBIN

    International Nuclear Information System (INIS)

    Pandya, Kaushal; Bansal, Gourab; Soni, Jignesh

    2015-01-01

    ROBIN (Replica Of BATMAN source in India) is a replica of BATMAN source of IPP, Garching. Plasma production (inductively coupled, RF produced plasma), plasma diagnostic (langmuir probe, optical emission spectroscopy), negative ion beam extraction in volume mode with reduced extraction area of 2 cm 2 (4 apertures) using small bench top type power supply (10kV, 400mA), with increase extraction area of 73 cm 2 (146 apertures) and using actual power supplies (Extraction Power Supply System, EPSS (11kV, 35A), and Accelerator Power Supply System, APSS (35kV, 15A)) and beam diagnostic etc have been performed successfully in ROBIN. This paper will describe the details of the system upgradation for surface mode negative ion experiments and its performance in ROBIN

  16. Review of the Tandem Mirror Experiment-Upgrade (TMX-U) machine-parameter-instrumentation system

    International Nuclear Information System (INIS)

    Kane, R.J.; Coffield, F.E.; Coutts, G.W.; Hornady, R.S.

    1983-01-01

    The Tandem Mirror Experiment-Upgrade (TMX-U) machine consists of seven major machine subsystems: magnet system, neutral beam system, microwave heating (ECRH), ion heating (ICRH), gas fueling, stream guns, and vacuum system. Satisfactory performance of these subsystems is necessary to achieve the experimental objectives planned for TMX-U operations. Since the performance quality of the subsystem is important and can greatly affect plasma parameters, a 233-channel instrumentation system has been installed. Data from the instrumentation system are acquired and stored with the plasma diagnostic information. Thus, the details of the machine performance are available during post-shot analysis. This paper describes all the machine-parameter-instrumentation hardware, presents some typical data, and outlines how the data are used

  17. Upgrade of High-Energy X-Ray real-time radioscopy for KROTOS experiment

    Energy Technology Data Exchange (ETDEWEB)

    Estre, N.; Payan, E.; Cassiaut-Louis, N.; Compagnon, F.; Valerian, M.; Mallet, R. [CEA-Cadarache (France)

    2015-07-01

    As part of its R and D programs on severe accidents, in particular on understanding of corium-water interaction, CEA is commissioning an update of the KROTOS experiment at Cadarache. The Xray imaging setup (high energy real-time radioscopy) is upgraded to provide the best performances for the new experimental program. In order to fit the performance needs (faster acquisition, smaller detection limit and higher field of view), two radioscopy setups, with two linear accelerators (linacs 9 MV and 6 MV), are placed in the irradiation cell. Having discussed the expected performances in terms of frequency, detection limit and field-of-view, this article details each stage of both radioscopy chains: principles and technical characteristics. Then, linacs and cameras synchronization (at few hundred Hertz), data flows and storage setups are detailed. Finally, experimental characterizations and performance validations on phantom are presented. (authors)

  18. Applications of small computers for systems control on the Tandem Mirror Experiment-Upgrade

    International Nuclear Information System (INIS)

    Bork, R.G.; Kane, R.J.; Moore, T.L.

    1983-01-01

    Desktop computers operating into a CAMAC-based interface are used to control and monitor the operation of the various subsystems on the Tandem Mirror Experiment-Upgrade (TMX-U) at Lawrence Livermore National Laboratory (LLNL). These systems include: shot sequencer/master timing, neutral beam control (four consoles), magnet power system control, ion-cyclotron resonant heating (ICRH) control, thermocouple monitoring, getter system control, gas fueling system control, and electron-cyclotron resonant heating (ECRH) monitoring. Two additional computers are used to control the TMX-U neutral beam test stand and provide computer-aided repair/test and development of CAMAC modules. These machines are usually programmed in BASIC, but some codes have been interpreted into assembly language to increase speed. Details of the computer interfaces and system complexity are described as well as the evolution of the systems to their present states

  19. Experiences with the upgraded SKP system during refuelling Paks nuclear power plant

    International Nuclear Information System (INIS)

    Baranyai, A.; Hetzmann, A.

    1997-01-01

    In order to control the neutron flux during the refueling period, new measuring chains were developed and put into operation by the experts of KFKI-RegTron Co., Ltd. and the Paks Nuclear Power Plant with the purpose of partially substituting the original Refuelling Neutron Monitoring system (SKP) of WWER-440 reactor units. The modified monitoring system processes the signals of detectors located in channels outside the core. The outputs of measurement amplifiers equipped with up-to-date electronics fit in the original system perfectly. Use of the out-of-core measuring technique confirmed the preliminary expectations: interference sensitivity has decreased, the neutron/gamma ration increased and refueling time has become shorter by one to one-and-a-half day. The paper details the reasons for upgrading, the essence of utilized solutions and the operational experience. (author)

  20. Upgrade of High-Energy X-Ray real-time radioscopy for KROTOS experiment

    International Nuclear Information System (INIS)

    Estre, N.; Payan, E.; Cassiaut-Louis, N.; Compagnon, F.; Valerian, M.; Mallet, R.

    2015-01-01

    As part of its R and D programs on severe accidents, in particular on understanding of corium-water interaction, CEA is commissioning an update of the KROTOS experiment at Cadarache. The Xray imaging setup (high energy real-time radioscopy) is upgraded to provide the best performances for the new experimental program. In order to fit the performance needs (faster acquisition, smaller detection limit and higher field of view), two radioscopy setups, with two linear accelerators (linacs 9 MV and 6 MV), are placed in the irradiation cell. Having discussed the expected performances in terms of frequency, detection limit and field-of-view, this article details each stage of both radioscopy chains: principles and technical characteristics. Then, linacs and cameras synchronization (at few hundred Hertz), data flows and storage setups are detailed. Finally, experimental characterizations and performance validations on phantom are presented. (authors)

  1. Global performance enhancements via pedestal optimisation on ASDEX Upgrade

    NARCIS (Netherlands)

    Dunne, M.G.; Frassinetti, L.; Beurkens, M.N.A.; Cavedon, M.; Fietz, S.; Fischer, R.; Giannone, L.; Huijsmans, G.T.A.; Kurzan, B.; Laggner, F.; McCarhty, P.J.; McDermott, R.M.; Tardini, G.; Viezzer, E.; Willensdorfer, M.; Wolfrum, E.

    2017-01-01

    Results of experimental scans of heating power, plasma shape, and nitrogen content are presented, with a focus on global performance and pedestal alteration. In detailed scans at low triangularity, it is shown that the increase in stored energy due to nitrogen seeding stems from the pedestal. It is

  2. MHD induced fast-ion losses on ASDEX Upgrade

    International Nuclear Information System (INIS)

    GarcIa-Munoz, M.; Fahrbach, H.-U.; Bobkov, V.; Bruedgam, M.; Guenter, S.; Igochine, V.; Lauber, Ph.; Mantsinen, M.J.; Maraschek, M.; Poli, E.; Sassenberg, K.; Tardini, G.; Zohm, H.; Pinches, S.D.; Gobbin, M.; Marrelli, L.; Martin, P.; Piovesan, P.

    2009-01-01

    A detailed knowledge of the interplay between MHD instabilities and energetic particles has been gained from direct measurements of fast-ion losses (FILs). Time-resolved energy and pitch angle measurements of FIL caused by neoclassical tearing modes (NTMs) and toroidicity-induced Alfven eigenmodes (TAEs) have been obtained using a scintillator based FIL detector. The study of FIL due to TAEs has revealed the existence of a new core-localized MHD fluctuation, the Sierpes mode. The Sierpes mode is a non-pure Alfvenic fluctuation which appears in the acoustic branch, dominating the transport of fast-ions in ICRF heated discharges. The internal structure of both TAEs and Sierpes mode has been reconstructed by means of highly resolved multichord soft x-ray measurements. A spatial overlapping of their eigenfunctions leads to a FIL coupling, showing the strong influence that a core-localized fast-ion driven MHD instability may have on the fast-ion transport. We have identified the FIL mechanisms due to NTMs as well as due to TAEs. Drift islands formed by fast-ions in particle phase space are responsible for the loss of NBI fast-ions due to NTMs. In ICRF heated plasmas, a resonance condition fulfilled by the characteristic trapped fast-ion orbit frequencies leads to a phase matching between fast-ion orbit and NTM or TAE magnetic fluctuation. The banana tips of a resonant trapped fast-ion bounce radially due to an E x B drift in the TAE case. The NTM radial bounce of the fast-ion banana tips is caused by the radial component of the perturbed magnetic field lines.

  3. ELM pace making and amelioration at ASDEX upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Lang, P.T.; Gruber, O.; Haas, G.; Horton, L.D.; Kaufmann, M.; Mertens, V.; Neu, R.; Neuhauser, J.; Puetterich, T.; Schneider, W.; Sihler, C.; Sips, A.C.C.; Suttrop, W.; Treutterer, W. [Max-Planck-Institut fuer Plasmaphysik, Euratom Association, Garching (Germany); Bucalossi, J. [Association Euratom-Confederation Suisse, CRPP-EPFL, Lausanne (Switzerland); Kalvin, S.; Kocsis, G. [Association Euratom, KFKI-RMKI, Budapest (Hungary); Mc Carthy, P.J. [University College Cork, Physics Dept., Association Euratom-DCu, Cork (Ireland)

    2004-07-01

    Different techniques were tried to trigger ELMs (edge localized mode): injection of cryogenic solid pellets or a super-sonic molecular gas jet composed of deuterium or magnetic triggering, relying on a fast motion of the plasma column in a spatially asymmetric flux configuration. Our investigations prove externally imposed control techniques can change the ELM frequency. Frequency enhancement can result in amelioration of the single ELMs. Moreover, the approach can maintain plasma operation at a high performance level. Both pellet injection and magnetic triggering have been shown their potential to act as useful control tools. This yields the option to choose eventually the most appropriate technique for a given scenario.

  4. Recent ASDEX Upgrade research in support of ITER and DEMO

    DEFF Research Database (Denmark)

    Zohm, H.; Ahn, J.; Aho-Mantila, L.

    2015-01-01

    to be the decisive element for the L–H power threshold. A physics based scaling of the density at which the minimum PLH occurs indicates that ITER could take advantage of it to initiate H-mode at lower density than that of the final Q = 10 operational point. Core density fluctuation measurements resolved in radius...... and wave number show that an increase of R/LTe introduced by off-axis electron cyclotron resonance heating (ECRH) mainly increases the large scale fluctuations. The radial variation of the fluctuation level is in agreement with simulations using the GENE code. Fast particles are shown to undergo classical...

