WorldWideScience

Sample records for asdex upgrade invited

  1. 2D electron cyclotron emission imaging at ASDEX Upgrade (invited)

    Energy Technology Data Exchange (ETDEWEB)

    Classen, I. G. J. [Max Planck Institut fuer Plasmaphysik, 85748 Garching (Germany); FOM-Institute for Plasma Physics, Rijnhuizen, 3430 BE Nieuwegein (Netherlands); Boom, J. E.; Vries, P. C. de [FOM-Institute for Plasma Physics, Rijnhuizen, 3430 BE Nieuwegein (Netherlands); Suttrop, W.; Schmid, E.; Garcia-Munoz, M.; Schneider, P. A. [Max Planck Institut fuer Plasmaphysik, 85748 Garching (Germany); Tobias, B.; Domier, C. W.; Luhmann, N. C. Jr. [University of California at Davis, Davis, California 95616 (United States); Donne, A. J. H. [FOM-Institute for Plasma Physics, Rijnhuizen, 3430 BE Nieuwegein (Netherlands); Eindhoven University of Technology, 5600 MB Eindhoven (Netherlands); Jaspers, R. J. E. [Eindhoven University of Technology, 5600 MB Eindhoven (Netherlands); Park, H. K. [POSTECH, Pohang, Gyeongbuk, 790-784 (Korea, Republic of); Munsat, T. [University of Colorado, Boulder, Colorado 80309 (United States)

    2010-10-15

    The newly installed electron cyclotron emission imaging diagnostic on ASDEX Upgrade provides measurements of the 2D electron temperature dynamics with high spatial and temporal resolution. An overview of the technical and experimental properties of the system is presented. These properties are illustrated by the measurements of the edge localized mode and the reversed shear Alfven eigenmode, showing both the advantage of having a two-dimensional (2D) measurement, as well as some of the limitations of electron cyclotron emission measurements. Furthermore, the application of singular value decomposition as a powerful tool for analyzing and filtering 2D data is presented.

  2. 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; Furtula, Vedran; Leuterer, F.; Leipold, Frank; Michelsen, Poul; Nielsen, Stefan Kragh; Salewski, Mirko; Stober, J.; Wagner, D.; Woskov, P.

    2008-01-01

    The collective Thomson scattering (CTS) diagnostic installed on ASDEX Upgrade uses millimeter waves generated by the newly installed 1 MW dual frequency gyrotron as probing radiation at 105 GHz. It measures backscattered radiation with a heterodyne receiver having 50 channels (between 100 and 110...... alignment 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...

  3. 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...

  4. 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...

  5. Nitrogen retention in ASDEX Upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Meisl, G., E-mail: gmeisl@ipp.mpg.de [Max-Planck-Institut für Plasmaphysik, Boltzmannstraße 2, 85748 Garching (Germany); Physik-Department E28, Technische Universität München, 85747 Garching (Germany); Schmid, K.; Oberkofler, M.; Krieger, K. [Max-Planck-Institut für Plasmaphysik, Boltzmannstraße 2, 85748 Garching (Germany); Lisgo, S.W. [ITER Organization, FST, Route de Vinon, CS 90 046, 13067 Saint Paul Lez Durance Cedex (France); Aho-Mantila, L. [VTT, FI-02044 VTT (Finland); Reimold, F. [Max-Planck-Institut für Plasmaphysik, Boltzmannstraße 2, 85748 Garching (Germany)

    2015-08-15

    We investigated the transport of nitrogen through the plasma and the interaction of nitrogen with tungsten under divertor exposure conditions during nitrogen-seeding experiments in ASDEX Upgrade. Using the divertor manipulator system, tungsten samples were exposed to well-characterized L-mode plasmas with and without nitrogen seeding. We also simulated nitrogen transport and re-distribution in these discharges by self-consistent WallDYN–DIVIMP modeling. For these simulations we applied a W–N surface model based on laboratory experiments and plasma backgrounds from SOLPS. In contrast to the conclusion from Kallenbach and Dux (2010) [5] we find that the N retention in ASDEX Upgrade is in agreement with results from laboratory experiments.

  6. Overview of ASDEX Upgrade results

    Science.gov (United States)

    Zohm, H.; Angioni, C.; Arslanbekov, R.; Atanasiu, C.; Becker, G.; Becker, W.; Behler, K.; Behringer, K.; Bergmann, A.; Bilato, R.; Bobkov, V.; Bolshukhin, D.; Bolzonella, T.; Borrass, K.; Brambilla, M.; Braun, F.; Buhler, A.; Carlson, A.; Conway, G. D.; Coster, D. P.; Drube, R.; Dux, R.; Egorov, S.; Eich, T.; Engelhardt, K.; Fahrbach, H.-U.; Fantz, U.; Faugel, H.; Finken, K. H.; Foley, M.; Franzen, P.; Fuchs, J. C.; Gafert, J.; Fournier, K. B.; Gantenbein, G.; Gehre, O.; Geier, A.; Gernhardt, J.; Goodman, T.; Gruber, O.; Gude, A.; Günter, S.; Haas, G.; Hartmann, D.; Heger, B.; Heinemann, B.; Herrmann, A.; Hobirk, J.; Hofmeister, F.; Hohenöcker, H.; Horton, L. D.; Igochine, V.; Jacchia, A.; Jakobi, M.; Jenko, F.; Kallenbach, A.; Kardaun, O.; Kaufmann, M.; Keller, A.; Kendl, A.; Kim, J.-W.; Kirov, K.; Kochergov, R.; Kollotzek, H.; Kraus, W.; Krieger, K.; Kurki-Suonio, T.; Kurzan, B.; Lang, P. T.; Lasnier, C.; Lauber, P.; Laux, M.; Leonard, A. W.; Leuterer, F.; Lohs, A.; Lorenz, A.; Lorenzini, R.; Maggi, C.; Maier, H.; Mank, K.; Manso, M.-E.; Mantica, P.; Maraschek, M.; Martines, E.; Mast, K.-F.; McCarthy, P.; Meisel, D.; Meister, H.; Meo, F.; Merkel, P.; Merkel, R.; Merkl, D.; Mertens, V.; Monaco, F.; Mück, A.; Müller, H. W.; Münich, M.; Murmann, H.; Na, Y.-S.; Neu, G.; Neu, R.; Neuhauser, J.; Nguyen, F.; Nishijima, D.; Nishimura, Y.; Noterdaeme, J.-M.; Nunes, I.; Pautasso, G.; Peeters, A. G.; Pereverzev, G.; Pinches, S. D.; Poli, E.; Proschek, M.; Pugno, R.; Quigley, E.; Raupp, G.; Reich, M.; Ribeiro, T.; Riedl, R.; Rohde, V.; Roth, J.; Ryter, F.; Saarelma, S.; Sandmann, W.; Savtchkov, A.; Sauter, O.; Schade, S.; Schilling, H.-B.; Schneider, W.; Schramm, G.; Schwarz, E.; Schweinzer, J.; Schweizer, S.; Scott, B. D.; Seidel, U.; Serra, F.; Sesnic, S.; Sihler, C.; Silva, A.; Sips, A. C. C.; Speth, E.; Stäbler, A.; Steuer, K.-H.; Stober, J.; Streibl, B.; Strumberger, E.; Suttrop, W.; Tabasso, A.; Tanga, A.; Tardini, G.; Tichmann, C.; Treutterer, W.; Troppmann, M.; Urano, H.; Varela, P.; Vollmer, O.; Wagner, D.; Wenzel, U.; Wesner, F.; Westerhof, E.; Wolf, R.; Wolfrum, E.; Würsching, E.; Yoon, S.-W.; Yu, Q.; Zasche, D.; Zehetbauer, T.; Zehrfeld, H.-P.

    2003-12-01

    Recent results from the ASDEX Upgrade experimental campaigns 2001 and 2002 are presented. An improved understanding of energy and particle transport emerges in terms of a 'critical gradient' model for the temperature gradients. Coupling this to particle diffusion explains most of the observed behaviour of the density profiles, in particular, the finding that strong central heating reduces the tendency for density profile peaking. Internal transport barriers (ITBs) with electron and ion temperatures in excess of 20 keV (but not simultaneously) have been achieved. By shaping the plasma, a regime with small type II edge localized modes (ELMs) has been established. Here, the maximum power deposited on the target plates was greatly reduced at constant average power. Also, an increase of the ELM frequency by injection of shallow pellets was demonstrated. ELM free operation is possible in the quiescent H-mode regime previously found in DIII-D which has also been established on ASDEX Upgrade. Regarding stability, a regime with benign neoclassical tearing modes (NTMs) was found. During electron cyclotron current drive (ECCD) stabilization of NTMs, bgrN could be increased well above the usual onset level without a reappearance of the NTM. Electron cyclotron resonance heating and ECCD have also been used to control the sawtooth repetition frequency at a moderate fraction of the total heating power. The inner wall of the ASDEX Upgrade vessel has increasingly been covered with tungsten without causing detrimental effects on the plasma performance. Regarding scenario integration, a scenario with a large fraction of noninductively driven current (geq50%), but without ITB has been established. It combines improved confinement (tgrE/tgrITER98 ap 1.2) and stability (bgrN les 3.5) at high Greenwald fraction (ne/nGW ap 0.85) in steady state and with type II ELMy edge and would offer the possibility for long pulses with high fusion power at reduced current in ITER.

  7. 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...... threshold in He are more favourable than in H, suggesting that He operation could allow us to assess H-mode operation in the non-nuclear phase of ITER operation....

  8. Overview of ASDEX Upgrade results

    International Nuclear Information System (INIS)

    Significant progress has been made on ASDEX Upgrade during the last two years in the basic understanding of transport, in the extension of the improved H-mode in parameter space and towards an integrated operating scenario, and in the development of control methods for major performance limiting instabilities. Highlights were the understanding of particle transport and the control of impurity accumulation based on it, the satisfactory operation with predominantly tungsten-clad walls, the improved H-mode operation over density ranges and for temperature ratios covering the ITER requirements on ν*, n/nGW and Te/Ti, the ELM frequency control by pellet injection, and the optimisation of NTM suppression by DC-ECCD through variation of the launching angle. From these experiments an integrated scenario has emerged which extrapolates to a 50 % improvement in nTτ or a 30 % reduction of the required current compared to the ITER base-line assumptions, with moderately peaked electron and controllable high-Z density profiles. (author)

  9. Disruption studies on ASDEX upgrade

    International Nuclear Information System (INIS)

    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

  10. Disruption studies in ASDEX Upgrade

    International Nuclear Information System (INIS)

    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)

  11. 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

  12. Recent ECRH results in ASDEX Upgrade

    International Nuclear Information System (INIS)

    We report about experiments in ASDEX Upgrade using our ECRH system with f = 140 GHz, P = 4 x 0.5 MW, and T = 2 sec. The following topics are covered: studies of modulated power deposition, studies of the electron heat transport via power balance analysis and heat wave analysis and a comparison with turbulent transport theory, generation of an internal transport barrier for the electron heat flux, impact of ECRH on particle and impurity transport, and studies related to neoclassical tearing modes and to sawteeth. (authors)

  13. Nitrogen migration and retention in ASDEX upgrade

    International Nuclear Information System (INIS)

    To limit the power load in high-power plasma operation, impurity seeding is mandatory. Nitrogen has been established as optimal choice in ASDEX upgrade. However, as N is subject to wall pumping, a self-consistent model of the N source flux distribution is required. N retention in tungsten was studied in laboratory experiments under well-defined exposure conditions. The applicability of the so established model of W-N interaction was tested by experiments in ASDEX upgrade. W samples were exposed to plasmas with and without N seeding and analyzed by ion beam analysis. Using these data as boundary condition, N transport and re-distribution in the plasma were studied by self-consistent WallDYN-DIVIMP modelling. The dynamic change of the N erosion source at plasma exposed W surfaces was then computed by WallDYN using an improved W-N surface model. First simulations show, in agreement with the experiment, a strong rise of the N re-erosion flux within the first second. By this approach the experimental results from sample analysis, spectroscopy and N pumped by the vacuum system can be interpreted for the first time within a unified self-consistent model.

  14. Divertor geometry optimization for ASDEX Upgrade

    International Nuclear Information System (INIS)

    One of the critical questions to be solved for ITER (or any other reactor) is the power exhaust problem (compatible with particle exhaust). Optimized divertors have to be tested in existing geometries based mainly on the idea of closing them very efficiently to the main chamber and, by the choice of the plate and baffle geometry, positively influencing the flow pattern of hydrogen favoring good impurity entrainment. Also, for ASDEX Upgrade there is an experimental necessity for an improved divertor due to the increased heating power (24 MW will be available from 1997 on compared to the present 18 MW). We present the optimization strategy for the divertor II of ASDEX Upgrade, using elaborate numerical models and codes (B2-Eirene) as well as simple models. We start with the choice of a proper target plate geometry, and then further discuss how main chamber and private flux baffling will be done, and how this affects neutral recirculation pattern and pumping properties. For the final configuration the impurity entrainment properties are analyzed. (orig.)

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

    International Nuclear Information System (INIS)

    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)

  16. Pellet injection into ASDEX upgrade plasmas

    International Nuclear Information System (INIS)

    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.)

  17. The tungsten divertor experiment at ASDEX Upgrade

    Science.gov (United States)

    Neu, R.; Asmussen, K.; Krieger, K.; Thoma, A.; Bosch, H.-S.; Deschka, S.; Dux, R.; Engelhardt, W.; García-Rosales, C.; Gruber, O.; Herrmann, A.; Kallenbach, A.; Kaufmann, M.; Mertens, V.; Ryter, F.; Rohde, V.; Roth, J.; Sokoll, M.; Stäbler, A.; Suttrop, W.; Weinlich, M.; Zohm, H.; Alexander, M.; Becker, G.; Behler, K.; Behringer, K.; Behrisch, R.; Bergmann, A.; Bessenrodt-Weberpals, M.; Brambilla, M.; Brinkschulte, H.; Büchl, K.; Carlson, A.; Chodura, R.; Coster, D.; Cupido, L.; de Blank, H. J.; de Peña Hempel, S.; Drube, R.; Fahrbach, H.-U.; Feist, J.-H.; Feneberg, W.; Fiedler, S.; Franzen, P.; Fuchs, J. C.; Fußmann, G.; Gafert, J.; Gehre, O.; Gernhardt, J.; Haas, G.; Herppich, G.; Herrmann, W.; Hirsch, S.; Hoek, M.; Hoenen, F.; Hofmeister, F.; Hohenöcker, H.; Jacobi, D.; Junker, W.; Kardaun, O.; Kass, T.; Kollotzek, H.; Köppendörfer, W.; Kurzan, B.; Lackner, K.; Lang, P. T.; Lang, R. S.; Laux, M.; Lengyel, L. L.; Leuterer, F.; Manso, M. E.; Maraschek, M.; Mast, K.-F.; McCarthy, P.; Meisel, D.; Merkel, R.; Müller, H. W.; Münich, M.; Murmann, H.; Napiontek, B.; Neu, G.; Neuhauser, J.; Niethammer, M.; Noterdaeme, J.-M.; Pasch, E.; Pautasso, G.; Peeters, A. G.; Pereverzev, G.; Pitcher, C. S.; Poschenrieder, W.; Raupp, G.; Reinmüller, K.; Riedl, R.; Röhr, H.; Salzmann, H.; Sandmann, W.; Schilling, H.-B.; Schlögl, D.; Schneider, H.; Schneider, R.; Schneider, W.; Schramm, G.; Schweinzer, J.; Scott, B. D.; Seidel, U.; Serra, F.; Speth, E.; Silva, A.; Steuer, K.-H.; Stober, J.; Streibl, B.; Treutterer, W.; Troppmann, M.; Tsois, N.; Ulrich, M.; Varela, P.; Verbeek, H.; Verplancke, Ph; Vollmer, O.; Wedler, H.; Wenzel, U.; Wesner, F.; Wolf, R.; Wunderlich, R.; Zasche, D.; Zehetbauer, T.; Zehrfeld, H.-P.

    1996-12-01

    Tungsten-coated tiles, manufactured by plasma spray on graphite, were mounted in the divertor of the ASDEX Upgrade tokamak and cover almost 90% of the surface facing the plasma in the strike zone. Over 600 plasma discharges have been performed to date, around 300 of which were auxiliary heated with heating powers up to 10 MW. The production of tungsten in the divertor was monitored by a W I line at 400.8 nm. In the plasma centre an array of spectral lines at 5 nm emitted by ionization states around W XXX was measured. From the intensity of these lines the W content was derived. Under normal discharge conditions W-concentrations around 0741-3335/38/12A/013/img12 or even lower were found. The influence on the main plasma parameters was found to be negligible. The maximum concentrations observed decrease with increasing heating power. In several low power discharges accumulation of tungsten occurred and the temperature profile was flattened. The concentrations of the intrinsic impurities carbon and oxygen were comparable to the discharges with the graphite divertor. Furthermore, the density and the 0741-3335/38/12A/013/img13 limits remained unchanged and no negative influence on the energy confinement or on the H-mode threshold was found. Discharges with neon radiative cooling showed the same behaviour as in the graphite divertor case.

  18. Supersonic molecular beam fuelling at ASDEX upgrade

    International Nuclear Information System (INIS)

    The supersonic molecular beam injection (SBMI), is a fuelling technique that has been developed at Tore-Supra. This technique is based on the fast expansion of a small volume of deuterium at high pressure (typically 2-5 bars) through a nozzle into the plasma chamber. Results obtained in limiter configuration look promising: enhanced fuelling efficiency (defined as the increase in plasma particle content divided by the number of injected particles) compared to gas puff, in the range 30-50% range, have been observed. Recently one SBMI has been implemented in the divertor tokamak ASDEX upgrade in order to assess the fuelling potential of the technique. The comparison of these results with those obtained in Tore-Supra with the same hardware leads to the following conclusion: the impact of the SBMI on the plasma is much weaker. The main reason comes from the difference in the amount of particle involved per pulse that is in fact limited for technical reasons. The fuelling efficiency reaches 30% in L-mode and low density H-mode plasmas and is reduced to less than 15% in high density H-mode discharges. The amount of particle per pulse was about 10-15% of the plasma content leading to a small edge perturbation, smaller than a typical type-I ELM. A significant increase in the beam flux could improve the beam penetration and consequently the fuelling efficiency by a stronger edge cooling but the impact of such a perturbation on the confinement is still to assess. (A.C.)

  19. Control Processes and Machine Protection on ASDEX Upgrade

    International Nuclear Information System (INIS)

    ASDEX Upgrade's new real-time discharge control system connects to all coils, heating and fuelling actuators, to protection systems, and to a large number of real-time diagnostics. It evaluates and monitors many physics quantities and provides an overall plant and plasma state, to execute coordinated feedback processes, and operate actuators with advanced strategies in high performance plasma scenarios. The control system can react to specific plasma and plant states with new control goals, expressed through alternate sets of discharge schedule references, or through new references computed in real-time. The method provides extreme flexibility to respond with context-specific control strategies to optimize plasma performance, reduce the criticality of a discharge or minimize machine stress. This ability gives the control system a key role in ASDEX Upgrade's three-layer protection hierarchy, where the most flexible protection level is fully computer-based. We will sketch the control process model's features to support safety critical applications, such as self-monitoring, automatic alarm propagation and watchdog monitoring, give an overview of the plant and plasma monitor processes, show how these are mapped to the protection layers of ASDEX Upgrade, and explain the control system's activities within these. (author)

  20. 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].

  1. Operation of ASDEX Upgrade with high-Z wall coatings

    International Nuclear Information System (INIS)

    The material for plasma facing components of a future fusion device is still not decided. At present most experiments use graphite, because of its good thermo mechanical properties and the low radiation potential of carbon. Due to the high erosion yield and, especially, due to the codeposition with tritium, its use in a fusion reactor is still questionable. Based on the good experience using tungsten as divertor material in ASDEX Upgrade, which demonstrated that a divertor tokamak can be operated with a tungsten divertor without reduction of the performance, a step by step strategy was followed. Main sources of the carbon are predicted at the inner heat shield, which covers the central column. Tungsten test tiles confirm the erosion at this position due to charge exchange neutral, but also a non negligible ion sputtering component. A first step was done by siliconisation. In ASDEX Upgrade the maximal silicon concentration was 0.002. Consequently the performance of the experiment was not influenced by silicon radiation. A second step was done by tungsten coating of 1.2m2 of the inner heat shield. Experiments are done without subsequent wall coating, which would cover the tungsten. Spectroscopically measured central tungsten densities are always below ∼5*10-6 and mostly below the detection limit. Again no influence on the plasma performance parameters are found. Extrapolation to ITER conditions yields concentrations, which will not prohibit successful operation. The next step in ASDEX Upgrade will be a mostly tungsten covered inner heat shield at the next experimental campaign. (author)

  2. Destabilisation of TAE modes using ICRH in ASDEX Upgrade

    International Nuclear Information System (INIS)

    In ASDEX Upgrade, toroidicity induced Alfven eigenmodes (TAEs) are destabilised by ICRH in conventional and advanced scenarios, at low density. Most unstable TAEs have toroidal modes numbers (n=3,4,5,6) and experiments with reversed current and magnetic field showed that the TAE propagate in the current direction. On one hand, the analysis of the unstable TAE in ASDEX Upgrade shows that the data is consistent with the results from previous studies performed in other tokamaks. In particular, the measured TAE frequency, in the range (150-200kHz), is consistent with theoretical TAE frequency calculated for the parameters of the discharges performed in these experiments. On the other hand, some interesting new features have also been observed in the ASDEX Upgrade data. TAE (n=-1) was observed, which propagates in the opposite direction to the plasma current. It was also concluded that plasma rotation is insufficient to explain the experimentally observed frequency differences between two adjacent toroidal mode numbers. The measured relative fluctuation amplitude of the TAE eigenfunction in the soft X-rays channels increases towards the plasma edge. These results are consistent with the ideal MHD calculations and show that the TAE are of a global nature and not core localised TAE modes. These results are particularly important, because the radial extent of AE is a key factor in the redistribution of the energetic ions in the presence of unstable TAE. In advanced Tokamak scenarious, no evidence of Alfven Cascades was observed in experiments with ICRH minority heating in the early phase of the discharge. The effect of Electron Cyclotron Current Drive (ECCD) on the TAE amplitude was studied by applying different levels of ECCD in similar plasma configurations, with equivalent ICRH power. It was observed that ECCD has a slight destabilizing effect on the TAE. (author)

  3. Recent ASDEX Upgrade research in support of ITER and DEMO

    DEFF Research Database (Denmark)

    Zohm, H.; Ahn, J.; Aho-Mantila, L.;

    2015-01-01

    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...... in the all-tungsten (all-W) ASDEX Upgrade due to the observed poor confinement at low βN. This is mainly due to a degraded pedestal performance and hence investigations at shifting the operational point to higher βN by lowering the current have been started. At higher q95, pedestal performance can be...