  5. Tracking in the trigger from the CDF experience to CMS upgrade

    CERN Document Server

    Palla, F

    2007-01-01

    Precise tracking information in the online selection of interesting physics events is extremely beneficial at hadron colliders. The CDF experiment at the Tevatron, has shown for the first time the impact of the tracking in triggers, allowing to achieve unprecedented precision in B-physics measurements. The CMS experiment at LHC will largely make use of tracking information at high level trigger, after the Level-1 acceptance. The increased luminosity of the Super-LHC collider will impose to CMS a drastic revision of the Level-1 trigger strategy, incorporating the tracker information at the first stage of the selection. After a review of the CDF and CMS approaches we will discuss several possible Level-1 tracker based concepts for the upgraded CMS detector at Super-LHC. One approach is based on associative memories, which has already been demonstrated in CDF. It makes use of binary readout in the front end electronics, followed by transfer of the full granularity data off detector using optical links to dedicat...

  6. Viewgraphs presented at the ASDEX/DOE workshop on disruptions in divertor tokamaks

    Energy Technology Data Exchange (ETDEWEB)

    Granetz, R.; Gruber, O.; Zohm, H. [and others

    1994-09-01

    The emphasis of this year`s ASDEX/DOE workshop was on disruptions in diverted tokamaks. The meeting was held here at MIT on 14--15 March. It is particularly appropriate that MIT hosted the workshop this year, since Alcator C-Mod had just recently completed its very first run campaign, and disruptions are one of the key areas of research in our program. There were a total of 14 speakers, with participants from IPP (Garching), CRPP (Lausanne), Culham, General Atomics, PPPL, Sandia, ORNL, the ITER JCT, and MIT. The subjects addressed included statistical analysis of disruption probabilities in ASDEX, modelling of the vertical axisymmetric plasma motion in DIII-D, impact of disruptions on the design of the ITER divertors, modelling of runaway electrons, and TSC calculations of disruption-induced currents and forces in TPX, etc. One item of particular interest to us was the experimental correlation of halo current magnitude with plasma current on ASDEX-Upgrade. The data indicates at least a linear, and possibly even a quadractic dependence. This has important implications for Alcator C-Mod, since it would predict halo currents of order 1 MA or more at full performance. At the conclusion of the talks, an informal discussion of disruption databases was held, primarily for the purpose of helping us develop a useful one for C-Mod.

  7. Viewgraphs presented at the ASDEX/DOE workshop on disruptions in divertor tokamaks

    International Nuclear Information System (INIS)

    Granetz, R.; Gruber, O.; Zohm, H.

    1994-01-01

    The emphasis of this year's ASDEX/DOE workshop was on disruptions in diverted tokamaks. The meeting was held here at MIT on 14--15 March. It is particularly appropriate that MIT hosted the workshop this year, since Alcator C-Mod had just recently completed its very first run campaign, and disruptions are one of the key areas of research in our program. There were a total of 14 speakers, with participants from IPP (Garching), CRPP (Lausanne), Culham, General Atomics, PPPL, Sandia, ORNL, the ITER JCT, and MIT. The subjects addressed included statistical analysis of disruption probabilities in ASDEX, modelling of the vertical axisymmetric plasma motion in DIII-D, impact of disruptions on the design of the ITER divertors, modelling of runaway electrons, and TSC calculations of disruption-induced currents and forces in TPX, etc. One item of particular interest to us was the experimental correlation of halo current magnitude with plasma current on ASDEX-Upgrade. The data indicates at least a linear, and possibly even a quadractic dependence. This has important implications for Alcator C-Mod, since it would predict halo currents of order 1 MA or more at full performance. At the conclusion of the talks, an informal discussion of disruption databases was held, primarily for the purpose of helping us develop a useful one for C-Mod

  8. A megawatt-level 28 GHz heating system for the National Spherical Torus Experiment Upgrade

    Directory of Open Access Journals (Sweden)

    Taylor G.

    2015-01-01

    Full Text Available The National Spherical Torus Experiment Upgrade (NSTX-U will operate at axial toroidal fields of ≤ 1 T and plasma currents, Ip ≤ 2 MA. The development of non-inductive (NI plasmas is a major long-term research goal for NSTX-U. Time dependent numerical simulations of 28 GHz electron cyclotron (EC heating of low density NI start-up plasmas generated by Coaxial Helicity Injection (CHI in NSTX-U predict a significant and rapid increase of the central electron temperature (Te(0 before the plasma becomes overdense. The increased Te(0 will significantly reduce the Ip decay rate of CHI plasmas, allowing the coupling of fast wave heating and neutral beam injection. A megawatt-level, 28 GHz electron heating system is planned for heating NI start-up plasmas in NSTX-U. In addition to EC heating of CHI start-up discharges, this system will be used for electron Bernstein wave (EBW plasma start-up, and eventually for EBW heating and current drive during the Ip flattop.

  9. Hot-electron plasma formation and confinement in the Tandem Mirror Experiment-Upgrade

    International Nuclear Information System (INIS)

    Ress, D.B.

    1988-01-01

    Electron-cyclotron range-of-frequency heating (ECRH) at 28 GHz is used to create a population of mirror-confined hot electrons in the Tandem Mirror Experiment-Upgrade (TMX-U). Generation of a large fraction of such electrons within each end-cell of TMX-U is essential to the formation of the desired electrostatic potential profile of the thermal-barrier tandem mirror. The formation and confinement of the ECRH-generated hot-electron plasma was investigated with a variety of diagnostic instruments, including a novel instrumented limiter probe. The author characterized the spatial structure of the hot-electron plasma. Details of the heating process cause the plasma to separate into two regions: a halo, consisting entirely of energetic electrons, and a core, which is dominated by cooler electrons. The plasma structure forms rapidly under the action of second-harmonic ECRH. Fundamental ECRH, which is typically applied simultaneously, is only weakly absorbed and generally does not create energetic electrons. The ECRH-generated plasma displays several loss mechanisms. Hot electrons in the halo region, with T e ∼ 30 keV, are formed by localized ECRH near the plasma boundary, and are lost through a radial process involving open magnetic-curvature-drift surfaces

  10. Micromegas Detectors for the Muon Spectrometer Upgrade of the ATLAS Experiment

    CERN Document Server

    Iodice, Mauro; The ATLAS collaboration

    2015-01-01

    The Micromegas (MICRO MEsh GAseous Structure) have been proven along the years to be reliable detectors with excellent space resolution and high rate capability. Large area Micromegas will be employed for the first time in high-energy physics for the Muon Spectrometer upgrade of the ATLAS experiment at CERN LHC. A total surface of about 150 m$^2$ of the forward regions of the Muon Spectrometer will be equipped with 8 layers of Micromegas modules. Each module covers a surface from 2 to 3 m$^2$ for a total active area of 1200 m$^2$. Together with the small-strips Thin Gap Chambers, they will compose the two New Small Wheels, which will replace the innermost stations of the ATLAS Endcap Muon tracking system in the 2018/19 shutdown. The breakthroughs and developments of this type of Micro Pattern Gas Detector will be reviewed, along with the path towards the construction of the modules, which will take place in several production sites starting in 2015. An overview of the detector performances obtained in the rec...

  11. Micromegas Detectors for the Muon Spectrometer Upgrade of the ATLAS Experiment

    CERN Document Server

    Iodice, M; The ATLAS collaboration

    2014-01-01

    The Micromegas (MICRO MEsh GAseous Structure) chambers have been proven along the years to be reliable detectors with excellent space resolution and high rate capability. Large area Micromegas will be employed for the first time in high-energy physics for the Muon Spectrometer upgrade of the ATLAS experiment at CERN LHC. A total surface of about 150 m2 of the forward regions of the Muon Spectrometer will be equipped with 8 layers of Micromegas modules. Each module covers a surface from 2 to 3 m2 for a total active area of 1200 m2. Together with the small-strips Thin Gap Chambers, they will compose the two New Small Wheels, which will replace the innermost stations of the ATLAS Endcap Muon tracking system in the 2018/19 shutdown. The principles of operation and recent developments of this type of Micro Pattern Gas Detector will be reviewed, along with our plans towards the construction of the modules, which will take place in several production sites. An overview of the detector performances obtained in the re...

  12. Physics design of a 28 GHz electron heating system for the National Spherical Torus experiment upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, G.; Bertelli, N.; Ellis, R. A.; Gerhardt, S. P.; Hosea, J. C.; Poli, F. [Princeton Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543 (United States); Harvey, R. W. [CompX, Del Mar, California 92014 (United States); Raman, R. [University of Washington, Seattle, Washington 98195 (United States); Smirnov, A. P. [M.V. Lomonosov Moscow State University, Moscow (Russian Federation)

    2014-02-12

    A megawatt-level, 28 GHz electron heating system is being designed to support non-inductive (NI) plasma current (I{sub p}) start-up and local heating and current drive (CD) in H-mode discharges in the National Spherical Torus Experiment Upgrade (NSTX-U). The development of fully NI I{sub p} start-up and ramp-up is an important goal of the NSTXU research program. 28 GHz electron cyclotron (EC) heating is predicted to rapidly increase the central electron temperature (T{sub e}(0)) of low density NI plasmas generated by Coaxial Helicity Injection (CHI). The increased T{sub e}(0) will significantly reduce the I{sub p} decay rate of CHI plasmas, allowing the coupling of fast wave heating and neutral beam injection. Also 28 GHz electron Bernstein wave (EBW) heating and CD can be used during the I{sub p} flat top in NSTX-U discharges when the plasma is overdense. Ray tracing and Fokker-Planck numerical simulation codes have been used to model EC and EBW heating and CD in NSTX-U. This paper presents a pre-conceptual design for the 28 GHz heating system and some of the results from the numerical simulations.

  13. Ion Cyclotron Resonant Heating 2 X 1700 loop antenna for the Tandem Mirror Experiment-Upgrade

    International Nuclear Information System (INIS)

    Brooksby, C.A.; Ferguson, S.W.; Molvik, A.W.; Barter, J.

    1986-01-01

    This paper reviews the mechanical design and improvements that have taken place on the loop type ion cyclotron resonance heating (ICRH) antennas that are located in the center cell region of the Tandem Mirror Experiment-Upgrade (TMX-U). A computer code (JASON) was used to design getter-shielded antenna supports that will hold off very high voltages (83 kV, DC) over a small insulator distance (2.25 inches) in a vacuum of 10/sup -5/ Torr. The authors also added corona shields on the ceramic-to-metal joints of the matching network capacitors. The system now operates reliably with peak radio frequency (RF) voltages of 40 kV at 2-to-4- MHz frequency and power levels up to 200 kW. The authors have just installed a new loop antenna in the east part of the central cell where the slot antenna was located. This antenna uses two of the slot's internal coax lines and the external matching network. The feedthroughs designed by Lawrence Livermore National Laboratory (LLNL) were replaced with two high-voltage RF feedthroughs designed by Oak Ridge National Laboratory (ORNL)

  14. Securing budget for and implementing your significant simulator upgrade: The Fermi experience

    International Nuclear Information System (INIS)

    Crone, B.D.