  4. Recent results of reflectometry on ASDEX-upgrade

    International Nuclear Information System (INIS)

    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.)

  5. Control processes and machine protection on ASDEX Upgrade

    International Nuclear Information System (INIS)

    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

  6. Tolerable ELMs in conventional and advanced scenarios at ASDEX upgrade

    International Nuclear Information System (INIS)

    Recent ASDEX Upgrade experiments have integrated benign type II ELMs exhibiting tolerable peak heat loads on the target plates with high plasma performance in terms of confinement, beta, and density. In both conventional and advanced H-modes, the operation window with type II ELMs was extended down to q95 ∼ 3.5 in close to double null configurations at sufficiently high edge pedestal density above 50% of the Greenwald density. Type I ELMs are suppressed at almost constant pedestal parameters and confinement levels, presumably due to a change in edge stability provided by higher edge magnetic shear. Since conventional reactor designs are optimised at q95 ∼ 3, operation with type II ELMs has to compensate the required higher q-value by enhanced performance. This was achieved in H-mode scenarios with high βN > 3.5, improved confinement (H98-P ∼ 1.3), and averaged densities of 90% of Greenwald density allowing for type II ELMs. In this integrated scenario with a high triangular plasma shape the confinement is improved via peaked density profiles. Active triggering and mitigation of type I ELMs by means of hydrogen pellet injection was demonstrated with enhancement of the ELM frequency to the pellet rate of 20 Hz. The enhanced Dα (EDA) mode was not reproducible at ASDEX Upgrade. (author)

  7. Recent ASDEX Upgrade research in support of ITER and DEMO

    Science.gov (United States)

    H. Zohmthe ASDEX Upgrade Team; the EUROfusion MST1 Team

    2015-10-01

    Recent experiments on the ASDEX Upgrade tokamak aim at improving the physics base for ITER and DEMO to aid the machine design and prepare efficient operation. Type I edge localized mode (ELM) mitigation using resonant magnetic perturbations (RMPs) has been shown at low pedestal collisionality (νped\\ast discharge. Disruption mitigation studies using massive gas injection (MGI) can show an increased fuelling efficiency with high field side injection, but a saturation of the fuelling efficiency is observed at high injected mass as needed for runaway electron suppression. Large locked modes can significantly decrease the fuelling efficiency and increase the asymmetry of radiated power during MGI mitigation. Concerning power exhaust, the partially detached ITER divertor scenario has been demonstrated at Psep/R = 10 MW m-1 in ASDEX Upgrade, with a peak time averaged target load around 5 MW m-2, well consistent with the component limits for ITER. Developing this towards DEMO, full detachment was achieved at Psep/R = 7 MW m-1 and stationary discharges with core radiation fraction of the order of DEMO requirements (70% instead of the 30% needed for ITER) were demonstrated. Finally, it remains difficult to establish the standard ITER Q = 10 scenario at low q95 = 3 in the all-tungsten (all-W) ASDEX Upgrade due to the observed poor confinement at low βN. This is mainly due to a degraded pedestal performance and hence investigations at shifting the operational point to higher βN by lowering the current have been started. At higher q95, pedestal performance can be recovered by seeding N2 as well as CD4, which is interpreted as improved pedestal stability due to the decrease of bootstrap current with increasing Zeff. Concerning advanced scenarios, the upgrade of ECRH power has allowed experiments with central ctr-ECCD to modify the q-profile in improved H-mode scenarios, showing an increase in confinement at still good MHD stability with flat elevated q-profiles at values

  8. Disruption prediction with adaptive neural networks for ASDEX Upgrade

    International Nuclear Information System (INIS)

    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.

  9. Real time capable infrared thermography for ASDEX Upgrade

    Science.gov (United States)

    Sieglin, B.; Faitsch, M.; Herrmann, A.; Brucker, B.; Eich, T.; Kammerloher, L.; Martinov, S.

    2015-11-01

    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.

  10. 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.

  11. 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.

  12. Disruption prediction with adaptive neural networks for ASDEX Upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Cannas, B.; Fanni, A. [Electrical and Electronic Engineering Dept., University of Cagliari, Piazza D' Armi, 09123 Cagliari (Italy); Pautasso, G. [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, Garching (Germany); Sias, G., E-mail: giuliana.sias@diee.unica.it [Electrical and Electronic Engineering Dept., University of Cagliari, Piazza D' Armi, 09123 Cagliari (Italy)

    2011-10-15

    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.

  13. Real time capable infrared thermography for ASDEX Upgrade

    International Nuclear Information System (INIS)

    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

  14. Experiment planning and execution workflow at ASDEX Upgrade

    International Nuclear Information System (INIS)

    We present the current workflow from experiment proposals to the actual execution and evaluation of discharges at the ASDEX Upgrade tokamak. Requests for experiments are solicited from both within the IPP and from external collaborators in the yearly call-for-proposals, checked for feasibility and compliance with the project's research goals and collected in a proposal database. During the campaign shot requests are derived from the proposals and in weekly operation meetings the requests are mapped to a schedule (shot list). Before the execution of discharges a complete set of configuration data needs to be assembled. After the execution follows the analysis (including the evaluation of the discharge as to its usefulness for the underlying proposal) and logging of the attained parameters in a physics logbook. The paper describes processes, software tools, and information management showing how they ultimately lead to an improved scientific productivity.

  15. Prediction of disruptions on ASDEX Upgrade using discriminant analysis

    International Nuclear Information System (INIS)

    In this paper, a set of simple predictive criteria, each optimized for a given type of disruption, is explored. Disruptions that occurred in the years from 2005 to 2009 in the ASDEX Upgrade tokamak are classified into several types in a first step. Then, discriminant analysis is used as the main approach to the disruption prediction and a log-linear discriminant function, constructed with five global plasma parameters that have been selected from an initial group of ten variables, is derived for the edge cooling disruptions. The function is tested off-line over 308 discharges and is shown to work reliably. It describes a clear dependence of the disruption boundary on the plasma parameters.

  16. Carbon deposition and deuterium inventory in ASDEX Upgrade

    International Nuclear Information System (INIS)

    Carbon erosion and deposition in the ASDEX Upgrade divertor was investigated using a poloidal section of marked divertor tiles and silicon samples below the divertor structure. The whole inner divertor is a net carbon deposition area, while a large fraction of the outer divertor is erosion dominated and the roof baffle tiles show a complicated distribution of erosion and deposition areas. In total, 43.7 g B+C were redeposited, of which 88% were deposited on tiles and 9% in remote areas (below roof baffle, on vessel wall structures). Identified carbon sources in the main chamber are too low by a factor of ten to explain the observed carbon divertor deposition, but carbon erosion is observed at the outer divertor tiles. Deuterium is trapped mainly on the surfaces of the inner divertor tiles. The long term retention in codeposited hydrocarbon layers is about 3% of the total deuterium fuel input. (author)

  17. First results of ion cyclotron resonance heating on ASDEX upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Noterdaeme, J.; Hoffmann, C.; Brambilla, M.; Buechl, K.; Eberhagen, A.; Field, A.; Fuchs, C.; Gehre, O.; Gernhardt, J.; Gruber, O.; Haas, G.; Hermann, A.; Hofmeister, F.; Kallenbach, A.; Lieder, G.; Mertens, V.; Murmann, H.; de Pena Hempel, S.; Poschenrieder, W.; Richter, T.; Ryter, F.; Salmon, N.; Salzmann, H.; Schneider, W.; Wesner, F.; Zehrfeld, H.; Zohm, H. (Max-Planck-Institute for Plasmaphysics, D-8046 Garching (Germany)); ASDEX Upgrade Team

    1994-10-15

    ASDEX Upgrade is equipped with an ICRH system consisting of 4 generators of 2 MW power each and 4 double loop antennas. The generators, tuneable in frequency from 30 to 120 MHz, cover several heating scenarios over a wide range of magnetic fields (1 T[lt]B[sub t][lt]3.9 T): minority heating of H and He[sub 3] and second harmonic heating of H and D. ICRH-heated discharges in ASDEX Upgrade were so far carried out mainly at 30 MHz and a magnetic field of 2 T (H minority in D and He). Peak powers of 2.4 MW and pulse length up to 2.5 s were achieved (total energy 3.75 MJ). In L-mode, the density on turn-on of the ICRH stays constant, or even decreases. The ratio of radiated power to total input power is unchanged (60% in an unboronized machine, 30% in a freshly boronized machine) between Ohmic and ICRH phases. The electron temperature increases with 0.9 MW from 1 to 1.25 keV, the loop voltage drops. Transitions to the H-mode were easily and reliably achieved with ICRH alone (necessary ICRH power as low as 0.9 MW) and the length of the ELMy H-mode phases was limited only by the applied ICRH pulse length (ELMy H-mode phases of up to 2 s were achieved). The paper presents further results on heating and confinement in L and H-mode, antenna and edge studies and on divertor measurements. Preliminary experiments, performed with a combination of H minority heating (30 MHz) and H second harmonic (60 MHz) in 600 kA He and D discharges (H minority in the 5 to 20% range) at 2 T, and with non-resonant heating (30 MHz and 60 MHz at 1.35 T) are briefly discussed.

  18. Modelling and experiments on NTM stabilisation at ASDEX upgrade

    International Nuclear Information System (INIS)

    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

  19. 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

  20. 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 ...

  1. Multivariate statistical models for disruption prediction at ASDEX Upgrade

    International Nuclear Information System (INIS)

    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

  2. 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.

  3. Simulations of global electrostatic microinstabilities in ASDEX Upgrade discharges

    Science.gov (United States)

    Bottino, A.; Peeters, A. G.; Sauter, O.; Vaclavik, J.; Villard, L.

    2004-01-01

    Electrostatic microinstabilities in ion internal barrier (ITB) and H-mode discharges of the ASDEX Upgrade tokamak [O. Gruber, R. Arslanbekov, C. Atanasiu et al., Nucl. Fusion 41, 1369 (2001)] have been investigated with a full radius gyrokinetic code. The code models linear stability and includes the effect of an equilibrium radial electric field and trapped electrons. In order to simulate plasmas in experimental conditions [k⊥ρL˜O(1)], the long wavelength approximation in the quasineutrality equation has been replaced by a Padé expansion of the modified Bessel function. Results show that the E×B flow, induced by the radial electric field, changes the linear stability of the dominant ion temperature gradient modes. The electrostatic potential eddies are tilted by the sheared flow thus reducing the radial extent and the growth rate of modes. However, the finite value of the flow has a stabilizing effect too; the most unstable modes are shifted away from the unfavorable curvature region leading to lower linear growth rates. In addition to this at least two other mechanisms give an important contribution to the stabilization in the ITB region; the reverse shear profile itself and, to a lesser degree, the local value of the temperature ratio, τ=Te/Ti.

  4. Simulations of global electrostatic microinstabilities in ASDEX Upgrade discharges

    International Nuclear Information System (INIS)

    Electrostatic microinstabilities in ion internal barrier (ITB) and H-mode discharges of the ASDEX Upgrade tokamak [O. Gruber, R. Arslanbekov, C. Atanasiu et al., Nucl. Fusion 41, 1369 (2001)] have been investigated with a full radius gyrokinetic code. The code models linear stability and includes the effect of an equilibrium radial electric field and trapped electrons. In order to simulate plasmas in experimental conditions [kperpendicularρL∼O(1)], the long wavelength approximation in the quasineutrality equation has been replaced by a Pade expansion of the modified Bessel function. Results show that the ExB flow, induced by the radial electric field, changes the linear stability of the dominant ion temperature gradient modes. The electrostatic potential eddies are tilted by the sheared flow thus reducing the radial extent and the growth rate of modes. However, the finite value of the flow has a stabilizing effect too; the most unstable modes are shifted away from the unfavorable curvature region leading to lower linear growth rates. In addition to this at least two other mechanisms give an important contribution to the stabilization in the ITB region; the reverse shear profile itself and, to a lesser degree, the local value of the temperature ratio, τ=Te/Ti

  5. Propagation of cold pulses and heat pulses in ASDEX Upgrade

    International Nuclear Information System (INIS)

    Experiments on electron heat transport were performed in the tokamak ASDEX Upgrade, mainly in ohmically heated plasmas, applying either edge cooling by impurity injection or edge heat pulses with ECH. Repetitive pulses within one plasma discharge were made allowing Fourier transformation of the temperature perturbation. This yields a good signal to noise ratio up to high harmonics and allows a detailed investigation of the pulse propagation. For densities lower than 1.8x1019m-3, an increase of the central electron temperature was found as the response to the edge cooling via impurity injection similar to observations made in other tokamaks. The inversion does not appear instantaneously, but with a time delay roughly compatible with diffusion. Modeling of the propagation of the cold pulses in the framework of the IFS-PPPL model yields qualitative agreement. However the predicted increase of the ion temperature is not observed experimentally on the fast time scale. The response to ECH heat pulses is not perfectly symmetrical to cold pulse experiments, but the similarities suggest a common underlying physical mechanism. No inversion of the heat pulse is found, instead the initial pulse from the edge is associated with a second, much slower heat pulse in the centre which is similar (and not symmetrical) to that of the cold pulses. It is found that the central increase is related to the arrival of the pulse close to the inversion radius and not to the initial pulse. (author)

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

    International Nuclear Information System (INIS)

    Experiments in tokamaks suggest that a critical gradient length may cause the resilient behavior of Te 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/LTe when Te>Ti and Te≤Ti. For Te>Ti linear stability analyses indicate that electron heat transport is dominated by TEM modes. They agree in the value of the threshold (both Te and ne) 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 Te∼Ti discharges above the threshold the resilience, normalized by Te3/2 , 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)

  7. Poloidal asymmetries of heavy impurities in the ASDEX upgrade plasma

    International Nuclear Information System (INIS)

    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 highly importance an effort is launched to experimentally characterize the asymmetries comparing them with theoretical expectations. In the ASDEX upgrade tokamak (AUG) is routinely observed increase of outboard tungsten density in fast rotating plasma. This asymmetry is caused by the centrifugal force pushing tungsten ions outward due to its high mass. Furthermore, the high charge makes heavy impurities sensitive to poloidal variations of the plasma potential. The variation can be generated by magnetic trapped ions heated by RF heating. In such a case, the presence of an inboard asymmetry or at least the absence of an outboard asymmetry due to the centrifugal force can be observed. Finally, ion-impurity friction enhanced by the large charge of the impurity ions may cause a relatively weak up-down asymmetry of the impurity density. The aim of this poster is to show first evidence of these asymmetries in the AUG plasmas, the description of the used methodology, and to compare with theoretical models based on the parallel force balance.

  8. Progress in controlling ICRF-edge interactions in ASDEX upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Bobkov, Vl., E-mail: bobkov@ipp.mpg.de; Ochoukov, R.; Bilato, R.; Braun, F.; Carralero, D.; Dux, R.; Faugel, H.; Fünfgelder, H.; Jacquot, J.; Lunt, T.; Potzel, S.; Pütterich, Th. [Max-Planck-Institut für Plasmaphysik, Boltzmannstr.2, D-85748 (Germany); Jacquet, Ph.; Monakhov, I. [CCFE, Culham Science Centre, Abingdon, OX14 3DB (United Kingdom); Zhang, W.; Noterdaeme, J.-M.; Stepanov, I. [Max-Planck-Institut für Plasmaphysik, Boltzmannstr.2, D-85748 (Germany); Department of Applied Physics, Gent University, 9000 Gent (Belgium); Colas, L.; Meyer, O. [CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France); Czarnecka, A. [Institute of Plasma Physics and Laser Microfusion, Hery 23 Str., 01-497 Warsaw (Poland); and others

    2015-12-10

    RF measurements during variation of the strap voltage balance of the original 2-strap ICRF antenna in ASDEX Upgrade at constant power are consistent with electromagnetic calculations by HFSS and TOPICA, more so for the latter. RF image current compensation is observed at the antenna limiters in the experiment at a local strap voltage of about half of the value of the remote strap, albeit with a non-negligible uncertainty in phasing. The RF-specific tungsten (W) source at the broad-limiter 2-strap antenna correlates strongly with the RF voltage at the local strap at the locations not connected to opposite side of the antenna along magnetic field lines. The trends of the observed increase of the RF loading with injection of local gas are well described by a combined EMC3-Eirene – FELICE calculations, with the most efficient improvement confirmed for the outer-midplane valves, but underestimated by about 1/3. The corresponding deuterium density tailoring is also likely responsible for the decrease of local W sources observed in the experiment.

  9. Carbon influx studies in the main chamber of ASDEX Upgrade

    International Nuclear Information System (INIS)

    Carbon sources in the main chamber of ASDEX Upgrade, especially the 12 guard limiters at the low field side (LFS), were determined spectroscopically using recently installed lines of sight. Absolute photon fluxes were measured for spectral lines in the visible wavelength range referring to all spin systems of C+1 and C+2. A simple transport model for carbon enabled the simulation of the radial distribution of carbon radiation and the determination of the effective inverse photon efficiency, which was used for the evaluation of ion fluxes. The model also predicts the fraction of eroded particles that are transported out of the plasma before further ionization occurs. Comparison of the calculated losses with measurements showed good agreement in L-mode cases, whereas in H-mode cases the CIII/CII radiation ratio was too high by a factor 1.5. The contribution of each spin system to the ion flux was independently measured. For C+1 and C+2 the spin system distribution was found to be close to equilibrium. The line-of-sight-integrated photon fluxes were spatially separated for many lines of sight by Zeeman-analysis and differential measurements. This allowed us to determine the total influx from the high field side and LFS. Surprisingly, the carbon source at the inner heat shield was larger than the carbon influx from the limiter source at the LFS. This is very pronounced for the H-mode case investigated, where 60-80% of the carbon atoms emerge from the heat shield. This source is due to recycling or re-erosion of carbon, which probably originates from the limiters, because approximately 85% of the heat shield area consisted of tungsten coated tiles

  10. Carbon influx studies in the main chamber of ASDEX Upgrade

    Science.gov (United States)

    Pütterich, T.; Dux, R.; Gafert, J.; Kallenbach, A.; Neu, R.; Pugno, R.; Yoon, S. W.; ASDEX Upgrade Team

    2003-10-01

    Carbon sources in the main chamber of ASDEX Upgrade, especially the 12 guard limiters at the low field side (LFS), were determined spectroscopically using recently installed lines of sight. Absolute photon fluxes were measured for spectral lines in the visible wavelength range referring to all spin systems of C+1 and C+2. A simple transport model for carbon enabled the simulation of the radial distribution of carbon radiation and the determination of the effective inverse photon efficiency, which was used for the evaluation of ion fluxes. The model also predicts the fraction of eroded particles that are transported out of the plasma before further ionization occurs. Comparison of the calculated losses with measurements showed good agreement in L-mode cases, whereas in H-mode cases the CIII/CII radiation ratio was too high by a factor 1.5. The contribution of each spin system to the ion flux was independently measured. For C+1 and C+2 the spin system distribution was found to be close to equilibrium. The line-of-sight-integrated photon fluxes were spatially separated for many lines of sight by Zeeman-analysis and differential measurements. This allowed us to determine the total influx from the high field side and LFS. Surprisingly, the carbon source at the inner heatshield was larger than the carbon influx from the limiter source at the LFS. This is very pronounced for the H-mode case investigated, where 60-80% of the carbon atoms emerge from the heatshield. This source is due to recycling or re-erosion of carbon, which probably originates from the limiters, because ap85% of the heatshield area consisted of tungsten coated tiles.

  11. ASDEX-upgrade poloidal field coils. Specifications, load, stress. Pt. 1

    International Nuclear Information System (INIS)

    The pulsed and irregular load of the ASDEX-Upgrade poloidal field coils postulates a careful analysis of the maximum stresses in order to find out the criteria for specifications and supervision. For operating conditions known at the time of coil design, maximum stresses and loads are compiled and the resulting features and limitations of coil operation are explained. (orig.)

  12. Fast ion millimeter wave collective Thomson scattering diagnostics on TEXTOR and ASDEX upgrades

    DEFF Research Database (Denmark)

    Michelsen, S.; Korsholm, Søren Bang; Bindslev, H.; Meo, F.; Michelsen, Poul; Tsakadze, E.L.; Egedal, J.; Woskov, P.; Hoekzema, J.A.; Leuterer, F.; Westerhof, E.

    2004-01-01

    Collective Thomson scattering (CTS) diagnostic systems for measuring fast ions in TEXTOR and ASDEX Upgrade are described in this article. Both systems use millimeter waves generated by gyrotrons as probing radiation and the scattered radiation is detected with heterodyne receivers having 40...

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

    NARCIS (Netherlands)

    Garcia-Munoz, M.; 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

  14. 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 diele

  15. 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 profil...

  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 poten...

  17. 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...

  18. 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...

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

    International Nuclear Information System (INIS)

    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 χ2-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

  20. Tungsten transport in the plasma edge at ASDEX upgrade

    International Nuclear Information System (INIS)

    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

  1. 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

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

    International Nuclear Information System (INIS)

    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)

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

    International Nuclear Information System (INIS)

    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 1x1018 W-atoms cm-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.

  4. 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.

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

    International Nuclear Information System (INIS)

    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

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

    International Nuclear Information System (INIS)

    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.

  7. A Probe Head for Simultaneous Measurements of Electrostatic and Magnetic Fluctuations in ASDEX Upgrade Edge Plasma

    DEFF Research Database (Denmark)

    Schrittwieser, R W; Ionita, C; Vianello, N;

    2010-01-01

    For ASDEX Upgrade (AUG) a new probe head was developed for simultaneous measurements of electric and magnetic fluctuations in the edge plasma region. The probe head consists of a cylindrical graphite case. On the front side six graphite pins are mounted. With this arrangement the poloidal and...... is inserted up to three times for 100 ms each by the midplane manipulator into the scrape-off layer. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim....

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

    Energy Technology Data Exchange (ETDEWEB)

    Meisl, Gerd Korbinian

    2015-01-12

    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.

  9. Untersuchung der Struktur und Dynamik magnetischer Inseln im Tokamak ASDEX Upgrade

    OpenAIRE

    Meskat, John Patrick

    2001-01-01

    Neoklassische Tearing Moden begrenzen das maximale beta in magnetisch eingeschlossenen Fusionsplasmen. In dieser Arbeit werden die Struktur und Dynamik von Tearing Moden und magnetischen Inseln in ASDEX Upgrade theoretisch und experimentell untersucht. Die magnetische Struktur wird mit realistischen helikalen magnetischen Flüssen modelliert. Als Störfluß dient eine analytische Anpassungsfunktion an Lösungen der Tearing-Mode-Gleichung. Das resultierende Temperaturprofil kann mit der Wärmele...

  10. 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; Korsholm, Søren Bang; Leipold, Frank; McDermott, R. M.; Michelsen, Poul; Rasmussen, Jesper; Salewski, Mirko; Schubert, Martin; Stober, J.; Wagner, D. H.

    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...... 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....

  11. Characterization of dust collected after plasma operation of all-tungsten ASDEX Upgrade

    International Nuclear Information System (INIS)

    This work presents results of the characterization of dust collected in ASDEX Upgrade, with special emphasis on the size, morphology, structure and composition of the dust particles. The dust particles were collected after the 2009 campaign using the filtered vacuum technique. The structure and composition of the particles were examined by scanning electron microscopy combined with energy-dispersive x-ray spectroscopy, focused ion beam and scanning transmission electron microscopy with special interest in the tungsten particles. (paper)

  12. Improved Collective Thomson Scattering measurements of fast ions at ASDEX Upgrade

    DEFF Research Database (Denmark)

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

    2014-01-01

    Understanding the behaviour of the confined fast ions is important in both current and future fusion experiments. These ions play a key role in heating the plasma and will be crucial for achieving conditions for burning plasma in next-step fusion devices. Microwave-based Collective Thomson Scatte...... ASDEX Upgrade are now feasible. The new background subtraction technique could be important for the design of CTS systems in other fusion experiments....

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

    DEFF Research Database (Denmark)

    Mehlmann, F.; Schrittwieser, R.; 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)....

  14. Modelling of carbon transport in the outer divertor plasma of ASDEX upgrade

    International Nuclear Information System (INIS)

    Carbon transport in the ASDEX Upgrade outer divertor plasma is investigated in numerical simulations. The SOLPS5.0 code package is used to model the scrape-off layer plasma in a set of repeated lower-single-null L-mode discharges. Special emphasis is given to replicate the plasma conditions measured in the full tungsten, vertical outer target of ASDEX Upgrade, and solutions with and without the effect of drifts are presented. First ERO simulations of hydrocarbon transport in a SOLPS plasma background including drifts are carried out, and significantly closer match to the experimental 13C deposition pattern is obtained than with the solution without drifts. The 2D divertor electric field predicted by SOLPS is applied to the ERO modelling, and it is observed to result in a poloidal hydrocarbon drift that agrees well with the experiment. An increased carbon deposition efficiency, particularly upstream from the source, is obtained in the normal ASDEX Upgrade field configuration (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

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

    International Nuclear Information System (INIS)

    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

  16. Dual array 3D electron cyclotron emission imaging at ASDEX Upgrade.

    Science.gov (United States)

    Classen, I G J; Domier, C W; Luhmann, N C; Bogomolov, A V; Suttrop, W; Boom, J E; Tobias, B J; Donné, A J H

    2014-11-01

    In a major upgrade, the (2D) electron cyclotron emission imaging diagnostic (ECEI) at ASDEX Upgrade has been equipped with a second detector array, observing a different toroidal position in the plasma, to enable quasi-3D measurements of the electron temperature. The new system will measure a total of 288 channels, in two 2D arrays, toroidally separated by 40 cm. The two detector arrays observe the plasma through the same vacuum window, both under a slight toroidal angle. The majority of the field lines are observed by both arrays simultaneously, thereby enabling a direct measurement of the 3D properties of plasma instabilities like edge localized mode filaments. PMID:25430246

  17. Dual array 3D electron cyclotron emission imaging at ASDEX Upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Classen, I. G. J., E-mail: I.G.J.Classen@differ.nl; Bogomolov, A. V. [FOM-Institute DIFFER, Dutch Institute for Fundamental Energy Research, 3430 BE Nieuwegein (Netherlands); Domier, C. W.; Luhmann, N. C. [Department of Applied Science, University of California at Davis, Davis, California 95616 (United States); Suttrop, W.; Boom, J. E. [Max-Planck-Institut für Plasmaphysik, Boltzmannstraße 2, 85748 Garching (Germany); Tobias, B. J. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540 (United States); Donné, A. J. H. [FOM-Institute DIFFER, Dutch Institute for Fundamental Energy Research, 3430 BE Nieuwegein (Netherlands); Department of Applied Physics, Eindhoven University of Technology, 5600 MB Eindhoven (Netherlands)

    2014-11-15

    In a major upgrade, the (2D) electron cyclotron emission imaging diagnostic (ECEI) at ASDEX Upgrade has been equipped with a second detector array, observing a different toroidal position in the plasma, to enable quasi-3D measurements of the electron temperature. The new system will measure a total of 288 channels, in two 2D arrays, toroidally separated by 40 cm. The two detector arrays observe the plasma through the same vacuum window, both under a slight toroidal angle. The majority of the field lines are observed by both arrays simultaneously, thereby enabling a direct measurement of the 3D properties of plasma instabilities like edge localized mode filaments.

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

    International Nuclear Information System (INIS)

    LabVIEW is a valuable tool for building multi-core multi-threaded application using commercial off the shelf components, FPGAs and third party hardware for real time diagnostics on ASDEX tokamak upgrade. 5 real time labVIEW RT diagnostics in operation with connection to UDP/XML framework of the ASDEX control system are presented in this poster: 1) real time flux surfaces, 2) vacuum field calculations, 3) halo currents, 4) bolometer and 5) manometer

  19. Status, Operation, and Extension of the ECRH System at ASDEX Upgrade

    Science.gov (United States)

    Wagner, D.; Stober, J.; Leuterer, F.; Monaco, F.; Müller, S.; Münich, M.; Rapson, C. J.; Reich, M.; Schubert, M.; Schütz, H.; Treutterer, W.; Zohm, H.; Thumm, M.; Scherer, T.; Meier, A.; Gantenbein, G.; Jelonnek, J.; Kasparek, W.; Lechte, C.; Plaum, B.; Goodman, T.; Litvak, A. G.; Denisov, G. G.; Chirkov, A.; Zapevalov, V.; Malygin, V.; Popov, L. G.; Nichiporenko, V. O.; Myasnikov, V. E.; Tai, E. M.; Solyanova, E. A.; Malygin, S. A.

    2016-01-01

    The upgraded electron cyclotron resonance heating (ECRH) system at ASDEX Upgrade (AUG) has been routinely used with eight gyrotrons during the last experimental campaign. A further upgrade will replace the existing system of four short-pulse (140 GHz, 2 s, 500 kW) gyrotrons. The final goal is to have around 6.5-7 MW at 140 GHz (or 5.5 MW at 105 GHz) from eight units available in the plasma during the whole AUG discharge (10 s). The system operates at 140 and 105 GHz with X2, O2 and X3 schemes. For B > 3 T also an ITER-like O1-scenario can be run using the 105 GHz option. Four of the eight launching antennas are capable of fast poloidal movements necessary for real-time control of the location of power deposition.

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

    International Nuclear Information System (INIS)

    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. ELM behaviour and linear MHD stability of edge ECRH heated ASDEX Upgrade plasmas

    Science.gov (United States)

    Burckhart, A.; Dunne, M.; Wolfrum, E.; Fischer, R.; McDermott, R.; Viezzer, E.; Willensdorfer, M.; the ASDEX Upgrade Team

    2016-05-01

    In order to test the peeling–ballooning ELM model, ECRH heating was applied to the edge of ASDEX Upgrade type-I ELMy H-mode plasmas to alter the pedestal pressure and current density profiles. The discharges were analysed with respect to ideal MHD stability. While the ELM frequency increased and the pedestal gradients relaxed with edge ECRH, the MHD stability boundary did not change. The results indicate that the peeling–ballooning model is insufficient to fully explain the triggering of ELM instabilities in the presence of edge ECRH heating.

  2. 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

    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 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...

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

    International Nuclear Information System (INIS)

    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

  5. 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.

  6. Effect of 3D magnetic perturbations on the plasma rotation in ASDEX Upgrade

    Science.gov (United States)

    Martitsch, A. F.; Kasilov, S. V.; Kernbichler, W.; Kapper, G.; Albert, C. G.; Heyn, M. F.; Smith, H. M.; Strumberger, E.; Fietz, S.; Suttrop, W.; Landreman, M.; The ASDEX Upgrade Team; the EUROfusion MST1 Team

    2016-07-01

    The toroidal torque due to the non-resonant interaction with external magnetic perturbations (TF ripple and perturbations from ELM mitigation coils) in ASDEX Upgrade is modelled with help of the NEO-2 and SFINCS codes and compared to semi-analytical models. It is shown that almost all non-axisymmetric transport regimes contributing to neoclassical toroidal viscosity (NTV) are realized within a single discharge at different radial positions. The NTV torque is obtained to be roughly a quarter of the NBI torque. This indicates the presence of other important momentum sources. The role of these momentum sources and possible integral torque balance measurements are briefly discussed.

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

    International Nuclear Information System (INIS)

    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.)

  8. Destabilization of fast particle stabilized sawteeth in ASDEX Upgrade with electron cyclotron current drive

    DEFF Research Database (Denmark)

    Igochine, V.; Chapman, I.T.; Bobkov, V.; Günter, S.; Maraschek, M.; Moseev, Dmitry; Pereversev, G.; Reich, M.; Stober, J.

    2011-01-01

    It is often observed that large sawteeth trigger the neoclassical tearing mode well below the usual threshold for this instability. At the same time, fast particles in the plasma core stabilize sawteeth and provide these large crashes. The paper presents results of first experiments in ASDEX...... Upgrade for destabilization of fast particle stabilized sawteeth with electron cyclotron current drive (ECCD). It is shown that moderate ECCD from a single gyrotron is able to destabilize the fast particle stabilized sawteeth. A reduction in sawtooth period by about 40% was achieved in first experiments...

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

    International Nuclear Information System (INIS)

    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

  10. Resolving the bulk ion region of millimeter-wave collective Thomson scattering spectra at ASDEX Upgrade

    DEFF Research Database (Denmark)

    Stejner Pedersen, Morten; Nielsen, Stefan Kragh; Jacobsen, Asger Schou; Korsholm, Søren Bang; Leipold, Frank; Meo, Fernando; Michelsen, Poul; Moseev, Dmitry; Rasmussen, Jesper; Salewski, Mirko; Schubert, M.; Stober, J.; Wagner, D. H.

    2014-01-01

    Collective Thomson scattering (CTS) measurements provide information about the composition and velocity distribution of confined ion populations in fusion plasmas. The bulk ion part of the CTS spectrum is dominated by scattering off fluctuations driven by the motion of thermalized ion populations....... It thus contains information about the ion temperature, rotation velocity, and plasma composition. To resolve the bulk ion region and access this information, we installed a fast acquisition system capable of sampling rates up to 12.5 GS/s in the CTS system at ASDEX Upgrade. CTS spectra with...... temperature, rotation velocity, and plasma composition....

  11. On-line prediction and mitigation of disruptions in ASDEX Upgrade

    International Nuclear Information System (INIS)

    An on-line predictor of the time to disruption has been installed on the ASDEX Upgrade tokamak. It is suitable either for avoidance of disruptions or for mitigation of those that are unavoidable. The prediction uses a neural network trained on eight plasma parameters and their time derivatives extracted from 99 disruptive discharges. The network was tested off-line over 500 discharges and was found to work reliably and to be able to predict the majority of the disruptions. The trained network was installed on-line, tested over 128 discharges and used to inject killer pellets to mitigate the disruption loads. (author)

  12. Supplement to 'ASDEX Upgrade, definition of a tokamak experiment with a reactor-compatible poloidal divertor' (IPP-report 1/197, March 1982)

    International Nuclear Information System (INIS)

    Since March 1982 the better understanding of the divertor physics, both by theory and experiments, and the development of the ASDEX Upgrade concept have considerably improved and simplified the ASDEX Upgrade design. Single null poloidal divertor configurations were calculated, which can well compete with elongated limiter configurations in reduced poloidal field effort. The role of recycling and its limitation set by the available energy flux, observed experimentally and explained by a plasma boundary flow model, led to a refined formulation of the line density requirements. Finally, a discussion of the attainable temperature and densities allowed clearly to distinguish between ASDEX and ASDEX Upgrade and pointed out the dominant role of the plasma current. The ASDEX Upgrade basic data are summarized as presented to the EURATOM advisory board. (orig.)

  13. Improved Collective Thomson Scattering measurements of fast ions at ASDEX upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Rasmussen, J.; Nielsen, S. K.; Stejner, M.; Salewski, M.; Jacobsen, A. S.; Korsholm, S. B.; Leipold, F.; Meo, F.; Michelsen, P. K. [Association Euratom-DTU, Technical University of Denmark, Department of Physics, DTU Riso/ Campus, DK-4000 Roskilde (Denmark); Moseev, D. [Association Euratom-FOM Institute DIFFER, 3430 BE Nieuwegein (Netherlands); Schubert, M.; Stober, J.; Tardini, G.; Wagner, D.; Collaboration: ASDEX Upgrade Team

    2014-08-21

    Understanding the behaviour of the confined fast ions is important in both current and future fusion experiments. These ions play a key role in heating the plasma and will be crucial for achieving conditions for burning plasma in next-step fusion devices. Microwave-based Collective Thomson Scattering (CTS) is well suited for reactor conditions and offers such an opportunity by providing measurements of the confined fast-ion distribution function resolved in space, time and 1D velocity space. We currently operate a CTS system at ASDEX Upgrade using a gyrotron which generates probing radiation at 105 GHz. A new setup using two independent receiver systems has enabled improved subtraction of the background signal, and hence the first accurate characterization of fast-ion properties. Here we review this new dual-receiver CTS setup and present results on fast-ion measurements based on the improved background characterization. These results have been obtained both with and without NBI heating, and with the measurement volume located close to the centre of the plasma. The measurements agree quantitatively with predictions of numerical simulations. Hence, CTS studies of fast-ion dynamics at ASDEX Upgrade are now feasible. The new background subtraction technique could be important for the design of CTS systems in other fusion experiments.

  14. Consistency between real and synthetic fast-ion measurements at ASDEX Upgrade

    Science.gov (United States)

    Rasmussen, J.; Nielsen, S. K.; Stejner, M.; Geiger, B.; Salewski, M.; Jacobsen, A. S.; Korsholm, S. B.; Leipold, F.; Michelsen, P. K.; Moseev, D.; Schubert, M.; Stober, J.; Tardini, G.; Wagner, D.; The ASDEX Upgrade Team

    2015-07-01

    Internally consistent characterization of the properties of the fast-ion distribution from multiple diagnostics is a prerequisite for obtaining a full understanding of fast-ion behavior in tokamak plasmas. Here we benchmark several absolutely-calibrated core fast-ion diagnostics at ASDEX Upgrade by comparing fast-ion measurements from collective Thomson scattering, fast-ion {{\\text{D}}α} spectroscopy, and neutron rate detectors with numerical predictions from the TRANSP/NUBEAM transport code. We also study the sensitivity of the theoretical predictions to uncertainties in the plasma kinetic profiles. We find that theory and measurements generally agree within these uncertainties for all three diagnostics during heating phases with either one or two neutral beam injection sources. This suggests that the measurements can be described by the same model assuming classical slowing down of fast ions. Since the three diagnostics in the adopted configurations probe partially overlapping regions in fast-ion velocity space, this is also consistent with good internal agreement among the measurements themselves. Hence, our results support the feasibility of combining multiple diagnostics at ASDEX Upgrade to reconstruct the fast-ion distribution function in 2D velocity space.

  15. Cooling water calorimetry measuring results from the first years of ASDEX Upgrade operation

    International Nuclear Information System (INIS)

    At the tokamak ASDEX Upgrade an extensive cooling water calorimetry system was installed. This system has measured the toroidal and poloidal distributions of the energy deposition by monitoring the temperature rise of the cooling water in 80 separate cooling units in the divertor plates and the central heat shield. The measurements show, that there exist no toroidal asymmetries in the energy deposition on the divertor plates for all kinds of ohmic discharges and for ICRH discharges with a toroidal magnetic field directed opposite to the plasma current. However, Neutral Beam Injection causes a toroidal asymmetric energy deposition profile. Furthermore the reduction of the poloidal in-out asymmetry of the energy load at the divertor plates due to magnetic field reversion was detected. Making up the general energy balance of ASDEX Upgrade, adding the energy detected by the cooling water calorimetry system and the radiation loss energy measured by the bolometry diagnostic, one gets 92%-97% of the energy input. (orig./HD)

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

    Science.gov (United States)

    Weiland, M.; Geiger, B.; Jacobsen, A. S.; Reich, M.; Salewski, M.; Odstrčil, T.; the ASDEX Upgrade Team

    2016-02-01

    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 parts of the Doppler spectrum. These improvements make it possible to reconstruct the 2D fast-ion velocity distribution f≤ft(E,{{v}\\parallel}/v\\right) 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.

  17. Validation of gyrokinetic modelling of light impurity transport including rotation in ASDEX Upgrade

    CERN Document Server

    Casson, F J; Angioni, C; Camenen, Y; Dux, R; Fable, E; Fischer, R; Geiger, B; Manas, P; Menchero, L; Tardini, G

    2013-01-01

    Upgraded spectroscopic hardware and an improved impurity concentration calculation allow accurate determination of boron density in the ASDEX Upgrade tokamak. A database of boron measurements is compared to quasilinear and nonlinear gyrokinetic simulations including Coriolis and centrifugal rotational effects over a range of H-mode plasma regimes. The peaking of the measured boron profiles shows a strong anti-correlation with the plasma rotation gradient, via a relationship explained and reproduced by the theory. It is demonstrated that the rotodiffusive impurity flux driven by the rotation gradient is required for the modelling to reproduce the hollow boron profiles at higher rotation gradients. The nonlinear simulations validate the quasilinear approach, and, with the addition of perpendicular flow shear, demonstrate that each symmetry breaking mechanism that causes momentum transport also couples to rotodiffusion. At lower rotation gradients, the parallel compressive convection is required to match the mos...