    2006-01-01

    Detroit Edison has selected CAE to perform a total simulator upgrade (with the exception of the panel hardware and I/O system) of the Fermi 2 station simulator. The upgrade is intended to improve the performance of the simulator (and thus training effectiveness) while reducing associated operating costs by utilizing an industry standard operating platform, software applications, and off the shelf PC based computer hardware. Additionally, the upgrade is intended to provide the ability to conduct classroom presentations through the use of desktop simulators. Because the cost of a total upgrade is considerable, substantial work is necessary to convince site management that such an undertaking is necessary, can be performed efficiently, and that a return on investment is even possible. This effort was compounded by the lingering history of a previous simulator upgrade, which was completed considerably over-budget and beyond the intended Ready for Training date. As of this writing, the Fermi 2 Simulator Upgrade using CAE products is approximately 60% complete. This paper will describe the methods used to procure funding, as well as steps taken following funding approval to keep the project on track for successful completion. (author)

  15. Design and implementation experience of seismic upgrades at Kozloduy and Paks NPPs

    Energy Technology Data Exchange (ETDEWEB)

    Borov, V; Trichkov, V; Alexandrov, A; Jordanov, M [EQE-Bulgaria, Sofia (Bulgaria)

    1995-07-01

    Series of upgrades have been designed and implemented by EQE-Bulgaria at Kozloduy NPP and as a subcontractor of EQE-International - at Paks NPP. Wide variety of facilities have been upgraded, including Electrical Equipment, Control and Instrumentation Equipment, Technological Equipment, Brick Walls and Building Structures. Different design approaches and concepts have been applied in compliance with the specific technological and structural conditions. The effect of the excitation intensity as well as the presence of specific floor response spectra over the upgrading concept and cost is discussed. Specific problems of supporting heavy technological equipment are noted. A practical approach for seismic upgrading of Brick Walls, as well as a tendency for unification of the engineering design is shown. The first completely upgraded Building Structure at Kozloduy NPP is the structure of the Electrical Control Building to the Diesel Generator of the River-bank Pump Station. Specific problems of the implementation of the final upgrading design of the Diesel Generator Building are outlined. (author)

  16. Design and implementation experience of seismic upgrades at Kozloduy and Paks NPPs

    International Nuclear Information System (INIS)

    Borov, V.; Trichkov, V.; Alexandrov, A.; Jordanov, M.

    1995-01-01

    Series of upgrades have been designed and implemented by EQE-Bulgaria at Kozloduy NPP and as a subcontractor of EQE-International - at Paks NPP. Wide variety of facilities have been upgraded, including Electrical Equipment, Control and Instrumentation Equipment, Technological Equipment, Brick Walls and Building Structures. Different design approaches and concepts have been applied in compliance with the specific technological and structural conditions. The effect of the excitation intensity as well as the presence of specific floor response spectra over the upgrading concept and cost is discussed. Specific problems of supporting heavy technological equipment are noted. A practical approach for seismic upgrading of Brick Walls, as well as a tendency for unification of the engineering design is shown. The first completely upgraded Building Structure at Kozloduy NPP is the structure of the Electrical Control Building to the Diesel Generator of the River-bank Pump Station. Specific problems of the implementation of the final upgrading design of the Diesel Generator Building are outlined. (author)

  17. Measurements of radial profiles of ion cyclotron resonance heating on the Tandem Mirror Experiment-Upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Falabella, S.

    1988-05-11

    A small Radial Energy Analyzer (REA) was used on the Tandem Mirror Experiment-Upgrade (TMX-U), at Lawerence Livermore National Laboratory, to investigate the radial profiles of ion temperature, density, and plasma potential during Ion Cyclotron Resonance Heating (ICRH). The probe has been inserted into the central-cell plasma at temperatures of 200 eV and densities of 3 x 10/sup 12/cm/sup /minus 3// without damage to the probe, or major degradation of the plasma. This analyzer has indicated an increase in ion temperature from near 20 eV before ICRH to near 150 eV during ICRH, with about 60 kW of broadcast power. The REA measurements were cross-checked against other diagnostics on TMX-U and found to be consistent. The ion density measurement was compared to the line-density measured by microwave interferometry and found to agree within 10 to 20%. A radial intergral of n/sub i/T/sub i/ as measured by the REA shows good agreement with the diamagnetic loop measurement of plasma energy. The radial density profile is observed to broaden during the RF heating pulses, without inducing additional radial losses in the core plasma. The radial profile of plasma is seen to vary from axially peaked, to nearly flat as the plasma conditions carried over the series of experiments. To relate the increase in ion temperature to power absorbed by the plasma, a power balance as a function of radius was performed. The RF power absorbed is set equal to the sum of the losses during ICRH, minus those without ICRH. This method accounts for more than 70% of the broadcast power using a simple power balance model. The measured radial profile of the RF heating was compared to the calculations of two codes, ANTENA and GARFIELD, to test their effectiveness as predictors of power absorption profiles for TMX-U. 62 refs., 63 figs., 7 tabs.

  18. Measurements of radial profiles of ion cyclotron resonance heating on the Tandem Mirror Experiment-Upgrade

    International Nuclear Information System (INIS)

    Falabella, S.

    1988-01-01

    A small Radial Energy Analyzer (REA) was used on the Tandem Mirror Experiment-Upgrade (TMX-U), at Lawerence Livermore National Laboratory, to investigate the radial profiles of ion temperature, density, and plasma potential during Ion Cyclotron Resonance Heating (ICRH). The probe has been inserted into the central-cell plasma at temperatures of 200 eV and densities of 3 x 10 12 cm/sup /minus 3// without damage to the probe, or major degradation of the plasma. This analyzer has indicated an increase in ion temperature from near 20 eV before ICRH to near 150 eV during ICRH, with about 60 kW of broadcast power. The REA measurements were cross-checked against other diagnostics on TMX-U and found to be consistent. The ion density measurement was compared to the line-density measured by microwave interferometry and found to agree within 10 to 20%. A radial intergral of n/sub i/T/sub i/ as measured by the REA shows good agreement with the diamagnetic loop measurement of plasma energy. The radial density profile is observed to broaden during the RF heating pulses, without inducing additional radial losses in the core plasma. The radial profile of plasma is seen to vary from axially peaked, to nearly flat as the plasma conditions carried over the series of experiments. To relate the increase in ion temperature to power absorbed by the plasma, a power balance as a function of radius was performed. The RF power absorbed is set equal to the sum of the losses during ICRH, minus those without ICRH. This method accounts for more than 70% of the broadcast power using a simple power balance model. The measured radial profile of the RF heating was compared to the calculations of two codes, ANTENA and GARFIELD, to test their effectiveness as predictors of power absorption profiles for TMX-U. 62 refs., 63 figs., 7 tabs

  19. Hot-electron plasma formation and confinement in the tandem mirror experiment-upgrade

    International Nuclear Information System (INIS)

    Ress, D.B.

    1988-06-01

    The tandem mirror experiment-upgrade (TMX-U) at the Lawrence Livermore National Laboratory (LLNL) is the first experiment to investigate the thermal-barrier tandem-mirror concept. One attractive feature of the tandem magnetic mirror as a commercial power reactor is that the fusion reactions occur in an easily accessible center-cell. On the other hand, complicated end-cells are necessary to provide magnetohydrodynamic (MHD) stability and improved particle confinement of the center-cell plasma. In these end-cells, enhanced confinement is achieved with a particular axial potential profile that is formed with electron-cyclotron range-of-frequency heating (ECRF heating, ECRH). By modifying the loss rates of electrons at spatially distinct locations within the end-cells, the ECRH can tailor the plasma potential profile in the desired fashion. Specifically, the thermal-barrier concept requires generation of a population of energetic electrons near the midplane of each end-cell. To be effective, the transverse (to the magnetic field) spatial structure of the hot-electron plasma must be fairly uniform. In this dissertation we characterize the spatial structure of the ECRH-generated plasma, and determine how the structure builds up in time. Furthermore, the plasma should efficiently absorb the ECRF power, and a large fraction of the electrons must be well confined near the end-cell midplane. Therefore, we also examine in detail the ECRH power balance, determining how the ECRF power is absorbed by the plasma, and the processes through which that power is confined and lost. 43 refs., 69 figs., 6 tabs

  20. The High-Luminosity upgrade of the LHC: Physics and Technology Challenges for the Accelerator and the Experiments

    Science.gov (United States)

    Schmidt, Burkhard

    2016-04-01

    In the second phase of the LHC physics program, the accelerator will provide an additional integrated luminosity of about 2500/fb over 10 years of operation to the general purpose detectors ATLAS and CMS. This will substantially enlarge the mass reach in the search for new particles and will also greatly extend the potential to study the properties of the Higgs boson discovered at the LHC in 2012. In order to meet the experimental challenges of unprecedented pp luminosity, the experiments will need to address the aging of the present detectors and to improve the ability to isolate and precisely measure the products of the most interesting collisions. The lectures gave an overview of the physics motivation and described the conceptual designs and the expected performance of the upgrades of the four major experiments, ALICE, ATLAS, CMS and LHCb, along with the plans to develop the appropriate experimental techniques and a brief overview of the accelerator upgrade. Only some key points of the upgrade program of the four major experiments are discussed in this report; more information can be found in the references given at the end.

  1. Turbulence in the SOL of ASDEX and W7-AS

    Energy Technology Data Exchange (ETDEWEB)

    Endler, M [Association Euratom-Max-Planck-Institut fuer Plasmaphysik, Garching (Germany); Giannone, L. [Association Euratom-Max-Planck-Institut fuer Plasmaphysik, Garching (Germany); McCormick, K [Association Euratom-Max-Planck-Institut fuer Plasmaphysik, Garching (Germany); Niedermeyer, H [Association Euratom-Max-Planck-Institut fuer Plasmaphysik, Garching (Germany); Rudyj, A [Association Euratom-Max-Planck-Institut fuer Plasmaphysik, Garching (Germany); Theimer, G [Association Euratom-Max-Planck-Institut fuer Plasmaphysik, Garching (Germany); Tsois, N [Association Euratom-Max-Planck-Institut fuer Plasmaphysik, Garching (Germany); Zoletnik, S [Hungarian Academy of Sciences, Budapest (Hungary). Central Research Inst. for Physics; ASDEX Team; W7-AS Team

    1995-05-01

    Electrostatic fluctuations have been measured in the scrape-off layer of ASDEX and W7-AS by Langmuir probes and by observation of H{sub {alpha}} light and light emitted from a fast Li atom beam with high spatial and temporal resolution. It was demonstrated that these fluctuations contribute a significant, if not dominant, fraction of the anomalous radial particle transport. The basic properties of the fluctuations are the same in both experiments. A model for an instability mechanism specific to the SOL is presented including density, temperature and electric potential fluctuations. From this model mixing length estimates for the radial transport and resulting density and pressure gradients in the SOL are derived and compared to measurements in the mid-plane and in the divertor of ASDEX. In spite of several simplifications in the model a quantitative agreement up to factors of 1-3 and a qualitative agreement for variations of discharge parameters is achieved between the model predictions and the measurements. Data from poloidal multi-pin probe arrays are decomposed into a sum of spatial-temporal ``events`` by means of a fitting procedure. Centres of selected events serve as reference points for the analysis of the dynamics in their surroundings. Averaging shows that positive and negative potential events appear mostly in pairs with the E x B drift in between directed radially outward. (orig.).

  2. X-ray crystal spectrometer upgrade for ITER-like wall experiments at JET

    Energy Technology Data Exchange (ETDEWEB)

    Shumack, A. E., E-mail: amy.shumack@ccfe.ac.uk [JET-EFDA, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); FOM Institute DIFFER, P.O. Box 1207, NL-3430 BE Nieuwegein (Netherlands); Rzadkiewicz, J. [National Centre for Nuclear Research, Andrzeja Sołtana 7, 05-400 Otwock (Poland); Chernyshova, M.; Czarski, T.; Karpinski, L. [Institute of Plasma Physics and Laser Microfusion, Hery 23, 01-497 Warsaw (Poland); Jakubowska, K. [Institute of Plasma Physics and Laser Microfusion, Hery 23, 01-497 Warsaw (Poland); Université Bordeaux, CNRS, CEA, CELIA, UMR 5107, F-33405 Talence (France); Scholz, M. [Institute of Nuclear Physics PAN, ul. Radzikowskiego 152, 31-342 Kraków (Poland); Byszuk, A.; Cieszewski, R.; Kasprowicz, G.; Pozniak, K.; Wojenski, A.; Zabolotny, W. [Institute of Electronic Systems, Warsaw University of Technology, 00-665 Warsaw (Poland); Dominik, W. [Faculty of Physics, Institute of Experimental Physics, Warsaw University, 00-681 Warsaw (Poland); Conway, N. J.; Dalley, S.; Tyrrell, S.; Zastrow, K.-D. [JET-EFDA, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Figueiredo, J. [EFDA-CSU, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Associação EURATOM/IST, Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Av Rovisco Pais, 1049-001 Lisbon (Portugal); and others

    2014-11-15

    The high resolution X-Ray crystal spectrometer at the JET tokamak has been upgraded with the main goal of measuring the tungsten impurity concentration. This is important for understanding impurity accumulation in the plasma after installation of the JET ITER-like wall (main chamber: Be, divertor: W). This contribution provides details of the upgraded spectrometer with a focus on the aspects important for spectral analysis and plasma parameter calculation. In particular, we describe the determination of the spectrometer sensitivity: important for impurity concentration determination.

  3. ATLAS pixel IBL modules construction experience and developments for future upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Gaudiello, A.

    2015-10-01

    The first upgrade of the ATLAS Pixel Detector is the Insertable B-Layer (IBL), installed in May 2014 in the core of ATLAS. Two different silicon sensor technologies, planar n-in-n and 3D, are used. Sensors are connected with the new generation 130 nm IBM CMOS FE-I4 read-out chip via solder bump-bonds. Production quality control tests were set up to verify and rate the performance of the modules before integration into staves. An overview of module design and construction, the quality control results and production yield will be discussed, as well as future developments foreseen for future detector upgrades.

  4. The Phase-1 Upgrade for the Level-1 Muon Barrel Trigger of the ATLAS Experiment at LHC

    CERN Document Server

    Izzo, Vincenzo; The ATLAS collaboration

    2018-01-01

    The Level-1 Muon Barrel Trigger of the ATLAS Experiment at LHC makes use of Resistive Plate Chamber (RPC) detectors. The on-detector trigger electronics modules are able to identify muons with predefined transverse momentum values (pT) by executing a coincidence logic on signals coming from the various detector layers. On-detector trigger boards then transfer trigger data to the off-detector electronics. A complex trigger system processes the incoming data by combining trigger information from the barrel and the endcap regions, and providing the combined muon candidate to the Central Trigger Processor (CTP). For almost a decade, the Level-1 Trigger system operated very well, despite the challenging requirements on trigger efficiency and performance, and the continuously increasing LHC luminosity. In order to cope with these constraints, various upgrades for the full trigger system were already deployed, and others have been designed to be installed in the next years. Most of the upgrades to the trigger system...

  5. DOE FES FY2017 Joint Research Target Fourth Quarter Milestone Report for theNational Spherical Torus Experiment Upgrade.

    Energy Technology Data Exchange (ETDEWEB)

    Soukhanovskii, V. A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-09-13

    A successful high-performance plasma operation with a radiative divertor has been demonstrated on many tokamak devices, however, significant uncertainty remains in accurately modeling detachment thresholds, and in how detachment depends on divertor geometry. Whereas it was originally planned to perform dedicated divertor experiments on the National Spherical Tokamak Upgrade to address critical detachment and divertor geometry questions for this milestone, the experiments were deferred due to technical difficulties. Instead, existing NSTX divertor data was summarized and re-analyzed where applicable, and additional simulations were performed.

  6. Scenario development during commissioning operations on the National Spherical Torus Experiment Upgrade

    Science.gov (United States)

    Battaglia, D. J.; Boyer, M. D.; Gerhardt, S.; Mueller, D.; Myers, C. E.; Guttenfelder, W.; Menard, J. E.; Sabbagh, S. A.; Scotti, F.; Bedoya, F.; Bell, R. E.; Berkery, J. W.; Diallo, A.; Ferraro, N.; Kaye, S. M.; Jaworski, M. A.; LeBlanc, B. P.; Ono, M.; Park, J.-K.; Podesta, M.; Raman, R.; Soukhanovskii, V.; NSTX-U Research, the; Operations; Engineering Team

    2018-04-01

    The National Spherical Torus Experiment Upgrade (NSTX-U) will advance the physics basis required for achieving steady-state, high-beta, and high-confinement conditions in a tokamak by accessing high toroidal fields (1 T) and plasma currents (1.0-2.0 MA) in a low aspect ratio geometry (A  =  1.6-1.8) with flexible auxiliary heating systems (12 MW NBI, 6 MW HHFW). This paper describes the progress in the development of L- and H-mode discharge scenarios and the commissioning of operational tools in the first ten weeks of operation that enable the scientific mission of NSTX-U. Vacuum field calculations completed prior to operations supported the rapid development and optimization of inductive breakdown at different values of ohmic solenoid current. The toroidal magnetic field (B T0  =  0.65 T) exceeded the maximum values achieved on NSTX and novel long-pulse L-mode discharges with regular sawtooth activity exceeded the longest pulses produced on NSTX (t pulse  >  1.8 s). The increased flux of the central solenoid facilitated the development of stationary L-mode discharges over a range of density and plasma current (I p). H-mode discharges achieved similar levels of stored energy, confinement (H98y,2  >  1) and stability (β N/β N-nowall  >  1) compared to NSTX discharges for I p  ⩽  1 MA. High-performance H-mode scenarios require an L-H transition early in the I p ramp-up phase in order to obtain low internal inductance (l i) throughout the discharge, which is conducive to maintaining vertical stability at high elongation (κ  >  2.2) and achieving long periods of MHD quiescent operations. The rapid progress in developing L- and H-mode scenarios in support of the scientific program was enabled by advances in real-time plasma control, efficient error field identification and correction, effective conditioning of the graphite wall and excellent diagnostic availability.

  7. A brief account of Kozloduy 6 full-scope replica control room simulator upgrade experience: An engineering point of view

    International Nuclear Information System (INIS)

    Dinkov, Y.D.

    2006-01-01

    A short excursion throughout Kozloduy NPP history, and Kozloduy 6 Full-Scope Replica Control Room Simulator procurement, is proposed for a reader, which is not familiar with the Kozloduy circumstances. A brief account of five year operation and upgrade experience is presented as seen by the Kozloduy simulator engineering team. During the last five years Kozloduy 6 is going through a complex and expensive modernization programme so Simulator is a subject of a series of changes twice per year. Simulator is used for training six months of the year during spring and autumn most of this time in two shifts daily. Remaining six months during winter and summer are allocated to other simulator uses including five months downtime for hardware reconstruction, software integration, troubleshooting and testing. Quantitative information concerning scope of software and hardware changes is given. Kozloduy NPP simulator engineering team approach toward various upgrade projects is given in an attempt to facilitate a discussion about how a simulator upgrade should be performed. Projects mentioned vary from small to big, in-house or contracted, already completed or planned for future realization

  8. Investigation of the density turbulence in ohmic ASDEX plasmas

    International Nuclear Information System (INIS)

    Dodel, G.; Holtzhauer, E.

    1989-01-01

    A 119 μm homodyne laser scattering experiment is used on ASDEX to investigate wavenumber and frequency of the density fluctuations occuring in the different operational conditions of the machine. The changes of the density turbulence caused by additional heating are of primary interest with regard to a possible correlation to anomalous transport. Therefore, in the current experiment particular emphasis is placed on these investigations. On the other hand it is the ohmic phase which constitutes the least complicated physical situation in a tokamak and is therefore best suited to reveal the basic physical nature of the density turbulence. In the following we present a summary of our findings in the ohmic phase and make an attempt to compare these findings with what would be expected from the simplest model of density-gradient-driven driftwave turbulence saturated at the mixing-length level. (author) 3 refs., 4 figs

  9. Investigation of the density turbulence in ohmic ASDEX plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Dodel, G; Holtzhauer, E [Stuttgart Univ. (Germany, F.R.). Inst. fuer Plasmaforschung; Giannone, L.; Niedermeyer, H [Max-Planck-Institut fuer Plasmaphysik, Garching (Germany, F.R.)