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

    NARCIS (Netherlands)

    Geiger, B.; Garcia-Munoz, M.; 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 50%-toget

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

    International Nuclear Information System (INIS)

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

    International Nuclear Information System (INIS)

    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)

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

    International Nuclear Information System (INIS)

    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)

  3. Performance measurements of the collective Thomson scattering receiver at ASDEX Upgrade

    DEFF Research Database (Denmark)

    Furtula, Vedran; Leipold, Frank; Salewski, Mirko;

    2012-01-01

    The fast-ion collective Thomson scattering (CTS) receiver at ASDEX Upgrade can detect spectral power densities of a few eV in the millimeter-wave range against the electron cyclotron emission (ECE) background on the order of 100 eV under presence of gyrotron stray radiation that is several orders...... detector diodes. The performance of the entire receiver is determined by the main receiver components operating at mm-wave frequencies (notch-, bandpass- and lowpass filters, a voltage-controlled variable attenuator, and an isolator), a mixer, and the IF components (amplifiers, band-pass filters......, and detector diodes). We discuss here the design of the entire receiver, focussing on its performance as a unit. The receiver has been disassembled, and the performance of its individual components has been characterized. Based on these individual component measurements we predict the spectral response...

  4. Consistency between real and synthetic fast-ion measurements at ASDEX Upgrade

    DEFF Research Database (Denmark)

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

    2015-01-01

    by comparing fast-ion measurements from collective Thomson scattering, fast-ion spectroscopy, and neutron rate detectors with numerical predictions from the TRANSP/NUBEAM transport code. We also study the sensitivity of the theoretical predictions to uncertainties in the plasma kinetic profiles. We find......Internally consistent characterization of the properties of the fast-ion distribution from multiple diagnostics is a prerequisite for obtaining a full understanding of fast-ion behavior in tokamak plasmas. Here we benchmark several absolutely-calibrated core fast-ion diagnostics at ASDEX Upgrade...... that theory and measurements generally agree within these uncertainties for all three diagnostics during heating phases with either one or two neutral beam injection sources. This suggests that the measurements can be described by the same model assuming classical slowing down of fast ions. Since the three...

  5. Design and performance of the collective Thomson scattering receiver at ASDEX Upgrade

    DEFF Research Database (Denmark)

    Furtula, Vedran; Salewski, Mirko; Leipold, Frank;

    2012-01-01

    Here we present the design of the fast-ion collective Thomson scattering receiver for millimeter wave radiation installed at ASDEX Upgrade, a tokamak for fusion plasma experiments. The receiver can detect spectral power densities of a few eV against the electron cyclotron emission background...... is divided into 50 IF channels tightly spaced in frequency space. The channels are terminated by square-law detector diodes that convert the signal power into DC voltages. We present measurements of the transmission characteristics and performance of the main receiver components operating at mm......-wave frequencies (notch, bandpass, and lowpass filters, a voltage-controlled variable attenuator, and an isolator), the down-converter unit, and the IF components (amplifiers, bandpass filters, and detector diodes). Furthermore, we determine the performance of the receiver as a unit through spectral response...

  6. Electric Probe Measurements of the Poloidal Velocity in the Scrape-Off Layer of ASDEX Upgrade

    DEFF Research Database (Denmark)

    Mehlmann, F.; Costea, S.; Schrittwieser, R..; Naulin, Volker; Juul Rasmussen, Jens; Müller, H.W.; Nielsen, Anders Henry; Vianello, N.; Carralero, D.; Rohde, V.; Lux, C.; Ionita, C.

    2014-01-01

    A reciprocating probe head with six pins was used for localized measurements of electric fields and densities in the scrape-off layer (SOL) of ASDEX Upgrade (AUG) up to the edge shear layer (SL) near the Last Closed Flux Surface (LCFS). The edge SL is characterized by a strong sudden change in the...... poloidal velocity v close to the separatrix. The probes were used to determine this velocity by different methods which are critically compared to each other concerning their reliability. By the first method the poloidal velocity was deduced from the radial electric field E-r measured by two radially...... staggered probe pins, with v being due to the E-r x B-phi-drift (B-phi is the toroidal field). The two other methods utilized the cross correlation of two poloidally staggered ion-biased probes and two poloidally staggered floating probes, respectively. In this case the time lags with maximum cross...

  7. Poloidal asymmetric flow and current relaxation of ballooned transport during I-phase in ASDEX Upgrade

    Science.gov (United States)

    Manz, P.; Birkenmeier, G.; Fuchert, G.; Cavedon, M.; Conway, G. D.; Maraschek, M.; Medvedeva, A.; Mink, F.; Scott, B. D.; Shao, L. M.; Stroth, U.

    2016-05-01

    Turbulence driven poloidal asymmetric parallel flow and current perturbations are studied for tokamak plasmas of circular geometry. Whereas zonal flows can lead to in-out asymmetry of parallel flows and currents via the Pfirsch-Schlüter mechanism, ballooned transport can result in an up-down asymmetry due to the Stringer spin-up mechanism. Measurements of up-down asymmetric parallel current fluctuations occurring during the I-phase in ASDEX Upgrade are not responses to the equilibrium by the Pfirsch-Schlüter current, but can be interpreted as a response to strongly ballooned plasma transport coupled with the Stringer spin-up mechanism. A good agreement of the experimental measured limit-cycle frequencies during I-phase with the Stringer spin-up relaxation frequency is found.

  8. Injection of nitrogen-15 tracer into ASDEX-Upgrade: New technique in material migration studies

    Energy Technology Data Exchange (ETDEWEB)

    Petersson, P., E-mail: Per.Petersson@ee.kth.sen [Fusion Plasma Physics, Royal Institute of Technology, Association EURATOM-VR, SE-100 44 Stockholm (Sweden); Hakola, A.; Likonen, J. [VTT, Association EURATOM-TEKES, 02044 Espoo, VTT (Finland); Mayer, M. [Max-Planck-Institut für Plasmaphysik, EURATOM Association, 85748 Garching (Germany); Miettunen, J. [Aalto University, Association EURATOM-TEKES, 00076 Aalto (Finland); Neu, R.; Rohde, V. [Max-Planck-Institut für Plasmaphysik, EURATOM Association, 85748 Garching (Germany); Rubel, M. [Fusion Plasma Physics, Royal Institute of Technology, Association EURATOM-VR, SE-100 44 Stockholm (Sweden)

    2013-07-15

    For the first time nitrogen-15 gas was used as a tracer for determining of global nitrogen retention in ASDEX-Upgrade. The injection done from the midplane gas inlet on the last day of the experimental campaign was followed by retrieval and ex situ analyses of many limiter and divertor tiles. The study was done by nuclear reaction analysis using the {sup 15}N({sup 1}H, γ{sup 4}He){sup 12}C process and detecting both γ radiation and {sup 4}He. The highest and peaked concentrations of {sup 15}N, 8 × 10{sup 16} cm{sup 2}, were found on limiters close to the injection point, while fairly homogeneous flat profiles were measured on most of the divertor plates. The measured concentrations are compared to an ASCOT simulation of the injection.

  9. Towards non-linear simulations of full ELM crashes in ASDEX upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Lessig, Alexander; Hoelzl, Matthias; Lackner, Karl; Guenter, Sibylle [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, Boltzmannstrasse 2, 85748 Garching (Germany)

    2014-07-01

    Edge localized modes (ELMs) of large size are a severe concern for the operation of ITER due to the large transient heat loads on divertor targets and wall structures. 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 Fourier spectrum and the drop of pedestal gradients are studied. In particular, we confirm a previously introduced quadratic mode coupling model for the early non-linear evolution of the mode structure and present first results concerning the evolution in the fully non-linear phase. Eventually, we aim to identify different ELM types in our simulations as observed in experiments and to compare the results to experimental observations, e.g., regarding the pedestal evolution and the heat deposition patterns. Work is ongoing to increase poloidal resolution and include diamagnetic stabilization of high mode numbers.

  10. Experimental studies and modeling of complete H-mode divertor detachment in ASDEX Upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Reimold, F., E-mail: Felix.Reimold@ipp.mpg.de [Max-Planck-Institut für Plasmaphysik, Boltzmannstraß e 2, D-85748 Garching (Germany); Wischmeier, M.; Bernert, M.; Potzel, S.; Coster, D. [Max-Planck-Institut für Plasmaphysik, Boltzmannstraße 2, D-85748 Garching (Germany); Bonnin, X. [CNRS-LSPM, Université Paris 13, Sorbonne Paris Cité, F-93430 Villetaneuse (France); Reiter, D. [Institut für Energie- und Klimaforschung – Plasmaphysik, Forschungszentrum Jülich GmbH (Germany); Meisl, G.; Kallenbach, A. [Max-Planck-Institut für Plasmaphysik, Boltzmannstraße 2, D-85748 Garching (Germany); Aho-Mantila, L. [VTT, FI-02044 VTT (Finland); Stroth, U. [Max-Planck-Institut für Plasmaphysik, Boltzmannstraße 2, D-85748 Garching (Germany)

    2015-08-15

    Power exhaust in future fusion devices is critical and operation with a detached divertor is foreseen for ITER and DEMO. The evolution of detachment in nitrogen seeded H-mode discharges at ASDEX Upgrade is categorized in four phases. Complete detachment of the outer target is found to be correlated with a strongly localized radiation at the X-point and a pressure loss at the pedestal top at almost constant core plasma pressure. SOLPS modeling shows that enhanced radial transport in the divertor region is necessary to reconcile the experimental profiles with the simulations. The modeling supports the experimental observation of the correlation of complete detachment with an X-point radiation and a reduction of the pedestal top pressure. A remaining discrepancy are significantly lower neutral densities in the divertor compared to experiment. The effects of wall pumping, the particle reflection model and the boundary conditions on the plasma solution are discussed.

  11. Erosion of tungsten and steel in the main chamber of ASDEX Upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Hakola, A., E-mail: antti.hakola@vtt.fi [VTT, P.O. Box 1000, 02044 VTT (Finland); Koivuranta, S.; Likonen, J. [VTT, P.O. Box 1000, 02044 VTT (Finland); Herrmann, A.; Maier, H.; Mayer, M. [Max-Planck-Institut für Plasmaphysik, Boltzmannstrasse 2, 85748 Garching (Germany); Neu, R. [Max-Planck-Institut für Plasmaphysik, Boltzmannstrasse 2, 85748 Garching (Germany); Technische Universität München, 85747 Garching (Germany); Rohde, V. [Max-Planck-Institut für Plasmaphysik, Boltzmannstrasse 2, 85748 Garching (Germany)

    2015-08-15

    We have investigated net erosion and deposition of W and P92 steel in ASDEX Upgrade during its full-W operational phase. The outer divertor and the outer midplane are the strongest net erosion region for W, with rates up to 0.12 nm/s and 0.05 nm/s, respectively. The eroded W is transported via the scrape-off layer plasma and predominantly deposited in the upper (20–30%) and inner divertors (40–60%). The inner midplane does not contribute significantly to the erosion–deposition balance such that the remaining W is deposited in shadowed areas of the tokamak. Steel is eroded 3–10 times faster than W but could be used at the top and inner parts of the main chamber where the erosion rate is ∼0.01 nm/s.

  12. 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.

  13. Resolving the bulk ion region of millimeter-wave collective Thomson scattering spectra at ASDEX Upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Stejner, M., E-mail: mspe@fysik.dtu.dk; Nielsen, S.; Jacobsen, A. S.; Korsholm, S. B.; Leipold, F.; Meo, F.; Michelsen, P. K.; Rasmussen, J.; Salewski, M. [Department of Physics, Association EURATOM-DTU, Technical University of Denmark, DK-2800 Kgs. Lyngby (Denmark); Moseev, D. [Max-Planck-Institut für Plasmaphysik, EURATOM-Association, Boltzmannstr. 2, 85748 Garching (Germany); Association Euratom-FOM Institute DIFFER, 3430 BE Nieuwegein (Netherlands); Schubert, M.; Stober, J.; Wagner, D. H. [Max-Planck-Institut für Plasmaphysik, EURATOM-Association, Boltzmannstr. 2, 85748 Garching (Germany)

    2014-09-15

    Collective Thomson scattering (CTS) measurements provide information about the composition and velocity distribution of confined ion populations in fusion plasmas. The bulk ion part of the CTS spectrum is dominated by scattering off fluctuations driven by the motion of thermalized ion populations. It thus contains information about the ion temperature, rotation velocity, and plasma composition. To resolve the bulk ion region and access this information, we installed a fast acquisition system capable of sampling rates up to 12.5 GS/s in the CTS system at ASDEX Upgrade. CTS spectra with frequency resolution in the range of 1 MHz are then obtained through direct digitization and Fourier analysis of the CTS signal. We here describe the design, calibration, and operation of the fast receiver system and give examples of measured bulk ion CTS spectra showing the effects of changing ion temperature, rotation velocity, and plasma composition.

  14. Non-linear simulations of ELMs in ASDEX Upgrade including diamagnetic drift effects

    Energy Technology Data Exchange (ETDEWEB)

    Lessig, Alexander; Hoelzl, Matthias; Krebs, Isabel; Franck, Emmanuel; Guenter, Sibylle [Max-Planck-Institut fuer Plasmaphysik, Boltzmannstrasse 2, 85748 Garching (Germany); Orain, Francois; Morales, Jorge; Becoulet, Marina [CEA-IRFM, Cadarache, 13108 Saint-Paul-Lez-Durance (France); Huysmans, Guido [ITER Organization, 13067 Saint-Paul-Lez-Durance (France)

    2015-05-01

    Large edge localized modes (ELMs) are a severe concern for ITER due to high transient heat loads on divertor targets and wall structures. Using the non-linear MHD code JOREK, we have performed ELM simulations for ASDEX Upgrade (AUG) including diamagnetic drift effects. The influence of diamagnetic terms onto the evolution of the toroidal mode spectrum for different AUG equilibria and the non-linear interaction of the toroidal harmonics are investigated. In particular, we confirm the diamagnetic stabilization of high mode numbers and present new features of a previously introduced quadratic mode coupling model for the early non-linear evolution of the mode structure. Preliminary comparisons of full ELM crashes with experimental observations are shown aiming at code validation and the understanding of different ELM types. Work is ongoing to include toroidal and neoclassical poloidal rotation in our simulations.

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

    International Nuclear Information System (INIS)

    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.)

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

    International Nuclear Information System (INIS)

    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 He3 minority, hydrogen fundamental and 2nd harmonic and deuterium 2nd harmonic heating. For neutral injection four JET sources with 60 keV H0 and 80 A combined in one injection box were chosen. The averaged injection angle is 240 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)

  17. Application of radial correlation doppler reflectometry on the ASDEX Upgrade tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Pinzon, J.R.; Stroth, U. [Max-Planck-Institut fuer Plasmaphysik, Boltzmannstr. 2, D-85748 Garching (Germany); Physik-Department E28, TUM, D-85748 Garching (Germany); Happel, T. [Max-Planck-Institut fuer Plasmaphysik, Boltzmannstr. 2, D-85748 Garching (Germany); Hennequin, P. [Laboratoire de Physique des Plasmas, Ecole Polytechnique (France); Collaboration: The ASDEX Upgrade Team

    2015-05-01

    Doppler Reflectometry (DR) is a diagnostic used for the characterization of plasma density turbulence in magnetic confinement devices. It allows to measure the perpendicular propagation velocity of density fluctuations and their perpendicular wavenumber spectrum with good spatial resolution. By studying the correlation between signals of two reflectometers probing at different radial positions (Radial Correlation DR), it is possible to evaluate the radial correlation length L{sub r} of the plasma turbulence by scanning the radial separation Δr. However, results from analytical calculations and two-dimensional full-wave simulations indicate that the L{sub r} measurement by RCDR is not straightforward and might depend on factors such as plasma velocity, fluctuation amplitudes and probing beam angle. Experimental data from the ASDEX Upgrade tokamak are studied. An assessment of the viability of the use of different signals and analysis methods, including an evaluation of potential caveats, is given.

  18. Non-linear modeling of the plasma response to RMPs in ASDEX Upgrade

    CERN Document Server

    Orain, F; Viezzer, E; Dunne, M; Becoulet, M; Cahyna, P; Huijsmans, G T A; Morales, J; Willensdorfer, M; Suttrop, W; Kirk, A; Pamela, S; Strumberger, E; Guenter, S; Lessig, A

    2016-01-01

    The plasma response to Resonant Magnetic Perturbations (RMPs) in ASDEX Upgrade is modeled with the non-linear resistive MHD code JOREK, using input profiles that match those of the experiments as closely as possible. The RMP configuration for which Edge Localized Modes are best mitigated in experiments is related to the largest edge kink response observed near the X-point in modeling. On the edge resonant surfaces q = m=n, the coupling between the m + 2 kink component and the m resonant component is found to induce the amplification of the resonant magnetic perturbation. The ergodicity and the 3D-displacement near the X-point induced by the resonant ampli?cation can only partly explain the density pumpout observed in experiments.

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

    International Nuclear Information System (INIS)

    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

  20. 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

  1. Automated in situ line of sight calibration of ASDEX Upgrade bolometers

    International Nuclear Information System (INIS)

    The ITER Bolometer Robot Test Rig (IBOROB) is a robot-based diagnostic tool, which allows the measurement of the lines of sight (LOS) of the ITER bolometer prototypes. Up to now, it was only used as a LOS characterization device for the ITER collimator development. IBOROB was further developed and can now be operated in ASDEX Upgrade during a regular maintenance shutdown. At present, once a diagnostic like the bolometry is mounted inside the vessel, the actual LOS orientations are not measured, they are derived from CAD. The new procedure allows the fully automatic three-dimensional in situ measurement of bolometer LOS. The spatial distribution, the poloidal and toroidal alignment in the experiment coordinate system (CS), can be determined. The absolute accuracy, in reference to the tokamak CS, is provided by an additional calibration performed with a measurement arm by FARO Technologies Inc. Therefore, the amount of misalignment from the theoretical expectations can be quantified. In addition specific camera type dependencies such as internal camera reflections can be identified. Due to the high position accuracy of the robot, the LOS can be resolved with a spatial resolution of up to 0.1°. The method is explained in detail and results from two exemplary bolometer foil cameras obtained in a first set-up in ASDEX Upgrade are presented. The different steps and components needed to apply the measurements in the vessel are described with a focus on the constraints, e.g. geometrical, for an application of this method in a tokamak. Finally the consequences of the results are extrapolated to ITER and evaluated

  2. 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

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

    International Nuclear Information System (INIS)

    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

  4. A compact lithium pellet injector for tokamak pedestal studies in ASDEX Upgrade.

    Science.gov (United States)

    Arredondo Parra, R; Moreno Quicios, R; Ploeckl, B; Birkenmeier, G; Herrmann, A; Kocsis, G; Laggner, F M; Lang, P T; Lunt, T; Macian-Juan, R; Rohde, V; Sellmair, G; Szepesi, T; Wolfrum, E; Zeidner, W; Neu, R

    2016-02-01

    Experiments have been performed at ASDEX Upgrade, aiming to investigate the impact of lithium in an all-metal-wall tokamak and attempting to enhance the pedestal operational space. For this purpose, a lithium pellet injector has been developed, capable of injecting pellets carrying a particle content ranging from 1.82 × 10(19) atoms (0.21 mg) to 1.64 × 10(20) atoms (1.89 mg). The maximum repetition rate is about 2 Hz. Free flight launch from the torus outboard side without a guiding tube was realized. In such a configuration, angular dispersion and speed scatter are low, and a transfer efficiency exceeding 90% was achieved in the test bed. Pellets are accelerated in a gas gun; hence special care was taken to avoid deleterious effects by the propellant gas pulse. Therefore, the main plasma gas species was applied as propellant gas, leading to speeds ranging from 420 m/s to 700 m/s. In order to minimize the residual amount of gas to be introduced into the plasma vessel, a large expansion volume equipped with a cryopump was added into the flight path. In view of the experiments, an optimal propellant gas pressure of 50 bars was chosen for operation, since at this pressure maximum efficiency and low propellant gas flux coincide. This led to pellet speeds of 585 m/s ± 32 m/s. Lithium injection has been achieved at ASDEX Upgrade, showing deep pellet penetration into the plasma, though pedestal broadening has not been observed yet. PMID:26931850

  5. Automated in situ line of sight calibration of ASDEX Upgrade bolometers

    Energy Technology Data Exchange (ETDEWEB)

    Penzel, F., E-mail: florian.penzel@ipp.mpg.de [Max-Planck-Institute for Plasmaphysics, EURATOM Association, Garching (Germany); Meister, H.; Bernert, M.; Sehmer, T.; Trautmann, T.; Kannamüller, M.; Koll, J. [Max-Planck-Institute for Plasmaphysics, EURATOM Association, Garching (Germany); Koch, A.W. [Institute for Measurement Systems and Sensor Technology, Technische Universität München (Germany)

    2014-10-15

    The ITER Bolometer Robot Test Rig (IBOROB) is a robot-based diagnostic tool, which allows the measurement of the lines of sight (LOS) of the ITER bolometer prototypes. Up to now, it was only used as a LOS characterization device for the ITER collimator development. IBOROB was further developed and can now be operated in ASDEX Upgrade during a regular maintenance shutdown. At present, once a diagnostic like the bolometry is mounted inside the vessel, the actual LOS orientations are not measured, they are derived from CAD. The new procedure allows the fully automatic three-dimensional in situ measurement of bolometer LOS. The spatial distribution, the poloidal and toroidal alignment in the experiment coordinate system (CS), can be determined. The absolute accuracy, in reference to the tokamak CS, is provided by an additional calibration performed with a measurement arm by FARO Technologies Inc. Therefore, the amount of misalignment from the theoretical expectations can be quantified. In addition specific camera type dependencies such as internal camera reflections can be identified. Due to the high position accuracy of the robot, the LOS can be resolved with a spatial resolution of up to 0.1°. The method is explained in detail and results from two exemplary bolometer foil cameras obtained in a first set-up in ASDEX Upgrade are presented. The different steps and components needed to apply the measurements in the vessel are described with a focus on the constraints, e.g. geometrical, for an application of this method in a tokamak. Finally the consequences of the results are extrapolated to ITER and evaluated.