    1989-01-01

    A 119 {mu}m homodyne laser scattering experiment is used on ASDEX to investigate wavenumber and frequency of the density fluctuations occuring in the different operational conditions of the machine. The changes of the density turbulence caused by additional heating are of primary interest with regard to a possible correlation to anomalous transport. Therefore, in the current experiment particular emphasis is placed on these investigations. On the other hand it is the ohmic phase which constitutes the least complicated physical situation in a tokamak and is therefore best suited to reveal the basic physical nature of the density turbulence. In the following we present a summary of our findings in the ohmic phase and make an attempt to compare these findings with what would be expected from the simplest model of density-gradient-driven driftwave turbulence saturated at the mixing-length level. (author) 3 refs., 4 figs.

  10. System upgradation for surface mode negative ion beam extraction experiments in ROBIN

    International Nuclear Information System (INIS)

    Pandya, Kaushal; Bansal, Gourab; Gahlaut, Agrajit; Soni, Jignesh; Yadav, Ratnakar K.; Mahesh, Vuppugalla; Tyagi, Himanshu; Parmar, KanuG.; Mistri, Hiren; Bhagora, Jighesh; Prajapati, Bhavesh; Patel, Kartik; Bhuyan, Manas; Gouswami, Mehul; Bandyopadhyay, Mainak; Chakraborty, Arun K.

    2017-01-01

    Operational commissioning of ROBIN forms an important milestone in the Indian programme on the R&D on negative ion beams. The commissioning activity has been effected in sequence, in synchronisation with the availability of High voltage Power Supply (HVPS) systems and routine operation has now been established in the cesiated, surface mode. Significant efforts have been placed in upgrading the system to initiate the surface mode operation. These include incorporation of a temperature controlled Cesium (Cs) delivery system, spectroscopic diagnostics for detection of Cs lines, installation of plasma grid heating and closed loop warm water circuit for source components heating and Doppler Shift Spectroscopy (DSS) system. The specific design and integration features for these upgrades are discussed and preliminary results obtained from the operation of ROBIN in the surface mode are presented.

  11. A Neutral Beam for the Lithium Tokamak eXperiment Upgrade (LTX-U)

    Science.gov (United States)

    Merino, Enrique; Majeski, Richard; Kaita, Robert; Kozub, Thomas; Boyle, Dennis; Schmitt, John; Smirnov, Artem

    2015-11-01

    Neutral beam injection into tokamaks is a proven method of plasma heating and fueling. In LTX, high confinement discharges have been achieved with low-recycling lithium walls. To further improve plasma performance, a neutral beam (NB) will be installed as part of an upgrade to LTX (LTX-U). The NB will provide core plasma fueling with up to 700 kW of injected power. Requirements for accommodating the NB include the addition of injection and beam-dump ports onto the vessel and enhancement of the vacuum vessel pumping capability. Because the NB can also serve as a source of neutrals for charge-exchange recombination spectroscopy, ``active'' spectroscopic diagnostics will also be developed. An overview of these plans and other improvements for upgrading LTX to LTX-U will be presented. Supported by US DOE contracts DE-AC02-09CH11466 and DE-AC52-07NA27344.

  12. System upgradation for surface mode negative ion beam extraction experiments in ROBIN

    Energy Technology Data Exchange (ETDEWEB)

    Pandya, Kaushal, E-mail: kpandya@ipr.res.in [Institute for Plasma Research, Near Indira Bridge, Bhat, Gandhinagar, 382428, Gujarat (India); Bansal, Gourab; Gahlaut, Agrajit; Soni, Jignesh [Institute for Plasma Research, Near Indira Bridge, Bhat, Gandhinagar, 382428, Gujarat (India); Yadav, Ratnakar K. [ITER-India, Institute for Plasma Research, Gandhinagar, Gujarat (India); Mahesh, Vuppugalla [Institute for Plasma Research, Near Indira Bridge, Bhat, Gandhinagar, 382428, Gujarat (India); Tyagi, Himanshu [ITER-India, Institute for Plasma Research, Gandhinagar, Gujarat (India); Parmar, KanuG.; Mistri, Hiren [Institute for Plasma Research, Near Indira Bridge, Bhat, Gandhinagar, 382428, Gujarat (India); Bhagora, Jighesh [ITER-India, Institute for Plasma Research, Gandhinagar, Gujarat (India); Prajapati, Bhavesh; Patel, Kartik [Institute for Plasma Research, Near Indira Bridge, Bhat, Gandhinagar, 382428, Gujarat (India); Bhuyan, Manas [ITER-India, Institute for Plasma Research, Gandhinagar, Gujarat (India); Gouswami, Mehul [Bhakti Management Services, Gandhinagar, 382007, Gujarat (India); Bandyopadhyay, Mainak [ITER-India, Institute for Plasma Research, Gandhinagar, Gujarat (India); Chakraborty, Arun K. [Institute for Plasma Research, Near Indira Bridge, Bhat, Gandhinagar, 382428, Gujarat (India)

    2017-01-15

    Operational commissioning of ROBIN forms an important milestone in the Indian programme on the R&D on negative ion beams. The commissioning activity has been effected in sequence, in synchronisation with the availability of High voltage Power Supply (HVPS) systems and routine operation has now been established in the cesiated, surface mode. Significant efforts have been placed in upgrading the system to initiate the surface mode operation. These include incorporation of a temperature controlled Cesium (Cs) delivery system, spectroscopic diagnostics for detection of Cs lines, installation of plasma grid heating and closed loop warm water circuit for source components heating and Doppler Shift Spectroscopy (DSS) system. The specific design and integration features for these upgrades are discussed and preliminary results obtained from the operation of ROBIN in the surface mode are presented.

  13. Machine and plasma diagnostic instrumentation systems for the Tandem Mirror Experiment Upgrade

    International Nuclear Information System (INIS)

    Coutts, G.W.; Coffield, F.E.; Lang, D.D.; Hornady, R.S.

    1981-01-01

    To evaluate performance of a second generation Tandem Mirror Machine, an extensive instrumentation system is being designed and installed as part of the major device fabrication. The systems listed will be operational during the start-up phase of the TMX Upgrade machine and provide bench marks for future performance data. In addition to plasma diagnostic instrumentation, machine parameter monitoring systems will be installed prior to machine operation. Simultaneous recording of machine parameters will permit evaluation of plasma parameters sensitive to machine conditions

  14. Upgrade of the data acquisition system for the A2 experiment at MAMI

    Energy Technology Data Exchange (ETDEWEB)

    Neiser, Andreas; Gradl, Wolfgang [Institut fuer Kernphysik, Johann-Joachim-Becher-Weg 45, Mainz (Germany)

    2015-07-01

    The A2 collaboration at the electron accelerator MAMI in Mainz uses energy-tagged photons to produce light mesons off the nucleon. Its current data acquisition system is the major performance bottleneck under typical trigger conditions. Furthermore, the availability of spare parts is limited, which renders the maintainability for the next decade difficult. Thus, an upgraded system is desirable for A2 to achieve the upcoming experimental goals. For this upgrade, an FPGA-based solution using the TRB3 is being considered. The TRB3 is a multi-purpose 4+1 FPGA board, where four peripheral FPGAs communicate with one add-on board each. The central FPGA provides data readout via standard gigabit Ethernet and interconnection to other TRB3s via optical links. The TRB3 collaboration currently provides flexible TDC-in-FPGA firmwares with various discrimination front-ends as well as a 48 channel ADC add-on board with 60 MHz sampling rate and 10 bit resolution. Additionally, an extensive software framework for slow control and readout is available. We present energy and timing measurements with the ADC add-on board at the Crystal Ball NaI(Tl) calorimeter and compare the performance to the currently used COMPASS data acquisition system. Furthermore, we give an outlook on possible feature extraction firmwares and estimate the costs for a complete upgrade of the system.

  15. Experience with the upgraded VERONA-u WWER-440 core monitoring system

    International Nuclear Information System (INIS)

    Lux, I.; Vegh, J.; Adorjan, F.; Buerger, L.

    1994-01-01

    The paper describes the components, functioning and services of the VERONA-u core monitoring system recently installed at Unit 2 and 3 of the Hungarian Paks NPP. The VERONA-u is a totally upgraded and modernized version of the previous VERONA system, in the upgrading project the data-concentrator, the host computer and the operators' displays were replaced by state-of-the-art hardware and software components. Dual hardware redundancy and automatic function recovery actions were introduced in order to ensure high system availability. The man-machine interface has been redesigned completely, applying X Windows as Graphical User Interface. Improved core analysis and power reconstruction methods were introduced, together with a detailed hot-spot monitoring algorithm. A capable archivation module ensures periodic logging of all measured data, change sensitive storage of important signal changes and provides sophisticated post-mortem analysis tools. The upgraded system has been working satisfactorily on Unit 2 for a complete fuel cycle by now, the on-line system response in complex, transient situations is illustrated in the paper. (author). 10 refs, 4 figs

  16. Fusion reaction product diagnostics in ASDEX

    International Nuclear Information System (INIS)

    Bosch, H.S.

    1987-01-01

    A diagnostic method was developed to look for the charged fusion products from the D(D,p)T-reactions in the divertor tokamak ASDEX. With a semi-conductor detector it was possible to evaluate the ion temperature in thermal plasmas from the proton energy spectra as well as from the triton spectra. In lower-hybrid wave heated plasmas non-thermal (fast) ions were observed. These ions create fusion products with a characteristically different energy spectrum. (orig.)

  17. Manufacturing experience and test results of the PS prototype flexible hybrid circuit for the CMS Tracker Upgrade

    CERN Document Server

    Kovacs, Mark Istvan; Gadek, Tomasz; Honma, Alan; Vasey, Francois

    2017-01-01

    The CMS Tracker Phase-2 Upgrade for HL-LHC requires High Density Interconnect (HDI) flexible hybrid circuits to build modules with low mass and high granularity. The hybrids are carbon fibre reinforced flexible circuits with flip-chips and passives. Three different manufacturers produced prototype hybrids for the Pixel-Strip type modules. The first part of the presentation will focus on the design challenges of this state of the art circuit. Afterwards, the difficulties and experience related to the circuit manufacturing and assembly are presented. The description of quality inspection methods with comprehensive test results will lead to the conclusion.

  18. Development of procedures to ensure quality and integrity in Tandem Mirror Experiment-Upgrade (TMX-U) diagnostics systems

    International Nuclear Information System (INIS)

    Coutts, G.W.; Coon, M.L.; Hinz, A.F.; Hornady, R.S.; Lang, D.D.; Lund, N.P.