  6. A compact lithium pellet injector for tokamak pedestal studies in ASDEX Upgrade

    Science.gov (United States)

    Arredondo Parra, R.; Moreno Quicios, R.; Ploeckl, B.; Birkenmeier, G.; Herrmann, A.; Kocsis, G.; Laggner, F. M.; Lang, P. T.; Lunt, T.; Macian-Juan, R.; Rohde, V.; Sellmair, G.; Szepesi, T.; Wolfrum, E.; Zeidner, W.; Neu, R.

    2016-02-01

    Experiments have been performed at ASDEX Upgrade, aiming to investigate the impact of lithium in an all-metal-wall tokamak and attempting to enhance the pedestal operational space. For this purpose, a lithium pellet injector has been developed, capable of injecting pellets carrying a particle content ranging from 1.82 × 1019 atoms (0.21 mg) to 1.64 × 1020 atoms (1.89 mg). The maximum repetition rate is about 2 Hz. Free flight launch from the torus outboard side without a guiding tube was realized. In such a configuration, angular dispersion and speed scatter are low, and a transfer efficiency exceeding 90% was achieved in the test bed. Pellets are accelerated in a gas gun; hence special care was taken to avoid deleterious effects by the propellant gas pulse. Therefore, the main plasma gas species was applied as propellant gas, leading to speeds ranging from 420 m/s to 700 m/s. In order to minimize the residual amount of gas to be introduced into the plasma vessel, a large expansion volume equipped with a cryopump was added into the flight path. In view of the experiments, an optimal propellant gas pressure of 50 bars was chosen for operation, since at this pressure maximum efficiency and low propellant gas flux coincide. This led to pellet speeds of 585 m/s ± 32 m/s. Lithium injection has been achieved at ASDEX Upgrade, showing deep pellet penetration into the plasma, though pedestal broadening has not been observed yet.

  7. Experimental study of the radial structure of turbulence with a ultra-fast sweeping reflectometer in ASDEX upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Medvedeva, Anna [Max-Planck-Institut fuer Plasmaphysik, Boltzmannstrasse 2, D-85748 Garching (Germany); Commissariat a l' Energie Atomique et aux Energies Alternatives, 13108 Saint Paul Lez Durance (France); Universite de Lorraine, 34 cours Leopold, 54000 Nancy (France); Technische Universitat Munchen, James-Franck-Strasse1, D-85748 Garching (Germany); Bottereau, Christine; Clairet, Frederic; Molina, Diego [Universite de Lorraine, 34 cours Leopold, 54000 Nancy (France); Conway, Garrard [Max-Planck-Institut fuer Plasmaphysik, Boltzmannstrasse 2, D-85748 Garching (Germany); Heuraux, Stephane [Commissariat a l' Energie Atomique et aux Energies Alternatives, 13108 Saint Paul Lez Durance (France); Stroth, Ulrich [Max-Planck-Institut fuer Plasmaphysik, Boltzmannstrasse 2, D-85748 Garching (Germany); Technische Universitat Munchen, James-Franck-Strasse1, D-85748 Garching (Germany)

    2014-07-01

    Confinement of fusion plasmas is restricted by anomalous transport where micro-turbulence is suspected to play a major role. Experimental documentation of this turbulence, its dependence on the plasma temperature, density, current will provide insights in the nature of this turbulence and the driving parameters. In this work advantage is taken of the ultra-fast sweep capabilities of the V and W band (50-110 GHz) reflectometers, developed by CEA, to record fast plasma turbulent events on ASDEX upgrade. The X-mode polarization will provide a rather large radial access to the plasma from the very edge to, under certain conditions, the center. The scope of the work is to exploit the specific strengths of the diagnostic in order to study the radial spectra of fluctuations, radial turbulence spreading and the fast dynamic profile evolution after confinement transitions or changes in the discharge control parameters. First experimental data obtained during the ASDEX upgrade campaign 2014 are presented.

  8. Experimental study of the radial structure of turbulence with an ultra-fast swept reflectometer in ASDEX Upgrade

    International Nuclear Information System (INIS)

    Confinement of fusion plasmas is restricted by anomalous transport where micro-turbulence is suspected to play a major role. Experimental documentation of this turbulence, its dependence on the plasma temperature, density, current will provide insights in the nature of this turbulence and the driving parameters. In this work advantage is taken of the ultra-fast sweep capabilities of the V and W band (50-110 GHz) reflectometers, developed by CEA, to record fast plasma turbulent events on ASDEX Upgrade. The X-mode polarization provides a rather large radial access to the plasma from the very edge to, under certain conditions, the center. The scope of the work is to exploit the specific strengths of the diagnostic in order to study the radial spectra of fluctuations, radial turbulence spreading and the fast dynamic profile evolution after confinement transitions or changes in the discharge control parameters. The latest experimental data obtained during the ASDEX Upgrade campaign 2014 are presented.

  9. 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.

  10. Plasma geometry and current profile identification on ASDEX Upgrade using an integrated equilibrium generation and interpretation system

    International Nuclear Information System (INIS)

    The identification of ideal MHD equilibrium states at ASDEX Upgrade is the starting point for interpreting any diagnostic data dependent on knowledge of the flux surface geometry. The method of Function Parameterization (FP) starts with the Monte Carlo generation of a simulated equilibrium database, regression analysis of which yields simple functional representations of plasma geometry whose arguments are information-rich, uncorrelated linear combinations of simulated diagnostic signals. Once calculated, these FP expressions can be rapidly evaluated using experimental data. FP using magnetic data is in routine realtime use on ASDEX Upgrade for plasma position and shape control. An extension to FP using MSE data has recently been developed for realtime identification and control of the current profile on ASDEX Upgrade. Post-discharge interpretive equilibrium solutions are generated by the CLISTE code, which best fits a set of specified diagnostic data. CLISTE can include kinetic data and poloidal halo currents in the scrape-off layer as constraints on the equilibrium solution, a valuable feature which has been applied to ELM analysis. The code has recently been extended to interpret dB/dt data from magnetics and dγ/dt data from MSE to yield a best fit solution to the time derivative of the Grad-Shafranov equation -Δ*∂ψ/∂t = 2πμ0R ∂/∂t jφ. The ∂ψ/∂t solution is used to calculate the flux surface averaged profile which can be used to calculate current drive from auxiliary heating methods via the equation aux.heating = equil - σ - boot where boot is calculated from kinetic profiles and neoclassical theory and equil is an equilibrium output. This technique is being applied to analyse current profile modification by off-axis NBI on ASDEX Upgrade. (author)

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

    Science.gov (United States)

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

    2010-06-01

    The migration of carbon in low-density, low-confinement plasmas of ASDEX Upgrade was studied by injecting 13C 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 13C 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, 13C was deposited mainly on the high-field side tiles, while barely detectable amounts of 13C 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 13C experiments in ASDEX Upgrade. In the case of W-coated tiles, the 13C measurements were complemented by determining the total amount of deposited carbon (12C) on the tiles, which also shows strong deposition at the inner parts of the lower divertor. The estimated deposition of 13C on W at the divertor areas was less than 1.5% of the injected amount of 13C atoms. The 13C 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 13C 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.

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

    International Nuclear Information System (INIS)

    The migration of carbon in low-density, low-confinement plasmas of ASDEX Upgrade was studied by injecting 13C 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 13C 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, 13C was deposited mainly on the high-field side tiles, while barely detectable amounts of 13C 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 13C experiments in ASDEX Upgrade. In the case of W-coated tiles, the 13C measurements were complemented by determining the total amount of deposited carbon (12C) on the tiles, which also shows strong deposition at the inner parts of the lower divertor. The estimated deposition of 13C on W at the divertor areas was less than 1.5% of the injected amount of 13C atoms. The 13C 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 13C 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.

  13. Deformation measurement of internal components of ASDEX Upgrade using optical strain sensors

    Energy Technology Data Exchange (ETDEWEB)

    Vorpahl, C., E-mail: christian.vorpahl@ipp.mpg.de [Max Planck Institute for Plasma Physics, EURATOM Association, Boltzmannstr. 2, 85748 Garching (Germany); Suttrop, W.; Ebner, M.; Streibl, B.; Zohm, H. [Max Planck Institute for Plasma Physics, EURATOM Association, Boltzmannstr. 2, 85748 Garching (Germany)

    2013-10-15

    Highlights: ► A fibre-optic measurement for the deformation of in-vessel components has successfully been installed and commissioned at ASDEX Upgrade. ► This technology has thereby been qualified for in-vessel use at experimental nuclear fusion devices. ► The sensors were tested for their neutron tolerance and vacuum compatibility. ► Installation was done by copper–steel laser beam welding. ► The temporal and spatial resolutions of the system are sufficient to resolve oscillations due to internal coils and plasma disruptions. -- Abstract: A fibre-optic measurement system to analyse the deformation of in-vessel components has successfully been developed, installed and commissioned at ASDEX Upgrade (AUG). This technology has thereby been qualified for in-vessel use at experimental fusion devices. AUG is equipped with an internal conductor for passive plasma stabilisation called the Passive Stabilisation Loop (PSL), on which the recently installed 16 internal coils (B-coils) are directly mounted. The PSL structure is highly prone to vibrations, and the risk of resonant oscillations in response to B-coil induced forces necessitated the development of the present diagnostic. The diagnostic system consists of 34 fibre-optic strain sensors incorporated in two glass fibres. It is completely insensitive to electromagnetic disturbances. The fibres are customised to avoid inconvenient excess fibre length in the vacuum vessel. They were tested for their neutron tolerance and vacuum compatibility prior to installation. The actual sensors are embedded in stainless steel carriers that were attached to the PSL, which is made of copper, by laser welding. Appropriate welding parameters were determined in view of the metallurgical dissimilarity. The weld quality was approved by tensile tests and microscopic investigations. Accurate in-vessel positioning of the sensors was assured using a 3D measurement system and coordinates from CAD. The data acquisition allows a

  14. Machine safety issues with respect to the extension of ECRH systems at ASDEX Upgrade

    Directory of Open Access Journals (Sweden)

    Schuberta Martin

    2015-01-01

    Full Text Available The beam intensity of electron cyclotron resonance heating at ASDEX Upgrade has the potential to seriously damage in-vessel components, whenever not fully absorbed by the plasma. Operation is, therefore, interlocked with both plasma current and density above a given threshold. Microwave protection detectors installed in several ports on the low field side switch the heating system off, in case the stray radiation exceeds a given threshold. During regular inspections, however, damages were reported in the vicinity of the launchers and in particular around the tiles of the heat shield. On one hand, it was found that insulating material, which may not face the plasma, degraded due to millimetre wave absorption. The waves entered the free space behind the heat shield through gaps. On the other hand, local damage even of metallic components was observed on surfaces, which were directly exposed to the microwave beam. Polarisation errors, which led to a local shine through of significant beam power, were responsible. We note that this happened mainly on the high field side in a certain distance to the microwave protection detectors, which were not triggered by the events. In order to increase the level of protection, we identify three necessary measures: Firstly, polarisation control is to be automated such, that mode content and shine through can be monitored. Secondly, by installing additional detectors, the spatial coverage of stray radiation monitoring is enlarged. Thirdly, the heat shield tiles will be redesigned in order to increase the shielding against millimetre waves.

  15. Investigation of scrape-off layer and divertor heat transport in ASDEX Upgrade L-mode

    Science.gov (United States)

    Sieglin, B.; Eich, T.; Faitsch, M.; Herrmann, A.; Scarabosio, A.; the ASDEX Upgrade Team

    2016-05-01

    Power exhaust is one of the major challenges for the development of a fusion power plant. Predictions based upon a multimachine database give a scrape-off layer power fall-off length {λq}≤slant 1 mm for large fusion devices such as ITER. The power deposition profile on the target is broadened in the divertor by heat transport perpendicular to the magnetic field lines. This profile broadening is described by the power spreading S. Hence both {λq} and S need to be understood in order to estimate the expected divertor heat load for future fusion devices. For the investigation of S and {λq} L-Mode discharges with stable divertor conditions in hydrogen and deuterium were conducted in ASDEX Upgrade. A strong dependence of S on the divertor electron temperature and density is found which is the result of the competition between parallel electron heat conductivity and perpendicular diffusion in the divertor region. For high divertor temperatures it is found that the ion gyro radius at the divertor target needs to be considered. The dependence of the in/out asymmetry of the divertor power load on the electron density is investigated. The influence of the main ion species on the asymmetric behaviour is shown for hydrogen, deuterium and helium. A possible explanation for the observed asymmetry behaviour based on vertical drifts is proposed.

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

    International Nuclear Information System (INIS)

    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

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

    International Nuclear Information System (INIS)

    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 thermo diffusive 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. (author)

  18. Effect of radial electric field and ripple on edge neutral beam ion distribution in ASDEX Upgrade

    Science.gov (United States)

    Hynönen, V.; Kurki-Suonio, T.; Suttrop, W.; Stäbler, A.; ASDEX Upgrade Team

    2008-03-01

    The neutral beam injected fast ion distribution at the ASDEX Upgrade edge region is studied focusing on the difference between co- and counter-injected neutral beams. The slowing-down distribution of beam ions is simulated using the orbit-following Monte Carlo code ASCOT. The edge fast ion density and its gradient are higher for counter-injection than for co-injection. Also the distribution in the velocity space is different: for co-injection, there exists a population of untrapped particles which for counter-injection is found only when the effect of a non-constant, experimentally obtained quiescent H-mode radial electric field is included in the simulation. Toroidal ripple removes ions having small particle pitch, thereby reducing the density and density gradient, whereas the radial electric field has the opposite effect. Including simultaneously the effects of both ripple and the radial electric field restores the distribution close to the ideal case where both of them are neglected. The radial electric field is found to squeeze the orbit of a counter-injected neutral beam ion but to widen the orbit of a co-injected ion, and to cause transitions in the orbit topologies which are reflected in the fast ion distribution.

  19. Deuterium depth profile quantification in a ASDEX Upgrade divertor tile using secondary ion mass spectrometry

    Science.gov (United States)

    Ghezzi, F.; Caniello, R.; Giubertoni, D.; Bersani, M.; Hakola, A.; Mayer, M.; Rohde, V.; Anderle, M.

    2014-10-01

    We present the results of a study where secondary ion mass spectrometry (SIMS) has been used to obtain depth profiles of deuterium concentration on plasma facing components of the first wall of the ASDEX Upgrade tokamak. The method uses primary and secondary standards to quantify the amount of deuterium retained. Samples of bulk graphite coated with tungsten or tantalum-doped tungsten are independently profiled with three different SIMS instruments. Their deuterium concentration profiles are compared showing good agreement. In order to assess the validity of the method, the integrated deuterium concentrations in the coatings given by one of the SIMS devices is compared with nuclear reaction analysis (NRA) data. Although in the case of tungsten the agreement between NRA and SIMS is satisfactory, for tantalum-doped tungsten samples the discrepancy is significant because of matrix effect induced by tantalum and differently eroded surface (W + Ta always exposed to plasma, W largely shadowed). A further comparison where the SIMS deuterium concentration is obtained by calibrating the measurements against NRA values is also presented. For the tungsten samples, where no Ta induced matrix effects are present, the two methods are almost equivalent.The results presented show the potential of the method provided that the standards used for the calibration reproduce faithfully the matrix nature of the samples.

  20. Overview on plasma operation with a full tungsten wall in ASDEX Upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Neu, R., E-mail: Rudolf.Neu@ipp.mpg.de [Max-Planck-Institut für Plasmaphysik, EURATOM-Association, D-85748 Garching (Germany); Kallenbach, A.; Balden, M.; Bobkov, V. [Max-Planck-Institut für Plasmaphysik, EURATOM-Association, D-85748 Garching (Germany); Coenen, J.W. [Institut für Energie- und Klimaforschung IV, Forschungszentrum Jülich, TEC, Association EURATOM-FZJ, D-52425 Jülich (Germany); Drube, R.; Dux, R.; Greuner, H.; Herrmann, A.; Hobirk, J. [Max-Planck-Institut für Plasmaphysik, EURATOM-Association, D-85748 Garching (Germany); Höhnle, H. [Institut für Plasmaforschung, Universität Stuttgart, Stuttgart (Germany); Krieger, K.; Kočan, M.; Lang, P.; Lunt, T.; Maier, H.; Mayer, M.; Müller, H.W.; Potzel, S.; Pütterich, T. [Max-Planck-Institut für Plasmaphysik, EURATOM-Association, D-85748 Garching (Germany); and others

    2013-07-15

    Operation with all tungsten plasma facing components has become routine in ASDEX Upgrade. The conditioning of the device is strongly simplified and short glow discharges are used only on a daily basis. The long term fuel retention was reduced by more than a factor of 5 as demonstrated in gas balance as well as in post mortem analyses. Injecting nitrogen for radiative cooling, discharges with additional heating power up to 23 MW have been achieved, providing good confinement (H98{sub y2} = 1), divertor power loads around 5 MW m{sup −2} and divertor temperatures below 10 eV. ELM mitigation by pellet ELM pacemaking or magnetic perturbation coils reduces the deposited energy during ELMs, but also keeps the W density at the pedestal low. As a recipe to keep the central W concentration sufficiently low, central (wave) heating is well established and low density H-Modes could be re-established with the newly available ECRH power of up to 4 MW. The ICRH induced W sources could be strongly reduced by applying boron coatings to the poloidal guard limiters.

  1. Adjoint Monte Carlo Simulation of Fusion Product Activation Probe Experiment in ASDEX Upgrade tokamak

    CERN Document Server

    Äkäslompolo, Simppa; Tardini, Giovanni; Kurki-Suonio, Taina

    2015-01-01

    The activation probe is a robust tool to measure flux of fusion products from a magnetically confined plasma. A carefully chosen solid sample is exposed to the flux, and the impinging ions transmute the material makig it radioactive. Ultra-low level gamma-ray spectroscopy is used post mortem to measure the activity and, thus, the number of fusion products. This contribution presents the numerical analysis of the first measurement in the ASDEX Upgrade tokamak, which was also the first experiment to measure a single discharge. The ASCOT suite of codes was used to perform adjoint/reverse Monte-Carlo calculations of the fusion products. The analysis facilitated, for the first time, a comparison of numerical and experimental values for absolutely calibrated flux. The results agree to within 40%, which can be considered remarkable considering the fact that all features of the plasma cannot be accounted in the simulations. Also an alternative probe orientation was studied. The results suggest that a better optimized...

  2. 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.

  3. Non-monotonic growth rates of sawtooth precursors evidenced with a new method on ASDEX Upgrade

    Science.gov (United States)

    Vezinet, D.; Igochine, V.; Weiland, M.; Yu, Q.; Gude, A.; Meshcheriakov, D.; Sertoli, M.; the Asdex Upgrade Team; the EUROfusion MST1 Team

    2016-08-01

    This paper describes a new method to derive, from soft x-ray (SXR) tomography, robust estimates of the core displacement, growth rate and frequency of a 1/1 sawtooth crash precursor. The method is valid for very peaked SXR profiles and is robust against both the inversion algorithm and the presence of tungsten in a rotating plasma. Three typical ASDEX Upgrade crashes are then analysed. In all cases a postcursor is observed, suggesting incomplete reconnection. Despite different dynamics, in all three cases the growth rate of the core displacement shows similar features. First, it is not constant, supporting the idea of non-linear growth. Second, it can be divided into clearly identified phases with quasi-constant growth rates, suggesting sudden change of growth regime rather than smooth transitions. Third, its evolution is non-monotonic, with phases of accelerated growth followed by damped phases. This damping is interpreted for two cases respectively as an effect of fast ions and of mode coupling, based on the result of a MHD simulation. The mode frequency is observed in all cases to be closely related to the plasma bulk rotation profile, with little or no visible effect of the electron diamagnetic drift frequency. The onset criterion could not be clearly identified and it is shown that the role of the pressure gradient is not as expected from a naive extrapolation of the linear stability theory.

  4. 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.

  5. Critical issues identified by the ASDEX Upgrade edge and divertor modelling

    International Nuclear Information System (INIS)

    A detailed comparison between the ASDEX Upgrade (AUG) experimental data and results of the SOLPS 2D edge code simulations has recently been performed. High quality upstream profiles of electron density and ion and electron temperatures in the scrape-off layer (SOL) of AUG have been collected for two shots with different upstream collisionalities: a low density ELMy H-mode shot (low collisionality) and a medium density Ohmic shot (higher collisionality). A generally broad agreement, within a factor 2, considering basic parameters characterising the divertor, has been reached between simulations and experiment. In both Ohmic and H-mode shots, however, the tendency of SOLPS solutions to underestimate the divertor electron temperature and overestimate its density has been reliably established. Two main possible causes of the discrepancies have been considered: some deficiencies in the neutral modelling (e.g. missing atomic and molecular reactions in EIRENE, the Monte-Carlo neutral part of SOLPS), and the presence of a significant population of supra-thermal ions and electrons in the SOL and divertor plasma. The results of dedicated SOLPS runs where the sensitivity of the code solution to various assumptions of the neutral model and parallel heat transport of ions and electrons are described. A comparison between simulated and experimentally measured Mach numbers of the parallel ion flow in the SOL is presented, and conditions necessary for obtaining fast flows in the code are analysed. (author)

  6. Gyrokinetic studies of core turbulence features in ASDEX Upgrade: Can gyrokinetic simulations match the fluctuation measurements?

    Science.gov (United States)

    Banon Navarro, Alejandro

    2015-11-01

    Worldwide, gyrokinetic codes are used to predict the dominant micro-instabilities as well as the resulting anomalous transport in fusion experiments. A careful verification and validation of these codes is crucial to develop confidence in the model and improving the predictive capabilities of the numerical simulations. To date, the validation of gyrokinetic simulations versus experiments is mainly done at a macroscopic level, namely, by comparing turbulent heat fluxes. This is usually achieved by varying the profile gradients within the experimental error bars until a match with the experimental heat fluxes is obtained. However, since the turbulent fluxes are caused by plasma fluctuations on microscopic scales, it is also necessary to validate gyrokinetic codes on a microscopic level. We will describe a recent step in this direction by presenting simulation results with the gyrokinetic code GENE for an ASDEX Upgrade discharge. In particular, after flux-matched simulations are achieved, density fluctuations measured by means of Doppler reflectometry are compared with results of gyrokinetic simulations. We will also show that density and temperature fluctuation amplitudes and even the fluctuation spectra can be very sensitive to small changes in the profile gradients. This implies that a match of gyrokinetic simulations with experiment measurements for these quantities can be very difficult to achieve. However, it is observed that cross-phases between different quantities are robust to changes in this parameter, indicating that cross-phases could be a better observable for comparisons with experimental measurements.

  7. Overview of ASDEX Upgrade results—development of integrated operating scenarios for ITER

    Science.gov (United States)

    Günter, S.; Angioni, C.; Apostoliceanu, M.; Atanasiu, C.; Balden, M.; Becker, G.; Becker, W.; Behler, K.; Behringer, K.; Bergmann, A.; Bilato, R.; Bizyukov, I.; Bobkov, V.; Bolzonella, T.; Borba, D.; Borrass, K.; Brambilla, M.; Braun, F.; Buhler, A.; Carlson, A.; Chankin, A.; Chen, J.; Chen, Y.; Cirant, S.; Conway, G.; Coster, D.; Dannert, T.; Dimova, K.; Drube, R.; Dux, R.; Eich, T.; Engelhardt, K.; Fahrbach, H.-U.; Fantz, U.; Fattorini, L.; Foley, M.; Franzen, P.; Fuchs, J. C.; Gafert, J.; Gal, K.; Gantenbein, G.; García Muñoz, M.; Gehre, O.; Geier, A.; Giannone, L.; Gruber, O.; Haas, G.; Hartmann, D.; Heger, B.; Heinemann, B.; Herrmann, A.; Hobirk, J.; Hohenöcker, H.; Horton, L.; Huart, M.; Igochine, V.; Jacchia, A.; Jakobi, M.; Jenko, F.; Kallenbach, A.; Kálvin, S.; Kardaun, O.; Kaufmann, M.; Keller, A.; Kendl, A.; Kick, M.; Kim, J.-W.; Kirov, K.; Klose, S.; Kochergov, R.; Kocsis, G.; Kollotzek, H.; Konz, C.; Kraus, W.; Krieger, K.; Kurki-Suonio, T.; Kurzan, B.; Lackner, K.; Lang, P. T.; Lauber, P.; Laux, M.; Leuterer, F.; Likonen, J.; Lohs, A.; Lorenz, A.; Lorenzini, R.; Lyssoivan, A.; Maggi, C.; Maier, H.; Mank, K.; Manini, A.; Manso, M.-E.; Mantica, P.; Maraschek, M.; Martin, P.; Mast, K. F.; Mayer, M.; McCarthy, P.; Meyer, H.; Meisel, D.; Meister, H.; Menmuir, S.; Meo, F.; Merkel, P.; Merkel, R.; Merkl, D.; Mertens, V.; Monaco, F.; Mück, A.; Müller, H. W.; Münich, M.; Murmann, H.; Na, Y.-S.; Narayanan, R.; Neu, G.; Neu, R.; Neuhauser, J.; Nishijima, D.; Nishimura, Y.; Noterdaeme, J.-M.; Nunes, I.; Pacco-Düchs, M.; Pautasso, G.; Peeters, A. G.; Pereverzev, G.; Pinches, S.; Poli, E.; Posthumus-Wolfrum, E.; Pütterich, T.; Pugno, R.; Quigley, E.; Radivojevic, I.; Raupp, G.; Reich, M.; Riedl, R.; Ribeiro, T.; Rohde, V.; Roth, J.; Ryter, F.; Saarelma, S.; Sandmann, W.; Santos, J.; Schall, G.; Schilling, H.-B.; Schirmer, J.; Schneider, W.; Schramm, G.; Schweinzer, J.; Schweizer, S.; Scott, B.; Seidel, U.; Serra, F.; Sihler, C.; Silva, A.; Sips, A.; Speth, E.; Stäbler, A.; Steuer, K.-H.; Stober, J.; Streibl, B.; Strintzi, D.; Strumberger, E.; Suttrop, W.; Tardini, G.; Tichmann, C.; Treutterer, W.; Troppmann, M.; Tsalas, M.; Urano, H.; Varela, P.; Wagner, D.; Wesner, F.; Würsching, E.; Ye, M. Y.; Yoon, S.-W.; Yu, Q.; Zaniol, B.; Zasche, D.; Zehetbauer, T.; Zehrfeld, H.-P.; Zilker, M.; Zohm, H.

    2005-10-01

    Significant progress has been made on ASDEX Upgrade during the last two years in the basic understanding of transport, in the extension of the improved H-mode in parameter space and towards an integrated operating scenario and in the development of control methods for major performance limiting instabilities. The important features were the understanding of particle transport and the control of impurity accumulation based on it, the satisfactory operation with predominantly tungsten-clad walls, the improved H-mode operation over density ranges and for temperature ratios covering (non-simultaneously) the ITER requirements on ν*, n/nGW and Te/Ti, the ELM frequency control by pellet injection and the optimization of NTM suppression by DC-ECCD through variation of the launching angle. From these experiments an integrated scenario has emerged which extrapolates to a 50% improvement in n T τ or a 30% reduction of the required current when compared with the ITER base-line assumptions, with moderately peaked electron and controllable high-Z density profiles.

  8. Ten years of W programme in ASDEX Upgrade-challenges and conclusions

    International Nuclear Information System (INIS)

    Since 1999 ASDEX Upgrade increased its tungsten plasma-facing components (PFCs) and finally reached a full W coverage in 2007. Most of the initial goals of the investigations were successfully achieved. A highlight of the investigations was multiple start-ups and operation without any boronization demonstrating that performance and confinement similar to boronized operation with carbon PFCs can be reached in high power, high density discharges. This also allowed the investigation of the hydrogen retention without disturbing effects from the low-Z coating. A strong reduction of hydrogen retention was found in gas balance measurements as well as in post-mortem analyses. On the other hand, an almost complete suppression of low-Z divertor radiation was achieved after boronization, providing valuable information on the control requirements of radiative cooling by artificially introduced impurities. Among the challenges remains the strong increase of the W source and W concentration resulting from ICRH. At the same time it helped to identify the underlying physics and may lead to solutions superior to the presently used ones.

  9. Development of tungsten coated first wall and high heat flux components for application in ASDEX Upgrade

    International Nuclear Information System (INIS)

    In the tokamak experiment ASDEX Upgrade, the investigation of tungsten as a first wall material is an ongoing research project. In a step-by-step strategy, the tungsten covered surface area is increased from campaign to campaign. For this purpose an industrial-scale method for coating graphite with micrometer tungsten films had to be identified. Test coatings deposited by magnetron sputtering and by plasma-arc deposition were compared. By X-ray analysis it was found that sputter-deposited coatings suffer from high compressive stress (1.7 GPa). This leads to delamination when a film thickness of about 3 μm is exceeded. For arc-deposited coatings, a compressive stress value of 0.5 GPa was determined and no delamination occurred up to the maximum film thicknesses investigated, i.e. 10 μm. Upon thermal loading, none of the arc-deposited coatings failed up to the melting condition, while one sputter-coating delaminated. First results on similar investigations employing CFC substrates are presented

  10. Improved Collective Thomson Scattering measurements of fast ions at ASDEX Upgrade

    CERN Document Server

    Rasmussen, J; Stejner, M; Salewski, M; Jacobsen, A S; Korsholm, S B; Leipold, F; Meo, F; Michelsen, P K; Moseev, D; Schubert, M; Stober, J; Tardini, G; Wagner, D

    2013-01-01

    Understanding the behaviour of the confined fast ions is important in both current and future fusion experiments. These ions play a key role in heating the plasma and will be crucial for achieving conditions for burning plasma in next-step fusion devices. Microwave-based Collective Thomson Scattering (CTS) is well suited for reactor conditions and offers such an opportunity by providing measurements of the confined fast-ion distribution function resolved in space, time and 1D velocity space. We currently operate a CTS system at ASDEX Upgrade using a gyrotron which generates probing radiation at 105 GHz. A new setup using two independent receiver systems has enabled improved subtraction of the background signal, and hence the first accurate characterization of fast-ion properties. Here we review this new dual-receiver CTS setup and present results on fast-ion measurements based on the improved background characterization. These results have been obtained both with and without NBI heating, and with the measurem...

  11. Estimation of sheath potentials in front of ASDEX upgrade ICRF antenna with SSWICH asymptotic code

    Energy Technology Data Exchange (ETDEWEB)

    Křivská, A., E-mail: alena.krivska@rma.ac.be [LPP-ERM/KMS, Royal Military Academy, 30 Avenue de la Renaissance B-1000, Brussels (Belgium); Bobkov, V.; Jacquot, J.; Ochoukov, R. [Max-Planck-Institut für Plasmaphysik, D-85748 Garching (Germany); Colas, L. [CEA, IRFM, F-13108 Saint-Paul-Lez-Durance (France); Milanesio, D. [Politecnico di Torino, Corso Duca degli Abruzzi 24, I-10129 Torino (Italy)

    2015-12-10

    Multi-megawatt Ion Cyclotron Range of Frequencies (ICRF) heating became problematic in ASDEX Upgrade (AUG) tokamak after coating of ICRF antenna limiters and other plasma facing components by tungsten. Strong impurity influx was indeed produced at levels of injected power markedly lower than in the previous experiments. It is assumed that the impurity production is mainly driven by parallel component of Radio-Frequency (RF) antenna electric near-field E// that is rectified in sheaths. In this contribution we estimate poloidal distribution of sheath Direct Current (DC) potential in front of the ICRF antenna and simulate its relative variations over the parametric scans performed during experiments, trying to reproduce some of the experimental observations. In addition, relative comparison between two types of AUG ICRF antenna configurations, used for experiments in 2014, has been performed. For this purpose we use the Torino Polytechnic Ion Cyclotron Antenna (TOPICA) code and asymptotic version of the Self-consistent Sheaths and Waves for Ion Cyclotron Heating (SSWICH) code. Further, we investigate correlation between amplitudes of the calculated oscillating sheath voltages and the E// fields computed at the lateral side of the antenna box, in relation with a heuristic antenna design strategy at IPP Garching to mitigate RF sheaths.

  12. 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.

  13. Shear strength of the ASDEX Upgrade TF coil insulation: rupture, fatigue and creep behaviour

    International Nuclear Information System (INIS)

    The interlaminar shear strength of the insulation system for the 16 toroidal field (TF) coils of ASDEX Upgrade is investigated. The interlaminar shear properties of the glass-epoxy insulation are primarily determined by the resin system 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-epoxy 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. Finally, a visco-elastic model was set up to describe the creep behaviour of the insulation system. (author)

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

    International Nuclear Information System (INIS)

    This paper 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 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-epoxy 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 = 60C, as also was the temperature dependence of the creep rate (40 C, 60C, 80 C). The results obtained are not based on safe statistics. Nevertheless, they show clear trends. Finally, a visco-elastic model was set up to describe the creep behavior of the insulation system

  15. Improved time-frequency analysis of ASDEX Upgrade reflectometry data using the reassigned spectrogram technique

    International Nuclear Information System (INIS)

    The spectrogram is one of the best-known time-frequency distributions suitable to analyze signals whose energy varies both in time and frequency. In reflectometry, it has been used to obtain the frequency content of FM-CW signals for density profile inversion and also to study plasma density fluctuations from swept and fixed frequency data. Being implemented via the short-time Fourier transform, the spectrogram is limited in resolution, and for that reason several methods have been developed to overcome this problem. Among those, we focus on the reassigned spectrogram technique that is both easily automated and computationally efficient requiring only the calculation of two additional spectrograms. In each time-frequency window, the technique reallocates the spectrogram coordinates to the region that most contributes to the signal energy. The application to ASDEX Upgrade reflectometry data results in better energy concentration and improved localization of the spectral content of the reflected signals. When combined with the automatic (data driven) window length spectrogram, this technique provides improved profile accuracy, in particular, in regions where frequency content varies most rapidly such as the edge pedestal shoulder.

  16. Real-time diagnostic integration with the ASDEX upgrade control system

    International Nuclear Information System (INIS)

    Operating in advanced plasma scenarios has become one of the major goals on the way towards ITER and a future fusion reactor. This implies the reinforced control of physics quantities like pressure profiles or magnetic island structures, which have to be reconstructed in real-time for this purpose. To achieve this goal the collaboration scheme between diagnostic data processing and real-time control has to be fundamentally changed from strict separation to open bidirectional information exchange in real-time. ASDEX Upgrade is currently designing and building a distributed computer cluster to implement such an integrated diagnostic and control system. The main topics comprise modular framework design, low-latency data communication via networks, and built-in synchronisation methods. We show how the discharge control system's modular framework is extended to publish calculated quantities via the network transparent to algorithm designers. A communication layer allows the exchange of real-time information between computation nodes with automatised routing even over several networks. Finally, in order to consistently combine data from independent sources, synchronisation methods are developed. Thus, sophisticated feedback control with time scales of milliseconds become feasible.

  17. Improvement of the divertor bolometer diagnostic in the ASDEX Upgrade tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Sehmer, Till; Meister, Hans; Bernert, Matthias; Koll, Juergen; Reimold, Felix; Wischmeier, Marco; Fantz, Ursel [Max-Planck-Institut fuer Plasmaphysik, Boltzmannstr. 2, 85748 Garching (Germany); Collaboration: ASDEX Upgrade Team

    2015-05-01

    For future fusion devices such as ITER, the radiation balance in the divertor region will have a significant impact on the power exhaust balance. Therefore, scenarios with strongly localized radiation, like radiation in the high field side high density (HFSHD) region, X-Point radiation or radiation in the divertor legs during detachment, will be investigated in the next ASDEX Upgrade (AUG) operation campaign 2015. To obtain accurately the absolute divertor radiation out of these measurements, the AUG foil bolometer diagnostic system in the divertor region has been enhanced; two new cameras have been designed and manufactured. One will be mounted below the roof baffle and contains 28 lines of sight (LOS), which will observe the mentioned regions of particular physical interest. The second camera consists of 4 LOS and will be mounted at the high field side above the inner divertor nose. It will observe radiation arising from the X-Point region and from the outer divertor. The data will be analysed with a tomographic reconstruction algorithm to localize and quantify the divertor radiation.

  18. Adjoint Monte Carlo simulation of fusion product activation probe experiment in ASDEX Upgrade tokamak

    International Nuclear Information System (INIS)

    The activation probe is a robust tool to measure flux of fusion products from a magnetically confined plasma. A carefully chosen solid sample is exposed to the flux, and the impinging ions transmute the material making it radioactive. Ultra-low level gamma-ray spectroscopy is used post mortem to measure the activity and, thus, the number of fusion products. This contribution presents the numerical analysis of the first measurement in the ASDEX Upgrade tokamak, which was also the first experiment to measure a single discharge. The ASCOT suite of codes was used to perform adjoint/reverse Monte Carlo calculations of the fusion products. The analysis facilitates, for the first time, a comparison of numerical and experimental values for absolutely calibrated flux. The results agree to within a factor of about two, which can be considered a quite good result considering the fact that all features of the plasma cannot be accounted in the simulations.Also an alternative to the present probe orientation was studied. The results suggest that a better optimized orientation could measure the flux from a significantly larger part of the plasma. A shorter version of this contribution is due to be published in PoS at: 1st EPS conference on Plasma Diagnostics

  19. Fast ion temperature measurements using ball-pen probes in the SOL of ASDEX Upgrade during L-mode

    Czech Academy of Sciences Publication Activity Database

    Adámek, Jiří; Horáček, Jan; Müller, H. W.; Schrittwieser, R.; Tichý, M.; Nielsen, A.H.

    Mulhouse : European Physical Society, 2011 - (Becoulet, A.; Hoang, T.; Stroth, U.), P1.059-P1.059 ISBN 2-914771-68-1. - (EPS. 35G). [European Physical Society Conference on Plasma Physics /38th./. Strasbourg (FR), 27.06.2011-01.07.2011] R&D Projects: GA AV ČR KJB100430901; GA MŠk 7G09042 Institutional research plan: CEZ:AV0Z20430508 Keywords : ASDEX Upgrade * ball-pen probes * L-mode * SOL * tokamak Subject RIV: BL - Plasma and Gas Discharge Physics http://ocs.ciemat.es/EPS2011PAP/pdf/P1.059.pdf

  20. Pellet refuelling of particle loss due to ELM mitigation with RMPs in the ASDEX Upgrade tokamak at low collisionality

    CERN Document Server

    Valovič, M; Kirk, A; Suttrop, W; Cavedon, M; Fischer, L R; Garzotti, L; Guimarais, L; Kocsis, G; Cseh, G; Plőckl, B; Szepesi, T; Thornton, A; Mlynek, A; Tardini, G; Viezzer, E; Scannell, R; Wolfrum, E

    2015-01-01

    The complete refuelling of the plasma density loss (pump-out) caused by mitigation of Edge Localised Modes (ELMs) is demonstrated on the ASDEX Upgrade tokamak. The plasma is refuelled by injection of frozen deuterium pellets and ELMs are mitigated by external resonant magnetic perturbations (RMPs). In this experiment relevant dimensionless parameters, such as relative pellet size, relative RMP amplitude and pedestal collisionality are kept at the ITER like values. Refuelling of density pump out requires a factor of two increase of nominal fuelling rate. Energy confinement and pedestal temperatures are not restored to pre-RMP values by pellet refuelling.

  1. Pellet refuelling of particle loss due to ELM mitigation with RMPs in the ASDEX Upgrade tokamak at low collisionality

    Science.gov (United States)

    Valovič, M.; Lang, P. T.; Kirk, A.; Suttrop, W.; Cavedon, M.; Cseh, G.; Dunne, M.; Fischer, L. R.; Garzotti, L.; Guimarais, L.; Kocsis, G.; Mlynek, A.; Plőckl, B.; Scannell, R.; Szepesi, T.; Tardini, G.; Thornton, A.; Viezzer, E.; Wolfrum, E.; the ASDEX Upgrade Team; the EUROfusion MST1 Team

    2016-06-01

    The complete refuelling of the plasma density loss (pump-out) caused by mitigation of edge localised modes (ELMs) is demonstrated on the ASDEX Upgrade tokamak. The plasma is refuelled by injection of frozen deuterium pellets and ELMs are mitigated by external resonant magnetic perturbations (RMPs). In this experiment relevant dimensionless parameters, such as relative pellet size, relative RMP amplitude and pedestal collisionality are kept at the ITER like values. Refuelling of density pump out of the size of Δ n/n∼ 30% requires a factor of two increase of nominal fuelling rate. Energy confinement and pedestal temperatures are not restored to pre-RMP values by pellet refuelling.