    1983-01-01

    The diagnostic systems for Tandem Mirror Experiment-Upgrade (TMX-U) have grown from eleven initial systems to more than twenty systems. During operation, diagnostic system modifications are sometimes required to complete experimental objectives. Also, during operations new diagnostic systems are being developed and implemented. To ensure and maintain the quality and integrity of the data signals, a set of plans and systematic actions are being developed. This paper reviews the procedures set in place to maintain the integrity of existing data systems and ensure the performance objectives of new diagnostics being added

  19. Doosan Experience on I and C Upgrade for Operating NPPs: Control Rod Control System and Automatic Seismic Trip System

    International Nuclear Information System (INIS)

    Nam, C.H.; Kim, K.H.; Lee, D.H.

    2012-01-01

    This paper describes DHIC's experience on upgrading 3 coil type control rod control system(CRCS), 4 coil type control element drive mechanism control system(CEDMCS) and automatic seismic trip system(ASTS). Common main feature of the above systems are full duplex system to prevent unwanted trip and mis-operation. 5 CRCS and CEDMCS have been supplied to Kori 1,2, Ulchin 1,2 and Younggwang 3 since 2010 and 7 CEDMCS are contracted to supply Korea Hydro and Nuclear Power Co.(KHNP) site. Also 16 ASTS are supplied and 12 ASTS will be supplied to operating and new NPPs within 3 years. (author)

  20. Experimental and theoretical investigation of density and potential fluctuations in the scrape-off layer of ASDEX

    International Nuclear Information System (INIS)

    Endler, M.; Giannone, L.; Niedermeyer, H.; Rudyj, A.; Theimer, G.

    1993-01-01

    In the divertor tokamak ASDEX density and potential fluctuations in the scrape-off layer were investigated with high temporal and spatial resolution by Langmuir probes and an H α diagnostic. Many results of these measurements were reported and are summarized below. Several of these properties of the fluctuations have also been reported from other experiments. (orig.)

  1. Characteristics of toroidal energy deposition asymmetries in ASDEX

    International Nuclear Information System (INIS)

    Evans, T.E.; Neuhauser, J.; Leuterer, F.; Mueller, E.R.

    1990-01-01

    Large toroidal and poloidal asymmetries with characteristics which are sensitively dependent on q a , the vertical position of the plasma, and the type of additional heating are observed in the energy flow to the ASDEX divertor target plates. The largest asymmetries and total energy depositions are observed during lower hybrid wave injection experiments with approximately 50% of the input energy going to the combined divertor targets and shields. A maximum localized energy density loading of 10 MJ/m 2 is typical under these conditions. Measurements of the asymmetries are consistent with a model in which magnetic islands and ergodicity due to intrinsic magnetic perturbations dominate the energy transpot across the primary magnetic separatrix. The results emphasize the essential role of resonant magnetic perturbations in determining the performance of tokamaks and demonstrate that non-axisymmetric effects caused by small perturbations become increasingly important in determining the transport properties as the injected power is increased. (orig.)

  2. Test beam results for an upgraded forward tagger of the L3 experiment at LEP II

    International Nuclear Information System (INIS)

    Chemarin, M.; Depasse, P.; Fay, J.; Felcini, M.; Fredj, L.; Ille, B.; Nessi-Tedaldi, F.; Susinno, G.F.

    1994-01-01

    We have tested new scintillator modules with silicon photodiode readout for the upgraded Active Lead Rings (ALR) of the L3 detector at LEP II. Results are presented from data recorded in muon and electron test beams with particular emphasis on the light production and collection as a function of the particle impact position on the scintillator modules. The results from the beam test data will be used for the design of the readout and trigger electronics in conjunction with the required ALR performance as an electron tagger and beam background monitor at LEP II. ((orig.))

  3. Experience with safety assessment of digital upgrading of IandC in VVER type reactors

    International Nuclear Information System (INIS)

    Wach, D.; Mulka, B.; Schnuerer, G.

    1997-01-01

    The digital upgrading of IandC systems important to safety in WWER type reactors requires a broad expertise in various knowledge fields. The approach of the Institute for safety Technology to the qualification and categorization of safety-critical software systems is highlighted. The role of the Institute in the qualification of the Teleperm XS and the type testing of its components is described. The aspects of the safety assessment of digital IandC systems in WWER type reactors is discussed in some detail. (A.K.)

  4. The upgrade of the forward Muon Spectrometer of the ATLAS Experiment: the New Small Wheel project

    CERN Document Server

    Iengo, Paolo; The ATLAS collaboration

    2017-01-01

    The current innermost stations of the ATLAS endcap muon tracking system (the Small Wheel) will be upgraded in 2019 and 2020 to retain the good precision tracking and trigger capabilities in the high background environment expected with the upcoming luminosity increase of the LHC. The upgraded detector will consist of eight layers each of Resistive Micromegas (MM) and small-strip Thin Gap Chambers (sTGC) together forming the ATLAS New Small Wheels. Large area sTGC's up to 2 m2 in size and totaling an active area each of 1200 m2 will be employed for fast and precise triggering. The required spatial resolution of about 100 μm will allow the Level-1 trigger track segments to be reconstructed with an angular resolution of approximately 1mrad. The precision cathode plane has strips with a 3.2mm pitch for precision readout and the cathode plane on the other side has pads to produce a 3-out-of-4 coincidence to identify passage of a track in an sTGC quadruplet, selecting which strips to read-out. The eight layers of ...

  5. Ion cyclotron radio frequency systems and performance on the tandem mirror experiment-upgrade (TMX-U)

    International Nuclear Information System (INIS)

    Moore, T.L.; Molvik, A.W.; Cummins, W.F.; Pedrotti, L.R.; Henderson, A.L.; Karsner, P.G.; Scofield, D.W.; Brooksby, C.A.

    1983-01-01

    High power ion cyclotron radio frequency (ICRF) systems are now gaining greater attention than before as prime driver ion heating systems. Lawrence Livermore National Laboratory (LLNL) has installed a 200 kW high frequency (HF) transmitter system on its Tandem Mirror Experiment-Upgrade (TMX-U). This paper describes the system, antenna, controls, and monitoring apparatus. The transmitter operates into a high Q antenna installed in the central cell region of the experiment. It incorporates a dual-port feedback system to automatically adjust the transmitter's output power and allow the maximum consistent with the plasma loading of the antenna. Special techniques have been used to measure, in real-time, the dynamically changing loading values presented by the plasma. From the measurements, the antenna impedance can be optimized for specified plasma density

  6. Upgrade of the LHC Schottky Monitor, Operational Experience and First Results

    CERN Document Server

    Betz, Michael; Lefèvre, Thibaut; Wendt, Manfred

    2016-01-01

    The LHC Schottky system allows the measurement of beam parameters such as tune and chromaticity in an entirely non-invasive way by extracting information from the statistical fluctuations in the incoherent motion of particles. The system was commissioned in 2011 and provided satisfactory beam-parameter measurements during LHC run 1 for lead-ions. However, for protons its usability was substantially limited due to strong interfering signals originating from the coherent motion of the particle bunch. The system has recently been upgraded with optimized travelling-wave pick-ups and an improved 4.8~GHz microwave signal path, with the front-end and the triple down-mixing chain optimized to reduce coherent signals. Design and operational aspects for the complete system are shown and the results from measurements with LHC beams in Run II are presented and discussed.

  7. VVER-440 training simulators upgrades - Experience of CORYS T.E.S.S

    International Nuclear Information System (INIS)

    Bartak, J.; Fallon, B.

    2006-01-01

    The paper presents recent projects of upgrading screen operated simulators of VVER-440 nuclear power plants to full scale replica simulators, implemented by CORYS TESS. Control room replica full scope simulators were built for the Bohunice NPP in Slovakia and the Novovoronezh NPP in Russia. The scope of simulation was extended to reflect the current status of the units, which have undergone significant modernization programs over the last few years. The paper describes the software and hardware adaptations and evolutions of the existing simulators, the implementation in the simulator of modern supervision systems as well as of systems and equipment designed in the seventies and still used on the reference units. The training benefits of parallel use of control room replica and screen-operated simulators in the training process are discussed. (author)

  8. Letter of Intent for the Phase-I Upgrade of the ATLAS Experiment

    CERN Document Server

    ATLAS Collaboration

    2011-01-01

    After the first successful years of running at the LHC, the ATLAS Collaboration is preparing to fully exploit the unprecedented physics opportunities offered by exploration of a completely new energy domain. This program builds on the excellent LHC accelerator complex performance demonstrated to date. A plan to consolidate and improve the physics capabilities of the current detector over the next decade, targeting the 2018 LHC shutdown as installation milestone, is presented in this Letter of Intent. The document primarily addresses the proposed enhancements to the ATLAS trigger system to cope with luminosities beyond the LHC nominal design value, while retaining the same physics performance. The Phase-I upgrades will allow ATLAS to maintain low pT trigger thresholds for isolated leptons by increasing the granularity of the calorimeters involved in the Level-1 trigger and by introducing new muon trigger and tracking detectors in the forward direction. Precision measurements of the couplings of the Higgs boson...

  9. Full kinematic reconstruction of charged B mesons with the upgraded Inner Tracking System of the ALICE Experiment

    CERN Document Server

    AUTHOR|(CDS)2074762

    In this thesis, the performance of the full kinematic reconstruction of $\\mathrm{{B}}^{+}$ mesons in the decay channel $\\mathrm{{B}}^{+}\\rightarrow\\mathrm{\\overline{D}^{0}}\\pi^{+}$ ($\\mbox{$\\mathrm{\\overline{D}^{0}}\\rightarrow \\mathrm{K}^{+}\\pi^{-}$}$) and charge conjugates for the 0-10 % most central Pb-Pb collisions at $\\sqrt{s_{_{\\mathrm{NN}}}}$ = 5.5 TeV is demonstrated for the upgraded ALICE Experiment, which is planned before Run 3 of the Large Hadron Collider (LHC), beginning in 2020. Within the scope of the foreseen detector and readout upgrades to inspect all Pb-Pb collisions at their interaction rate of 50 kHz, in particular through the installation of a new high-granularity pixel inner tracker, for the first time these rare signals will become accessible using full kinematic reconstruction in central Pb-Pb collisions in ALICE at mid-rapidity at the LHC. Topological and kinematic criteria are used to select the beauty signal against the large combinatorial and correlated background. In addition to a...

  10. The Phase-1 Upgrade for the Level-1 Muon Barrel Trigger of the ATLAS Experiment at LHC

    CERN Document Server

    Izzo, Vincenzo; The ATLAS collaboration

    2018-01-01

    The Level-1 Barrel Trigger of the ATLAS Experiment is based on Resistive Plate Chambers (RPC) detectors. The on-detector trigger electronics identifies muons with specific values of transverse momentum (pT), by using coincidences between different layers of detectors. Trigger data is then transferred from on-detector to the off-detector trigger electronics boards. Data is processed by a complex system, which combines trigger data from the Barrel and the End-cap regions, and provides the combined muon candidate to the Central Trigger Processor (CTP). The system has been performing very well for almost a decade. However, in order to cope with continuously increasing LHC luminosity and more demanding requirements on trigger efficiency and performance, various upgrades for the full trigger system were already deployed, and others are foreseen in the next years. Most of the trigger upgrades are based on state-of-the-art technologies and allow designing more complex trigger menus, increasing processing power and da...

  11. The Phase-1 Upgrade for the Level-1 Muon Barrel Trigger of the ATLAS Experiment at LHC

    CERN Document Server

    Izzo, Vincenzo; The ATLAS collaboration

    2018-01-01

    The Level-1 Muon Barrel Trigger of the ATLAS Experiment at LHC makes use of Resistive Plate Chamber (RPC) detectors. The on-detector trigger electronics modules are able to identify muons with predefined transverse momentum values (pT) by executing a coincidence logic on signals coming from the various detector layers. Then, on-detector trigger boards transfer trigger data to the off-detector electronics. A complex trigger system processes the incoming data by combining trigger information from the Barrel and the End-cap regions, and by providing the combined muon candidate to the Central Trigger Processor (CTP). For almost a decade, the Level-1 Trigger system has been operating very well, despite the challenging requirements on trigger efficiency and performance, and the continuously increasing LHC luminosity. In order to cope with these constraints, various upgrades for the full trigger system were already deployed, and others have been designed to be installed in the next years. Most of the upgrades to the...

  12. An Asdex-type divertor for ITER

    International Nuclear Information System (INIS)

    Fowler, T.K.

    1989-01-01

    An Asdex-type local divertor is proposed for ITER consisting of a copper poloidal field coil adjacent to the plasma. Estimates indicate that the power consumption is acceptable. Advantages would be a much reduced heat load not very sensitive to magnetic perturbations. A disadvantage is the finite lifetime under neutron bombardment that would require periodic replacement of the divertor coils in a reactor, but probably not in ITER because of its limited fluence. Another disadvantage would be poorer blanket coverage unless the divertor coil itself incorporates breeding material. 3 figs

  13. Heat and density pulse propagation in ASDEX

    International Nuclear Information System (INIS)

    Giannone, L.; Riedl, K.; Stroth, U.; Eberhagen, A.; Gruber, O.; Mertens, V.

    1990-01-01

    Experimental measurements of the electron thermal conductivity, derived from the radial propagation of the heat pulse generated by a sawtooth crash, have consistently yielded larger values than those obtained by power balance. It has been proposed that this discrepancy could be the result of the coupling of density and temperature perturbations. Numerical modelling of heat and density pulse propagation on ASDEX has been used to address this question. In addition, measurements at various electron densities and in hydrogen and deuterium were undertaken, with the aim of providing a broad base of experimental measurements for testing the various transport models proposed. (author) 9 refs., 1 fig

  14. Heat and density pulse propagation in ASDEX

    International Nuclear Information System (INIS)

    Giannone, L.; Riedel, K.; Stroth, U.; Eberhagen, A.; Gruber, O.; Mertens, V.

    1990-01-01

    Experimental measurements of the electron thermal conductivity, derived from the radial propagation of the heat pulse generated by a sawtooth crash, have consistently yielded larger values than those obtained by power balance. It has been proposed that this discrepancy could be the result of the coupling of density and temperature perturbations. Numerical modelling of heat and density pulse propagation on ASDEX has been used to address this question. In addition, measurements at various electron densities and in hydrogen and deuterium were undertaken, with the aim of providing a broad base of experimental measurements for testing the various transport models proposed. (orig.)

  15. Linear stability of microtearing modes in ASDEX

    International Nuclear Information System (INIS)

    Giannone, L.

    1987-12-01

    The linear stability of microtearing modes in typical ASDEX discharges have been calculated. In the case of Ohmic discharges it was found that unstable modes are predicted to be located towards the centre of the plasma. For L and H discharges the zone of instability shifts towards the plasma edge. The interpretation of an increase or decrease in the amplitude of broadband magnetic fluctuations during L and H discharges must be interpreted with caution, since the amplitude observed is strongly dependent on the radial position of the instability. (orig./GG)

  16. The ATLAS Data Acquisition and High Level Trigger Systems: Experience and Upgrade Plans

    CERN Document Server

    Hauser, R; The ATLAS collaboration

    2012-01-01

    The ATLAS DAQ/HLT system reduces the Level 1 rate of 75 kHz to a few kHz event build rate after Level 2 and a few hundred Hz out output rate to disk. It has operated with an average data taking efficiency of about 94% during the recent years. The performance has far exceeded the initial requirements, with about 5 kHz event building rate and 500 Hz of output rate in 2012, driven mostly by physics requirements. Several improvements and upgrades are foreseen in the upcoming long shutdowns, both to simplify the existing architecture and improve the performance. On the network side new core switches will be deployed and possible use of 10GBit Ethernet links for critical areas is foreseen. An improved read-out system to replace the existing solution based on PCI is under development. A major evolution of the high level trigger system foresees a merging of the Level 2 and Event Filter functionality on a single node, including the event building. This will represent a big simplification of the existing system, while ...

  17. Small-Strip Thin Gap Chambers for the Muon Spectrometer Upgrade of the ATLAS Experiment

    CERN Document Server

    Perez Codina, Estel; The ATLAS collaboration

    2015-01-01

    For the forthcoming Phase-I upgrade to the LHC (2018/19), the first station of the ATLAS muon end-cap system, Small Wheel, needs to be replaced. The New Small Wheel (NSW) will have to operate in a high background radiation region while reconstructing muon tracks with high precision and providing information for the Level-1 trigger. In particular, the precision reconstruction of tracks requires a spatial resolution of about 100 μm, and the Level-1 trigger track segments have to be reconstructed with an angular resolution of approximately 1 mrad. The NSWs consist of eight layers each of Micromegas and small-strip Thin Gap Chambers (sTGC), both providing trigger and tracking capabilities. The single sTGC planes of a quadruplet consists of an anode layer of 50μm gold plated tungsten wire sandwiched between two resistive cathode layers. Behind one of the resistive cathode layers, a PCB with precise machined strips (thus the name sTGC) spaced every 3.2mm allows to achieve a position resolution that ranges from 70...

  18. Upgrade of the InGrid based X-ray detector for the CAST experiment

    Energy Technology Data Exchange (ETDEWEB)

    Desch, Klaus; Kaminski, Jochen; Krieger, Christoph; Schmidt, Sebastian [Physikalisches Institut, Universitaet Bonn, Nussallee 12, 53115 Bonn (Germany)

    2016-07-01

    The CERN Axion Solar Telescope (CAST) is a magnetic helioscope searching for solar axions and chameleons using the inverse Primakoff effect. The produced photons are in the low X-ray regime. Chameleon search demands high sensitivity to photons with less than 1 keV and a very low background rate. Several improvements to the detector design used in 2014/15 are envisaged for 2016. The readout system is to be improved by including a flash ADC to read out the analog signal induced on the grid. The pulse shape contains information about the longitudinal shape of the event in addition to the transverse shape given by the pixel read out. Tracks passing through the chip orthogonally resemble photons in transverse shape. A scintillator behind the detector will also allow cross referencing chip and and scintillator signals to further reduce background rates. Finally, a new X-ray window separating detector and X-ray telescope volume from one another will be installed. Due to the low expected signal rate, a window with very low X-ray opacity is needed. Due to a pressure difference of ∝1 bar between detector and the vacuum of CAST this is demanding. The usage of silicon nitride windows is being explored. The current progress of the detector upgrade will be presented.

  19. Boosted object hardware trigger development and testing for the Phase I upgrade of the ATLAS Experiment

    CERN Document Server

    Stark, Giordon Holtsberg; The ATLAS collaboration

    2015-01-01

    The Global Feature Extraction (gFEX) module is a Level 1 jet trigger system planned for installation in ATLAS during the Phase 1 upgrade in 2018. The gFEX selects large-radius jets for capturing Lorentz-boosted objects by means of wide-area jet algorithms refined by subjet information. The architecture of the gFEX permits event-by-event local pile-up suppression for these jets using the same subtraction techniques developed for offline analyses. The gFEX architecture is also suitable for other global event algorithms such as missing transverse energy (MET), centrality for heavy ion collisions, and "jets without jets". The gFEX will use 4 processor FPGAs to perform calculations on the incoming data and a Hybrid APU-FPGA for slow control of the module. The gFEX is unique in both design and implementation and substantially enhance the selectivity of the L1 trigger and increases sensitivity to key physics channels.

  20. The Layout and Performance of the Phase-II upgrade of the tracking detector of the ATLAS experiment

    CERN Document Server

    Ai, Xiaocong; The ATLAS collaboration

    2017-01-01

    HL-LHC will deliver about 3000 fb-1 of integrated luminosity in over 10 year. This will present an extremely challenging environment to the ATLAS experiment, well beyond that for which it was designed. In ATLAS Phase II upgrade, the Inner Detector will be replace by a new all-silicon Inner Tracker to maintain tracking performance in this high-occupancy environment and to cope with the increase of approximately a factor of ten in the integrated radiation dose. The ITk Detector layout is designed to meet the requirement for identifying charged particles with high efficiency and measuring their properties with high precision in the denser environment. The Layout and performance of the ITk is presented.

  1. Full kinematic reconstruction of charged B mesons with the upgraded inner tracking system of the ALICE experiment

    Energy Technology Data Exchange (ETDEWEB)

    Stiller, Johannes Hendrik

    2016-05-11

    In this thesis, the performance of the full kinematic reconstruction of B{sup +} mesons in the decay channel B{sup +}→ anti D{sup 0}π{sup +}(anti D{sup 0}→K{sup +}π{sup -}) and charge conjugates for the 0-10% most central Pb-Pb collisions at √(s{sub NN})=5.5 TeV is demonstrated for the upgraded ALICE Experiment, which is planned before Run 3 of the Large Hadron Collider (LHC), beginning in 2020. Within the scope of the foreseen detector and readout upgrades to inspect all Pb-Pb collisions at their interaction rate of 50 kHz, in particular through the installation of a new high-granularity pixel inner tracker, for the first time these rare signals will become accessible using full kinematic reconstruction in central Pb-Pb collisions in ALICE at mid-rapidity at the LHC. Topological and kinematic criteria are used to select the beauty signal against the large combinatorial and correlated background. In addition to available full Monte Carlo (MC) simulations, a fast MC simulation, which includes parameterizations of all relevant detector effects, was developed and is now generally available for all rare probe studies with the upgraded ALICE detector. The fast simulation was used to improve the estimate on the residual combinatorial background in order to maximize the expected signal-to-background ratio and statistical significance. Within the uncertainties of the expected signal yield, a significant measurement (≥5) will be possible down to p{sub T} ≥ 2.0 GeV/c, corresponding to about 88% of the yield. The signal-to-background ratio lies between 0.01 and 4.0, increasing with p{sub T}. The required reference statistics in p+p collisions at √(s)=5.5 TeV was estimated to be about 100 pb{sup -1}. Considering the calculated expected statistics, the precision of the measurements of the nuclear modification factor R{sub AA} and the elliptic flow v{sub 2} were estimated. A measurement of the theoretically predicted R{sub AA} of 0.2-0.5 above p{sub T}≥5.0 Ge

  2. Upgrade of the BATMAN test facility for H- source development

    Science.gov (United States)

    Heinemann, B.; Fröschle, M.; Falter, H.-D.; Fantz, U.; Franzen, P.; Kraus, W.; Nocentini, R.; Riedl, R.; Ruf, B.