  2. Deuterium depth profile quantification in a ASDEX Upgrade divertor tile using secondary ion mass spectrometry

    International Nuclear Information System (INIS)

    Highlights: • We measured absolute local concentration of D in W samples by three Secondary Ions Mass Spectrometry (SIMS) apparatus. • Implanted primary standard and special secondary standards were prepared to calibrate the measurements. • D concentrations integrated along the depth were compared with absolute NRA measurements. - Abstract: We present the results of a study where secondary ion mass spectrometry (SIMS) has been used to obtain depth profiles of deuterium concentration on plasma facing components of the first wall of the ASDEX Upgrade tokamak. The method uses primary and secondary standards to quantify the amount of deuterium retained. Samples of bulk graphite coated with tungsten or tantalum-doped tungsten are independently profiled with three different SIMS instruments. Their deuterium concentration profiles are compared showing good agreement. In order to assess the validity of the method, the integrated deuterium concentrations in the coatings given by one of the SIMS devices is compared with nuclear reaction analysis (NRA) data. Although in the case of tungsten the agreement between NRA and SIMS is satisfactory, for tantalum-doped tungsten samples the discrepancy is significant because of matrix effect induced by tantalum and differently eroded surface (W + Ta always exposed to plasma, W largely shadowed). A further comparison where the SIMS deuterium concentration is obtained by calibrating the measurements against NRA values is also presented. For the tungsten samples, where no Ta induced matrix effects are present, the two methods are almost equivalent.The results presented show the potential of the method provided that the standards used for the calibration reproduce faithfully the matrix nature of the samples

  3. Influence of gas injection location and magnetic perturbations on ICRF antenna performance in ASDEX Upgrade

    International Nuclear Information System (INIS)

    In ASDEX Upgrade H-modes with H98≈0.95, similar effect of the ICRF antenna loading improvement by local gas injection was observed as previously in L-modes. The antenna loading resistance Ra between and during ELMs can increase by more than 25% after a switch-over from a deuterium rate of 7.5⋅1021 D/s injected from a toroidally remote location to the same amount of deuterium injected close to an antenna. However, in contrast to L-mode, this effect is small in H-mode when the valve downstream w.r.t. parallel plasma flows is used. In L-mode, a non-linearity of Ra at PICRPa>30% with no effect of spectrum and phase of MPs on Ra found so far. In the case ELMs are fully mitigated, the antenna loading is higher and steadier. In the case ELMs are not fully mitigated, the value of Ra between ELMs is increased. Looking at the W source modification for the improved loading, the local gas injection is accompanied by decreased values of tungsten (W) influx ΓW from the limiters and its effective sputtering yield Yw, with the exception of the locations directly at the antenna gas valve. Application of MPs leads to increase of ΓW and Yw for some of the MP phases. With nitrogen seeding in the divertor, ICRF is routinely used to avoid impurity accumulation and that despite enhanced ΓW and YW at the antenna limiters

  4. H-mode pedestal scaling in DIII-D, ASDEX Upgrade, and JET

    International Nuclear Information System (INIS)

    Multidevice pedestal scaling experiments in the DIII-D, ASDEX Upgrade (AUG), and JET tokamaks are presented in order to test two plasma physics pedestal width models. The first model proposes a scaling of the pedestal width Δ/a ∝ ρ*1/2 to ρ* based on the radial extent of the pedestal being set by the point where the linear turbulence growth rate exceeds the ExB velocity. In the multidevice experiment where ρ* at the pedestal top was varied by a factor of four while other dimensionless parameters where kept fixed, it has been observed that the temperature pedestal width in real space coordinates scales with machine size, and that therefore the gyroradius scaling suggested by the model is not supported by the experiments. The density pedestal width is not invariant with ρ* which after comparison with a simple neutral fuelling model may be attributed to variations in the neutral fuelling patterns. The second model, EPED1, is based on kinetic ballooning modes setting the limit of the radial extent of the pedestal region and leads to Δψ ∝ βp1/2. All three devices show a scaling of the pedestal width in normalised poloidal flux as Δψ ∝ βp1/2, as described by the kinetic ballooning model; however, on JET and AUG, this could not be distinguished from an interpretation where the pedestal is fixed in real space. Pedestal data from all three devices have been compared with the predictive pedestal model EPED1 and the model produces pedestal height values that match the experimental data well.

  5. Deuterium depth profile quantification in a ASDEX Upgrade divertor tile using secondary ion mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Ghezzi, F., E-mail: ghezzi@ifp.cnr.it [Istituto di Fisica del Plasma “Piero Caldirola” IFP Euratom-ENEA-CNR Association, Via R. Cozzi 53, 20125 Milan (Italy); Caniello, R. [Istituto di Fisica del Plasma “Piero Caldirola” IFP Euratom-ENEA-CNR Association, Via R. Cozzi 53, 20125 Milan (Italy); Giubertoni, D.; Bersani, M. [FBK, Via Sommarive 18, 38123 Povo, TN (Italy); Hakola, A. [VTT, Association Euratom-Tekes, P.O. Box 1000, 02044 VTT (Finland); Mayer, M.; Rohde, V. [Max-Planck-Institut für Plasmaphysik, 85748 Garching (Germany); Anderle, M. [Knowledge Department, Autonomous Province of Trento, 38123 Trento (Italy)

    2014-10-01

    Highlights: • We measured absolute local concentration of D in W samples by three Secondary Ions Mass Spectrometry (SIMS) apparatus. • Implanted primary standard and special secondary standards were prepared to calibrate the measurements. • D concentrations integrated along the depth were compared with absolute NRA measurements. - Abstract: We present the results of a study where secondary ion mass spectrometry (SIMS) has been used to obtain depth profiles of deuterium concentration on plasma facing components of the first wall of the ASDEX Upgrade tokamak. The method uses primary and secondary standards to quantify the amount of deuterium retained. Samples of bulk graphite coated with tungsten or tantalum-doped tungsten are independently profiled with three different SIMS instruments. Their deuterium concentration profiles are compared showing good agreement. In order to assess the validity of the method, the integrated deuterium concentrations in the coatings given by one of the SIMS devices is compared with nuclear reaction analysis (NRA) data. Although in the case of tungsten the agreement between NRA and SIMS is satisfactory, for tantalum-doped tungsten samples the discrepancy is significant because of matrix effect induced by tantalum and differently eroded surface (W + Ta always exposed to plasma, W largely shadowed). A further comparison where the SIMS deuterium concentration is obtained by calibrating the measurements against NRA values is also presented. For the tungsten samples, where no Ta induced matrix effects are present, the two methods are almost equivalent.The results presented show the potential of the method provided that the standards used for the calibration reproduce faithfully the matrix nature of the samples.

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

    International Nuclear Information System (INIS)

    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.

  7. Influence of externally applied magnetic perturbations on neoclassical tearing modes at ASDEX Upgrade

    International Nuclear Information System (INIS)

    The influence of externally applied magnetic perturbations (MPs) on neoclassical tearing modes (NTM) and the plasma rotation in general is investigated at the ASDEX Upgrade tokamak (AUG). The low n resonant components of the applied field exert local torques and influence the stability of NTMs. The non-resonant components of the error field do not influence MHD modes directly but slow down the plasma rotation globally due to a neoclassical toroidal viscous torque (NTV). Both components slow down the plasma rotation, which in consequence increases the probability for the appearance of locked modes. To investigate the impact of externally applied MPs on already existing modes and the influence on the rotation profile, experimental observations are compared to modelling results. The model used here solves a coupled equation system that includes the Rutherford equation and the equation of motion, taking into account the resonant effects and the resistive wall. It is shown that the NTV torque can be neglected in this modelling. To match the experimental frequency evolution of the mode the MP field strength at the resonant surface has to be increased compared to the vacuum approximation. This leads to an overestimation of the stabilizing effect on the NTMs. The reconstruction of the entire rotation profile via the equation of motion including radial dependencies, confirms that the NTV is negligibly small and that small resonant torques at different resonant surfaces have the same effect as one large one. This modelling suggests that in the experiment resonant torques at different surfaces are acting and slowing down the plasma rotation requiring a smaller torque at the specific resonant surface of the NTM. This additionally removes the overestimated influence on the island stability, whereas the braking of the island's rotation is caused by the sum of all torques. Consequently, to describe the effect of MPs on the evolution of one island, all other islands and the

  8. Real-time diagnostics at ASDEX Upgrade-Architecture and operation

    International Nuclear Information System (INIS)

    Diagnostics at ASDEX Upgrade have available a very large number of highly developed measuring channels. The prospect of making this wealth of information usable for plasma optimisation led to the implementation of a number of diagnostics running data acquisition in real-time (RT). Ultimately, this development aims to achieve a network of intelligent diagnostics delivering analysed data for high-level plasma performance control such as profile shaping and NTM stabilisation. The new RT diagnostics consist of standard industrial 19 in. servers organised in clusters and running a standard UNIX multiprocessor RT-capable operating system (RT OS). Built-to-purpose computer interface cards deliver data (e.g. via serial links) from the data acquisition (DAQ) front-ends directly into the main memory of the DAQ servers. An RT data analysis task immediately following the running direct memory access (DMA) data transfers processes the data and delivers the results to follow-up systems in the control chain. Whereas the first systems were implemented in a simple just a bunch of computers (JBOC) configuration being operated as a number of single diagnostics, newer systems are integrated into diagnostic clusters using parallel computing techniques such as message passing interface (MPI). The paper describes the hardware (ADC front-ends, serial I/O, selection criteria and performance of the involved computer busses and systems) and software (DAQ, DA, RT OS, MPI) architecture of the assembled systems. Benchmark results for DAQ and MPI bandwidth and latencies as well as for the behaviour of the RT OS will be given

  9. 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.

  10. 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.

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

    International Nuclear Information System (INIS)

    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.)

  12. Influence of Alfven eigenmodes and ion cyclotron heating on the fast-ion distribution in the ASDEX Upgrade tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Weiland, Markus; Geiger, Benedikt; Bilato, Roberto; Schneider, Philip; Tardini, Giovanni; Lauber, Philipp; Ryter, Francois; Schneller, Mirjam [Max-Planck-Institut fuer Plasmaphysik, Garching (Germany); Collaboration: ASDEX Upgrade Team

    2015-05-01

    Fast, supra-thermal ions are created in the tokamak ASDEX Upgrade by neutral beam injection and ion cyclotron resonance heating (ICRH) and they are needed for plasma heating and current drive. A possibility to study them is the spectroscopic observation of line radiation (fast-ion D-alpha, FIDA), which emerges from charge exchange reactions. Here, the fast ions can be distinguished from the thermal particles through there strong Doppler-shift, and their radial density profile can be measured and compared to theoretical models. An analysis of the whole Doppler spectrum yields information about the 2D velocity distribution f(v {sub parallel}, v {sub perpendicular} {sub to}). Observation from different viewing angles allows consequently a tomographic reconstruction of f(v {sub parallel}, v {sub perpendicular} {sub to}). For this purpose, the FIDA diagnostic at ASDEX Upgrade has been extended from two to five views, and the spectrometer setup was improved to allow a simultaneous measurement of blue and red Doppler shifts. These recently developed diagnostic capabilities are used to study changes in the fast-ion distribution, which are caused by Alfven eigenmodes. Moreover, the further acceleration of fast ions through 2{sup nd} harmonic ICRH is investigated and compared to theoretical predictions.

  13. 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.)

  14. Measurements of the fast-ion distribution function at ASDEX upgrade by collective Thomson scattering (CTS) using active and passive views

    DEFF Research Database (Denmark)

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

    2015-01-01

    Collective Thomson scattering (CTS) can provide measurements of the confined fast-ion distribution function resolved in space, time and 1D velocity space. On ASDEX Upgrade, the measured spectra include an additional signal which previously has hampered data interpretation. A new set-up using two...

  15. 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 pro...

  16. Assessment of compatibility of ICRF antenna operation with full W wall in ASDEX Upgrade

    International Nuclear Information System (INIS)

    The compatibility of ICRF (ion cyclotron range of frequencies) antenna operation with high-Z plasma facing components is assessed in ASDEX Upgrade (AUG) with its tungsten (W) first wall. The mechanism of ICRF-related W sputtering was studied by various diagnostics including the local spectroscopic measurements of W sputtering yield YW on antenna limiters. Modification of one antenna with triangular shields, which cover the locations where long magnetic field lines pass only one out of two (0π)-phased antenna straps, did not influence the locally measured YW values markedly. In the experiments with antennas powered individually, poloidal profiles of YW on limiters of powered antennas show high YW close to the equatorial plane and at the very edge of the antenna top. The YW-profile on an unpowered antenna limiter peaks at the location projecting to the top of the powered antenna. An interpretation of the YW measurements is presented, assuming a direct link between the W sputtering and the sheath driving RF voltages deduced from parallel electric near-field (E||) calculations and this suggests a strong E|| at the antenna limiters. However, uncertainties are too large to describe the YW poloidal profiles. In order to reduce ICRF-related rise in W concentration CW, an operational approach and an approach based on calculations of parallel electric fields with new antenna designs are considered. In the operation, a noticeable reduction in YW and CW in the plasma during ICRF operation with W wall can be achieved by (a) increasing plasma-antenna clearance; (b) strong gas puffing; (c) decreasing the intrinsic light impurity content (mainly oxygen and carbon in AUG). In calculations, which take into account a realistic antenna geometry, the high E|| fields at the antenna limiters are reduced in several ways: (a) by extending the antenna box and the surrounding structures parallel to the magnetic field; (b) by increasing the average strap-box distance, e.g. by increasing the

  17. Confinement of 'Improved H-Modes' in the All-Tungsten ASDEX Upgrade

    International Nuclear Information System (INIS)

    Full text: 'Improved H-mode' discharges in ASDEX Upgrade (AUG) are characterized by enhanced confinement factors H98 > 1, βN =2 - 3.5 and a q-profile with almost zero shear in the core of the plasma at q(0) ∼ 1. One of the major goals of the AUG tungsten programme has been to demonstrate the compatibility of such high performance scenarios with an all-W wall. After the all-W AUG was boronised a clear reduction of the concentration of light impurities such as carbon and oxygen (C: 0.1-1%, O< 0.1%) was observed. The radiated power decreased, especially in the divertor, and the thermal load on the W-coated divertor tiles reached values above technical capabilities. Therefore, high performance discharges in the boronized AUG were only conducted with active cooling of the divertor plasma by enhancing the radiation with N seeding. As a positive surprise it turned out that N seeding does not only protect the divertor tiles, but also improves significantly the energy confinement. This is a reproducible effect which holds for all D fuelling rates under both freshly boronised and unboronised conditions. In contrast to earlier studies of improved confinement following impurity seeding, density peaking, which would be detrimental in an all-W device, can be excluded as a contributor. The main contribution is the increase in the plasma temperature both in the core and in the edge. Stability analyses of comparable discharges with and without N seeding using the GS2 and the GENE codes highlight the role of deuterium dilution in the reduction of the core ion heat transport due to the ITG mode, which is dominant under the experimental conditions. The reduced core heat transport, however, explains the experimentally observed total confinement improvement only to a certain extent. This paper will deal with the present status of AUG plasma operation of 'improved H-Mode' scenarios at optimized performance with boronized and unboronized tungsten walls. It will focus on confinement

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

    International Nuclear Information System (INIS)

    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

  19. Avoidance of Disruptions at High βN in ASDEX Upgrade with off-Axis ECRH

    International Nuclear Information System (INIS)

    Full text: The control of disruptions in tokamak plasmas by means of electron cyclotron resonance heating (ECRH) has been addressed in several machines. The technique is based on the stabilization of magnetohydrodynamic (MHD) modes occurring at a disruption through the localized injection of ECRH on a resonant surface. A delay in the occurrence of disruption has been achieved in some cases and complete avoidance in other cases. So far, these experiments have dealt with L-mode plasmas. The first experiments of this type carried out in H-mode plasmas are described in this paper. Delay and/or complete avoidance of disruptions has been achieved in ASDEX Upgrade using localized injection of ECRH (1.5 MW) in a high βN scenario (1 MA, 2.2 T, with NBI (7.5 MW)). In these discharges (at relatively low q95 and low density) neoclassical tearing modes (NTMs) are excited and when they lock a disruption occurs. The same scheme used in previous disruption avoidance experiments in FTU and AUG has been applied: as soon as the disruption precursor signal (loop voltage and/or locked mode detector) reaches the preset threshold, the ECRH power is triggered by real time control. A poloidal scan in deposition location has been performed by varying the poloidal angles of the launching mirrors in different discharges. Complete avoidance is achieved when the power is injected close to the q = 3/2 surface: in this case multiple unlocking of MHD modes occurs after ECRH application. When ECRH is injected at more external locations, the discharges, although not disrupting immediately as in the reference case, show no mode unlocking and eventually disrupt. For injection at inner locations the discharge disrupts as in the reference case. The absorption of ECRH is therefore found to modify the sequence of events occurring at a disruption by acting locally (through a change in resistivity) on the gradient of plasma current which is supposed to be the main drive of the island amplitude growth rate

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

    International Nuclear Information System (INIS)

    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

  1. 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

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

    International Nuclear Information System (INIS)

    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 fELM 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

  3. Global migration of {sup 13}C impurities in high-density L-mode plasmas in ASDEX Upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Hakola, A., E-mail: antti.hakola@vtt.fi [VTT, Association EURATOM-Tekes, P.O. Box 1000, 02044 VTT (Finland); Koivuranta, S.; Likonen, J. [VTT, Association EURATOM-Tekes, P.O. Box 1000, 02044 VTT (Finland); Groth, M.; Kurki-Suonio, T.; Lindholm, V.; Miettunen, J. [Aalto University, Association EURATOM-Tekes, P.O. Box 14100, 00076 AALTO (Finland); Krieger, K.; Mayer, M.; Müller, H.W.; Neu, R.; Rohde, V. [Max-Planck-Institut für Plasmaphysik, EURATOM Association, Boltzmannstr. 2, 85748 Garching (Germany); Petersson, P. [Royal Institute of Technology, Association EURATOM-VR, Teknikringen 31, 10044 Stockholm (Sweden)

    2013-07-15

    We have studied the migration of {sup 13}C in ASDEX Upgrade after a global impurity injection experiment in 2011. The main chamber was observed to be the largest deposition region for carbon: almost 35% of the injected atoms end up there. Moreover, gaps between wall tiles account for surface densities which are comparable to those on the plasma-facing surfaces. SOLPS modeling of the experiment produced a set of background plasmas and poloidal flow profiles for simulating the transport of {sup 13}C with ASCOT; a match with measured deposition, however, required using an imposed flow profile. ASCOT reproduced the observed localized deposition at the outer midplane but work is needed to explain the measured deposition at the inner side of the torus and at the top of the vessel.

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

    International Nuclear Information System (INIS)

    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.

  5. High resolution scanning transmission electron microscopy (HR STEM) analysis of re-deposited layer on ASDEX Upgrade tile

    Energy Technology Data Exchange (ETDEWEB)

    Rasinski, M., E-mail: mrasin@o2.pl [Warsaw University of Technology, Faculty of Material Science and Engineering, Woloska 141, 02-507 Warsaw (Poland); Fortuna-Zalesna, E. [Warsaw University of Technology, Faculty of Material Science and Engineering, Woloska 141, 02-507 Warsaw (Poland); Mayer, M.; Neu, R. [Max-Planck-Institut fuer Plasmaphysik, Euratom Association, Boltzmannstrasse 2, D-85748 Garching (Germany); Plocinski, T.; Lewandowska, M.; Kurzydlowski, K.J. [Warsaw University of Technology, Faculty of Material Science and Engineering, Woloska 141, 02-507 Warsaw (Poland)

    2011-10-15

    Erosion and re-deposition of plasma-facing components (PFCs) is one of the most important issues in fusion devices and as such it is an area of interest for many research groups. However, the structure and composition of re-deposited layers as well as the mechanism and condition of their formation are not yet fully described and understood. In the present study, the structure and the composition of co-deposited layers, which developed at the outer divertor strike point tiles in ASDEX Upgrade during the 2009 campaign were examined. High resolution scanning transmission electron microscopy (HRSTEM) combined with energy-dispersive X-ray spectroscopy (EDS) and electron energy loss spectroscopy (EELS) have been used to identify deposits composition and morphology. Tungsten foam like structure and co-deposits rich in tungsten, oxygen, carbon, boron and nitrogen were observed.

  6. High resolution scanning transmission electron microscopy (HR STEM) analysis of re-deposited layer on ASDEX Upgrade tile

    International Nuclear Information System (INIS)

    Erosion and re-deposition of plasma-facing components (PFCs) is one of the most important issues in fusion devices and as such it is an area of interest for many research groups. However, the structure and composition of re-deposited layers as well as the mechanism and condition of their formation are not yet fully described and understood. In the present study, the structure and the composition of co-deposited layers, which developed at the outer divertor strike point tiles in ASDEX Upgrade during the 2009 campaign were examined. High resolution scanning transmission electron microscopy (HRSTEM) combined with energy-dispersive X-ray spectroscopy (EDS) and electron energy loss spectroscopy (EELS) have been used to identify deposits composition and morphology. Tungsten foam like structure and co-deposits rich in tungsten, oxygen, carbon, boron and nitrogen were observed.

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

    International Nuclear Information System (INIS)

    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)

  8. Simulations of gas puff effects on edge density and ICRF coupling in ASDEX upgrade using EMC3-Eirene

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, W., E-mail: wei.zhang@ipp.mpg.de [Applied Physics Department, University of Ghent, Ghent (Belgium); Max-Planck-Institut für Plasmaphysik, Garching (Germany); Institute of Plasma Physics, Chinese Academy of Sciences, Hefei (China); Lunt, T.; Bobkov, V.; Coster, D.; Brida, D. [Max-Planck-Institut für Plasmaphysik, Garching (Germany); Noterdaeme, J.-M. [Applied Physics Department, University of Ghent, Ghent (Belgium); Max-Planck-Institut für Plasmaphysik, Garching (Germany); Jacquet, P. [CCFE, Culham Science Centre, Abingdon (United Kingdom); Feng, Y. [Max-Planck-Institut für Plasmaphysik, Greifswald (Germany)

    2015-12-10

    Simulations were carried out with the 3D plasma transport code EMC3-EIRENE, to study the deuterium gas (D{sub 2}) puff effects on edge density and the coupling of Ion Cyclotron Range of Frequency (ICRF) power in ASDEX Upgrade. Firstly we simulated an inter-ELM phase of an H-mode discharge with a moderate (1.2 × 10{sup 22} electrons/s) lower divertor gas puff. Then we changed the gas source positions to the mid-plane or top of machine while keeping other conditions the same. Cases with different mid-plane or top gas valves are investigated. Our simulations indicate that compared to lower divertor gas puffing, the mid-plane gas puff can enhance the local density in front of the antennas most effectively, while a rather global (toroidally uniform) but significantly smaller enhancement is found for top gas puffing. Our results show quantitative agreement with the experiments.