    2015-04-01

    The development of a radio frequency (RF) driven source for negative hydrogen ions for the neutral beam heating devices of fusion experiments has been successfully carried out at IPP since 1996 on the test facility BATMAN. The required ITER parameters have been achieved with the prototype source consisting of a cylindrical driver on the back side of a racetrack like expansion chamber. The extraction system, called "Large Area Grid" (LAG) was derived from a positive ion accelerator from ASDEX Upgrade (AUG) using its aperture size (ø 8 mm) and pattern but replacing the first two electrodes and masking down the extraction area to 70 cm2. BATMAN is a well diagnosed and highly flexible test facility which will be kept operational in parallel to the half size ITER source test facility ELISE for further developments to improve the RF efficiency and the beam properties. It is therefore planned to upgrade BATMAN with a new ITER-like grid system (ILG) representing almost one ITER beamlet group, namely 5 × 14 apertures (ø 14 mm). Additionally to the standard three grid extraction system a repeller electrode upstream of the grounded grid can optionally be installed which is positively charged against it by 2 kV. This is designated to affect the onset of the space charge compensation downstream of the grounded grid and to reduce the backstreaming of positive ions from the drift space backwards into the ion source. For magnetic filter field studies a plasma grid current up to 3 kA will be available as well as permanent magnets embedded into a diagnostic flange or in an external magnet frame. Furthermore different source vessels and source configurations are under discussion for BATMAN, e.g. using the AUG type racetrack RF source as driver instead of the circular one or modifying the expansion chamber for a more flexible position of the external magnet frame.

  3. Upgrade of the BATMAN test facility for H− source development

    International Nuclear Information System (INIS)

    Heinemann, B.; Fröschle, M.; Falter, H.-D.; Fantz, U.; Franzen, P.; Kraus, W.; Nocentini, R.; Riedl, R.; Ruf, B.

    2015-01-01

    The development of a radio frequency (RF) driven source for negative hydrogen ions for the neutral beam heating devices of fusion experiments has been successfully carried out at IPP since 1996 on the test facility BATMAN. The required ITER parameters have been achieved with the prototype source consisting of a cylindrical driver on the back side of a racetrack like expansion chamber. The extraction system, called “Large Area Grid” (LAG) was derived from a positive ion accelerator from ASDEX Upgrade (AUG) using its aperture size (ø 8 mm) and pattern but replacing the first two electrodes and masking down the extraction area to 70 cm2. BATMAN is a well diagnosed and highly flexible test facility which will be kept operational in parallel to the half size ITER source test facility ELISE for further developments to improve the RF efficiency and the beam properties. It is therefore planned to upgrade BATMAN with a new ITER-like grid system (ILG) representing almost one ITER beamlet group, namely 5 × 14 apertures (ø 14 mm). Additionally to the standard three grid extraction system a repeller electrode upstream of the grounded grid can optionally be installed which is positively charged against it by 2 kV. This is designated to affect the onset of the space charge compensation downstream of the grounded grid and to reduce the backstreaming of positive ions from the drift space backwards into the ion source. For magnetic filter field studies a plasma grid current up to 3 kA will be available as well as permanent magnets embedded into a diagnostic flange or in an external magnet frame. Furthermore different source vessels and source configurations are under discussion for BATMAN, e.g. using the AUG type racetrack RF source as driver instead of the circular one or modifying the expansion chamber for a more flexible position of the external magnet frame

  4. Tandem Mirror Experiment-Upgrade neutral beam test stand: A powerful tool for development and quality assurance

    International Nuclear Information System (INIS)

    Hibbs, S.M.; Kane, R.J.; Kerr, R.G.; Poulsen, P.

    1983-01-01

    During construction of the Tandem Mirror Experiment-Upgrade (TMX-U), a test stand was assembled to develop electronics for the neutral beam system. In the first six months of test stand use the authors operated a few neutral beam injector modules and directed considerable effort toward improving the electronic system. As system development progressed, the focus turned toward improving the injector modules themselves. The test stand has proved to be the largest single contributor to the successful operation of neutral beams on TMX-U, primarily because it provides quality assurance and development capability in conjunction with the scheduled activities of the main experiment. This support falls into five major categories: (1) electronics development, (2) operator training, (3) injector module testing and characterization, (4) injector module improvements, and (5) physics improvements (through areas affected by injector operation). Normal day-to-day operation of the test stand comes under the third category, testing and characterization, and comprises the final quality assurance activity for newly assembled or repaired modules before they are installed on TMX-U. They have also used the test stand to perform a series of physics experiments, including: reducing gas flow through valve and arc chamber characterization, reducing impurities by titanium gettering, and reducing streaming gas using apertures and collisional gas dynamics

  5. Upgrading of TREAT experimental capabilities

    International Nuclear Information System (INIS)

    Dickerman, C.E.; Rose, D.; Bhattacharyya, S.K.

    1982-01-01

    The TREAT facility at the Argonne National Laboratory site in the Idaho National Engineering Laboratory is being upgraded to provide capabilities for fast-reactor-safety transient experiments not possible at any other experimental facility. Principal TREAT Upgrade (TU) goal is provision for 37-pin size experiments on energetics of core-disruptive accidents (CDA) in fast breeder reactor cores with moderate sodium void coefficients. this goal requires a significant enhancement of the capabilities of the TREAT facility, specifically including reactor control, hardened neutron spectrum incident on the test sample, and enlarged building. The upgraded facility will retain the capability for small-size experiments of the types currently being performed in TREAT. Reactor building and crane upgrading have been completed. TU schedules call for the components of the upgraded reactor system to be finished in 1984, including upgraded TREAT fuel and control system, and expanded coverage by the hodoscope fuel-motion diagnostics system

  6. The LHCb Muon Upgrade

    CERN Multimedia

    Cardini, A

    2013-01-01

    The LHCb collaboration is currently working on the upgrade of the experiment to allow, after 2018, an efficient data collection while running at an instantaneous luminosity of 2x10$^{33}$/cm$^{-2}$s$^{-1}$. The upgrade will allow 40 MHz detector readout, and events will be selected by means of a very flexible software-based trigger. The muon system will be upgraded in two phases. In the first phase, the off-detector readout electronics will be redesigned to allow complete event readout at 40 MHz. Also, part of the channel logical-ORs, used to reduce the total readout channel count, will be removed to reduce dead-time in critical regions. In a second phase, higher-granularity detectors will replace the ones installed in highly irradiated regions, to guarantee efficient muon system performances in the upgrade data taking conditions.

  7. Radiation safety experience in upgrading 2-5% heavy water wastes at Heavy Water Plant, Nangal (Preprint No. SA-7)

    International Nuclear Information System (INIS)

    Sadhukhan, H.K.; Behl, D.; Ramraj; Iyengar, T.S.; Sadarangani, S.H.; Vaze, P.K.; Soman, S.D.

    1989-04-01

    This paper describes the radiological safety experience in upgrading 2-5% heavy water wastes at Heavy Water Plant at Nangal at the third stage electrolysers. The feed water concentrations at the third stage electrolyer was determined after a safety analysis study and pilot plant experiment, which gave the optimal concentrations of 1 to 1.5 mCi (3.7 to 5.5 x 10 7 Bq) per litre per minute feed from a submerged SS tank containing 2-5% heavy water wastes. This process not only yielded an efficient recovery of reactor grade heavy water but contained the tritium activity in the third stage electrolysers and in the final product viz., heavy water. The tritium concentrations were continuously monitore d by liquid scintillation counting method at all the three stages of electrolysis plant, the distillation plant, the heavy water filling rooms, the drains, the ambient air, the product fertilizer (calcium ammonia nitrate) and the Sutlej River and found to be well within the safety limits set for general public at large. The HD and D 2 process streams in the palnt were monitored using fill-in type of ionization chambers designed for the purpose, which served a D 2 inventory check as well. There was no internal exposure to any personnel during the entire period of programme. (author). 2 tabs

  8. Tandem mirror experiment-upgrade neutral beam test stand: a powerful tool for development and quality assurance

    International Nuclear Information System (INIS)

    Hibbs, S.M.; Kane, R.J.; Kerr, R.G.; Poulsen, P.

    1983-01-01

    During construction of the Tandem Mirror Experiment-Upgrade (TMX-U), we assembled a test stand to develop electronics for the neutral beam system. In the first six months of test stand use we operated a few neutral beam injector modules and directed considerable effort toward improving the electronic system. As system development progressed, our focus turned toward improving the injector modules themselves. The test stand has proved to be the largest single contributor to the successful operation of neutral beams on TMX-U, primarily because it provides quality assurance andd development capability in conjunction with the scheduled activities of the main experiment. This support falls into five major categories: (1) electronics development, (2) operator training, (3) injector module testing and characterization, (4) injector module improvements, and (5) physics improvements (through areas affected by injector operation). Normal day-to-day operation of the test stand comes under the third category, testing and characterization, and comprises our final quality assurance activity for newly assembled or repaired modules before they are installed on TMX-U

  9. Phase II Upgrade of the GERDA Experiment for the Search of Neutrinoless Double Beta Decay

    Science.gov (United States)

    Majorovits, B.

    Observation of neutrinoless double beta decay could answer the question regarding the Majorana or Dirac nature of neutrinos. The GERDA experiment utilizes HPGe detectors enriched with the isotope 76Ge to search for this process. Recently the GERDA collaboration has unblinded data of Phase I of the experiment. In order to further improve the sensitivity of the experiment, additionally to the coaxial detectors used, 30 BEGe detectors made from germanium enriched in 76Ge will be deployed