  9. Comparison of experiment and models of geodesic acoustic mode frequency and amplitude geometric scaling in ASDEX Upgrade

    Science.gov (United States)

    Simon, P.; Conway, G. D.; Stroth, U.; Biancalani, A.; Palermo, F.; the ASDEX Upgrade Team

    2016-04-01

    In a set of dedicated ASDEX Upgrade shape-scan experiments, the influence of plasma geometry on the frequency and amplitude behaviour of the geodesic acoustic mode (GAM), measured by Doppler reflectometry, is studied. In both limiter and divertor configurations, the plasma elongation was varied between circular and highly elongated states (1.1effects. The experimentally observed effect of decreasing {ω\\text{GAM}} with increasing κ is predicted by most models. Other geometric factors, such as inverse aspect ratio ε and Shafranov shift gradient {Δ\\prime} are also seen to be influential in determining a reliable lower {ω\\text{GAM}} boundary. The GAM amplitude is found to vary with boundary elongation {κ\\text{b}} and safety factor q. The collisional damping is compared to multiple models for the collisionless damping. Collisional damping appears to play a stronger role in the divertor configuration, while collisional and collisionless damping both may contribute to the GAM amplitude in the limiter configuration.

  10. Sawtooth control using electron cyclotron current drive in the presence of energetic particles in high performance ASDEX Upgrade plasmas

    CERN Document Server

    Chapman, I T; Maraschek, M; McCarthy, P J; Tardini, G

    2013-01-01

    Sawtooth control using steerable electron cyclotron current drive (ECCD) has been demonstrated in ASDEX Upgrade plasmas with a significant population of energetic ions in the plasma core and long uncontrolled sawtooth periods. The sawtooth period is found to be minimised when the ECCD resonance is swept to just inside the q = 1 surface. By utilising ECCD inside q = 1 for sawtooth control, it is possible to avoid the triggering of neoclassical tearing modes, even at significnatly higher pressure than anticipated in the ITER baseline scenario. Operation at 25% higher normalised pressure has been achieved when only modest ECCD power is used for sawtooth control compared to identical discharges without sawtooth control when neo-classical tearing modes are triggered by the sawteeth. Modelling suggests that the destabilisation arising from the change in the local magnetic shear caused by the ECCD is able to compete with the stabilising influence of the energetic particles inside the q = 1 surface.

  11. Simulations of gas puff effects on edge density and ICRF coupling in ASDEX upgrade using EMC3-Eirene

    International Nuclear Information System (INIS)

    Simulations were carried out with the 3D plasma transport code EMC3-EIRENE, to study the deuterium gas (D2) puff effects on edge density and the coupling of Ion Cyclotron Range of Frequency (ICRF) power in ASDEX Upgrade. Firstly we simulated an inter-ELM phase of an H-mode discharge with a moderate (1.2 × 1022 electrons/s) lower divertor gas puff. Then we changed the gas source positions to the mid-plane or top of machine while keeping other conditions the same. Cases with different mid-plane or top gas valves are investigated. Our simulations indicate that compared to lower divertor gas puffing, the mid-plane gas puff can enhance the local density in front of the antennas most effectively, while a rather global (toroidally uniform) but significantly smaller enhancement is found for top gas puffing. Our results show quantitative agreement with the experiments

  12. 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

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

    International Nuclear Information System (INIS)

    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

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

    International Nuclear Information System (INIS)

    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

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

    International Nuclear Information System (INIS)

    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 Er. The gradients in Er 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 Er profile. The radial electric field has been derived from charge exchange spectra measured on different impurity species including He2+, B5+, C6+ and Ne10+. The resulting Er 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 Er profile forms a deep, negative (i.e. directed towards the plasma center

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

    International Nuclear Information System (INIS)

    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

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

    International Nuclear Information System (INIS)

    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)

  18. Laboratory astrophysics on ASDEX Upgrade: Measurements and analysis of K-shell O, F, and Ne spectra in the 9 - 20 A region

    Science.gov (United States)

    Hansen, S. B.; Fournier, K. B.; Finkenthal, M. J.; Smith, R.; Puetterich, T.; Neu, R.

    2006-01-01

    High-resolution measurements of K-shell emission from O, F, and Ne have been performed at the ASDEX Upgrade tokamak in Garching, Germany. Independently measured temperature and density profiles of the plasma provide a unique test bed for model validation. We present comparisons of measured spectra with calculations based on transport and collisional-radiative models and discuss the reliability of commonly used diagnostic line ratios.

  19. 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

  20. A new diagnostic for ASDEX upgrade edge ion temperatures by lithium-beam charge exchange recombination spectroscopy

    International Nuclear Information System (INIS)

    This thesis work investigates the measurement of ion temperatures at the edge of a magnetically confined plasma used for fusion research at the ASDEX Upgrade tokamak operated by Max-Planck-Institut fuer Plasmaphysik in Garching. The H-mode plasma regime, default scenario of the next step experiment ITER, is characterized by an edge transport barrier, which is not yet fully explained by theory. Experimentally measured edge ion temperature profiles will help to test and develop models for these barriers. Transport theory on a basic level is introduced as background and motivation for the new diagnostic. The standard model for an edge plasma instability named ''edge localized mode'' (ELM) observed in H-mode is described. The implementation of a new diagnostic for ion temperature measurements with high spatial resolution in the plasma edge region, its commissioning and the validation of the measurements comprises the main part of this work. The emission of line radiation induced by charge exchange processes between lithium atoms injected by a beam source and fully ionized impurities (of C and He) is observed with a detection system consisting of spectrometers and fast cameras. Due to the narrow beam (1 cm) and closely staggered optical fibers (6 mm), unprecedented spatial resolution of edge ion temperatures in all major plasma regimes of the ASDEX Upgrade tokamak was achieved. The spectral width of the line radiation (He II at 468.5 nm and C VI at 529.0 nm) contains information about the local ion temperature from thermal Doppler-broadening, which is the dominant broadening mechanism for these lines. The charge-exchange contribution to the total line radiation locally generated by the lithium is determined by gating the beam. Fitting a Gaussian model function to the local line radiation results in absolute line widths which can be directly converted into a temperature. The equilibration of impurities with the main plasma is fast enough that the assumption of nearly

  1. TSC Modelling of Major Disruption and VDE Events in NSTX and ASDEX-Upgrade and Predictions for ITER

    International Nuclear Information System (INIS)

    Full text: In the 2008 IAEA FEC, we had presented results of TSC simulations of fast MDs and slow VDEs and compared these simulation results with that obtained from DINA modelling. These results largely showed similar plasma behaviour, although somewhat differed in the predictions for the plasma current quench times and halo current magnitudes. Thus, it was decided to update both the models after benchmarking them with experimental observations in NSTX and ASDEX Upgrade (AUG) devices and use the updated codes to make more accurate predictions for ITER. Also ITER machine has undergone significant changes in the last year, e.g., in the vacuum vessel, blanket modules, central solenoid, divertor dome structure, addition of in-vessel control coils and so on, which affect the vertical evolution and disruption behaviour of the plasma. We present in this paper the TSC modelling of the VDE and MD events in NSTX and AUG devices, which help in improving and validating the models used in the code. The predictive modelling results for ITER with the updated TSC code, including the force predictions, are also presented. (author)

  2. Simulations of fast ion wall loads in ASDEX Upgrade in the presence of magnetic perturbations due to ELM mitigation coils

    CERN Document Server

    Asunta, Otto; Kurki-Suonio, Taina; Koskela, Tuomas; Sipilä, Seppo; Snicker, Antti; Garcia-Muñoz, Manuel

    2015-01-01

    The effect of ASDEX Upgrade (AUG) ELM mitigation coils on fast ion wall loads was studied with the fast particle following Monte Carlo code ASCOT. Neutral beam injected (NBI) particles were simulated in two AUG discharges both in the presence and in the absence of the magnetic field perturbation induced by the eight newly installed in-vessel coils. In one of the discharges (#26476) beams were applied individually, making it a useful basis for investigating the effect of the coils on different beams. However, no ELM mitigation was observed in #26476, probably due to the low plasma density. Therefore, another discharge (#26895) demonstrating clear ELM mitigation was also studied. The magnetic perturbation due to the in-vessel coils has a significant effect on the fast particle confinement, but only when total magnetic field, $B_{tot}$, is low. When $B_{tot}$ was high, the perturbation did not increase the losses, but merely resulted in redistribution of the wall power loads. Hence, it seems to be possible to ac...

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

    International Nuclear Information System (INIS)

    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.

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

    International Nuclear Information System (INIS)

    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.

  5. 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.

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

    International Nuclear Information System (INIS)

    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)].

  7. Fast-ion redistribution and loss due to edge perturbations in the ASDEX Upgrade, DIII-D and KSTAR tokamaks

    International Nuclear Information System (INIS)

    The impact of edge localized modes (ELMs) and externally applied resonant and non-resonant magnetic perturbations (MPs) on fast-ion confinement/transport have been investigated in the ASDEX Upgrade (AUG), DIII-D and KSTAR tokamaks. Two phases with respect to the ELM cycle can be clearly distinguished in ELM-induced fast-ion losses. Inter-ELM losses are characterized by a coherent modulation of the plasma density around the separatrix while intra-ELM losses appear as well-defined bursts. In high collisionality plasmas with mitigated ELMs, externally applied MPs have little effect on kinetic profiles, including fast-ions, while a strong impact on kinetic profiles is observed in low-collisionality, low q95 plasmas with resonant and non-resonant MPs. In low-collisionality H-mode plasmas, the large fast-ion filaments observed during ELMs are replaced by a 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 prompt loss signal without MPs. A clear synergy in the overall fast-ion transport is observed between MPs and neoclassical tearing modes. Measured fast-ion losses are typically on banana orbits that explore the entire pedestal/scrape-off layer. The fast-ion response to externally applied MPs presented here may be of general interest for the community to better understand the MP field penetration and overall plasma response. (paper)

  8. An experimental investigation on the high density transition of the Scrape-off Layer transport in ASDEX Upgrade

    CERN Document Server

    Carralero, D; Müller, H W; Manz, P; deMarne, P; Müller, S H; Reimold, F; Stroth, U; Wischmeier, M; Wolfrum, E

    2014-01-01

    A multidiagnostic approach, utilizing Langmuir probes in the midplane, X-point and divertor walls, along with Lithium beam and infrared measurements is employed to evaluate the evolution of the Scrape-off Layer (SOL) of ASDEX Upgrade across the L-mode density transition leading to the formation of a density shoulder. The flattening of the SOL density profiles is linked to a regime change of filaments, which become faster and larger, and to a similar flattening of the $q_{\\parallel}$ profile. This transition is related to the beginning of outer divertor detachment and leads to the onset of a velocity shear layer in the SOL. Experimental measurements are in good agreement with several filament models which describe the process as a transition from conduction to convection-dominated SOL perpendicular transport caused by an increase of parallel collisionality. These results could be of great relevance since both ITER and DEMO will feature detached divertors and densities largely over the transition values, and mi...

  9. Quantification of the impact of large and small-scale instabilities on the fast-ion confinement in ASDEX Upgrade

    Science.gov (United States)

    Geiger, B.; Weiland, M.; Mlynek, A.; Reich, M.; Bock, A.; Dunne, M.; Dux, R.; Fable, E.; Fischer, R.; Garcia-Munoz, M.; Hobirk, J.; Hopf, C.; Nielsen, S.; Odstrcil, T.; Rapson, C.; Rittich, D.; Ryter, F.; Salewski, M.; Schneider, P. A.; Tardini, G.; Willensdorfer, M.

    2015-01-01

    The confinement fast ions, generated by neutral beam injection (NBI), has been investigated at the ASDEX Upgrade tokamak. In plasmas that exhibit strong sawtooth crashes, a significant sawtooth-induced internal redistribution of mainly passing fast ions is observed, which is in very good agreement with the theoretical predictions based on the Kadomtsev model. Between the sawtooth crashes, the fishbone modes are excited which, however, do not cause measurable changes in the global fast-ion population. During experiments with on- and off-axis NBI and without strong magnetohydrodynamic (MHD) modes, the fast-ion measurements agree very well with the neo-classical predictions. This shows that the MHD-induced (large-scale), as well as a possible turbulence-induced (small-scale) fast-ion transport is negligible under these conditions. However, in discharges performed to study the off-axis NBI current drive efficiency with up to 10 MW of heating power, the fast-ion measurements agree best with the theoretical predictions that assume a weak level anomalous fast-ion transport. This is also in agreement with measurements of the internal inductance, a Motional Stark Effect diagnostic and a novel polarimetry diagnostic: the fast-ion driven current profile is clearly modified when changing the NBI injection geometry and the measurements agree best with the predictions that assume weak anomalous fast-ion diffusion.

  10. Sawtooth control using electron cyclotron current drive in the presence of energetic particles in high performance ASDEX Upgrade plasmas

    International Nuclear Information System (INIS)

    Sawtooth control using steerable electron cyclotron current drive (ECCD) has been demonstrated in ASDEX Upgrade plasmas with a significant population of energetic ions in the plasma core and long uncontrolled sawtooth periods. The sawtooth period is found to be minimized when the ECCD resonance is swept to just inside the q = 1 surface. By utilizing ECCD inside q = 1 for sawtooth control, it is possible to avoid the triggering of neoclassical tearing modes (NTMs), even at significantly higher pressure than anticipated in the ITER baseline scenario. Operation at 25% higher normalized pressure has been achieved when only modest ECCD power is used for sawtooth control compared to identical discharges without sawtooth control when NTMs are triggered by the sawteeth. Modelling suggests that the destabilization arising from the change in the local magnetic shear caused by the ECCD is able to compete with the stabilizing influence of the energetic particles inside the q = 1 surface. (paper)

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

    International Nuclear Information System (INIS)

    Highlights: ► The high sustained data rates transferring measured data from periphery into memory of computers. ► The achieved low latency in real-time interrupt handling under Solaris 10. ► The new prototype of an even more powerful 2nd generation SIO II device. ► 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.

  12. 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

  13. 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), s. 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 Impact factor: 1.614, year: 2014 http://scitation.aip.org/content/aip/journal/rsi/87/4/10.1063/1.4945797

  14. Experimental analysis and WallDYN simulations of the global nitrogen migration in ASDEX Upgrade L-mode discharges

    Science.gov (United States)

    Meisl, G.; Schmid, K.; Oberkofler, M.; Krieger, K.; Lisgo, S. W.; Aho-Mantila, L.; Reimold, F.; Lunt, T.; ASDEX Upgrade Team

    2016-03-01

    This work presents ASDEX Upgrade experiments, where the nitrogen deposition and re-erosion on divertor manipulator samples and the effect of its transport through the plasma were studied. These results are compared to WallDYN-DIVIMP simulations based on SOLPS plasma backgrounds and employing an improved WallDYN model, which includes the effusion of nitrogen from saturated surfaces. On one hand, this allows the WallDYN code and the new saturation model with a comprehensive data set to be benchmarked, on the other hand the simulations help in the interpretation of the experimental results. Both, experimental results and simulations, show that the N content in the region of the outer strike line reaches its steady-state value within one discharge. The simulations also reproduce the experimentally observed nitrogen content in samples exposed to N2-seeded discharges. With respect to the boron deposition, the nitrogen deposition in a non-seeded discharge and the re-erosion of nitrogen discrepancies to the WallDYN-DIVIMP simulations are observed. Based on SDTrimSP simulations, these are attributed to the missing depth resolution of the WallDYN surface model. A detailed comparison of spectroscopic measurements to WallDYN simulations, based on a novel synthetic spectroscopy diagnostic for WallDYN, shows that the nitrogen fluxes in the plasma are well described by the simulations. From a comparison of several WallDYN-DIVIMP simulations employing customized onion-skin model plasma backgrounds the physical processes controlling the nitrogen concentration in the core plasma and the applicability of onion-skin model plasma backgrounds are discussed. From these simulations the private flux zone with the gas valve, the outer baffle and the high field side main wall are identified as the main sources for the nitrogen content of the core plasma.

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

    International Nuclear Information System (INIS)

    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)

  16. High power ECRH and ECCD in moderately collisional ASDEX Upgrade Hmodes and status of EC system upgrade

    Directory of Open Access Journals (Sweden)

    Stober J.

    2015-01-01

    Full Text Available This contribution deals with H-modes with significant heat exchange between electrons and ions, but which can still show large differences between electron and ion-temperatures especially inside half minor radius. These conditions are referred to as moderately collisional. A systematic study shows that an increasing fraction of electron heating increases the transport in the ion channel mainly due to the dependence of the ITG dominated ion transport on the ratio Te/Ti in agreement with modeling. The rotational shear in the plasmas under study was so small that it hardly influences ITG stability, such that variations of the rotation profile due to a change of the heating method were of minor importance. These findings connect to studies of advanced tokamak scenarios using ECCD as a tool to modify the q-profile. The electron heating connected to the ECCD tends to increase the transport in the ion channel quite in contrast to the goal to operate at reduced current but with increased confinement. The confinement only increases as the fraction of ion heating is increased by adding more NBI. An ITER case was modeled as well. Due to the larger value of νei ・ τE the ratio Te/Ti is only moderately reduced even with strong electron heating and the confinement reduction is small even for the hypothetic case of using only ECRH as additional heating. Finally the paper discusses the ongoing upgrade of the AUG ECRH-system.

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

    International Nuclear Information System (INIS)

    We 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 >1250 Torr l (equivalent to 150 x 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 l (equivalent to 50 x plasma particle content) plasma inventories at a maximum fueling efficiency ∝1. Data from the ASDEX Upgrade tokamak suggests qualitative behavior of wall retention and fueling efficiency similar to DIII-D. (orig.)

  18. 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.

  19. Toroidal modelling of RMP response in ASDEX Upgrade: coil phase scan, q 95 dependence, and toroidal torques

    Science.gov (United States)

    Liu, Yueqiang; Ryan, D.; Kirk, A.; Li, Li; Suttrop, W.; Dunne, M.; Fischer, R.; Fuchs, J. C.; Kurzan, B.; Piovesan, P.; Willensdorfer, M.; the ASDEX Upgrade Team; the EUROfusion MST1 Team

    2016-05-01

    The plasma response to the vacuum resonant magnetic perturbation (RMP) fields, produced by the ELM control coils in ASDEX Upgrade experiments, is computationally modelled using the MARS-F/K codes (Liu et al 2000 Phys. Plasmas 7 3681, Liu et al 2008 Phys. Plasmas 15 112503). A systematic investigation is carried out, considering various plasma and coil configurations as in the ELM control experiments. The low q plasmas, with {{q}95}∼ 3.8 (q 95 is the safety factor q value at 95% of the equilibrium poloidal flux), responding to low n (n is the toroidal mode number) field perturbations from each single row of the ELM coils, generates a core kink amplification effect. Combining two rows, with different toroidal phasing, thus leads to either cancellation or reinforcement of the core kink response, which in turn determines the poloidal location of the peak plasma surface displacement. The core kink response is typically weak for the n  =  4 coil configuration at low q, and for the n  =  2 configuration but only at high q ({{q}95}∼ 5.5 ). A phase shift of around 60 degrees for low q plasmas, and around 90 degrees for high q plasmas, is found in the coil phasing, between the plasma response field and the vacuum RMP field, that maximizes the edge resonant field component. This leads to an optimal coil phasing of about 100 (‑100) degrees for low (high) q plasmas, that maximizes both the edge resonant field component and the plasma surface displacement near the X-point of the separatrix. This optimal phasing closely corresponds to the best ELM mitigation observed in experiments. A strong parallel sound wave damping moderately reduces the core kink response but has minor effect on the edge peeling response. For low q plasmas, modelling shows that both the resonant electromagnetic torque and the neoclassical toroidal viscous (NTV) torque (due to the presence of 3D magnetic field perturbations) contribute to the toroidal flow damping, in particular near the

  20. Fast-ion losses induced by ELMs and externally applied magnetic perturbations in the ASDEX Upgrade tokamak

    International Nuclear Information System (INIS)

    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 q95 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

  1. 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

  2. Novel free-boundary equilibrium and transport solver with theory-based models and its validation against ASDEX Upgrade current ramp scenarios

    International Nuclear Information System (INIS)

    Tokamak scenario development requires an understanding of the properties that determine the kinetic profiles in non-steady plasma phases and of the self-consistent evolution of the magnetic equilibrium. Current ramps are of particular interest since many transport-relevant parameters explore a large range of values and their impact on transport mechanisms has to be assessed. To this purpose, a novel full-discharge modelling tool has been developed, which couples the transport code ASTRA (Pereverzev et al 1991 IPP Report 5/42) and the free boundary equilibrium code SPIDER (Ivanov et al 2005 32nd EPS Conf. on Plasma Physics vol 29C (ECA) P-5.063 and http://epsppd.epfl.ch/Tarragona/pdf/P5_063.pdf), utilizing a specifically designed coupling scheme. The current ramp-up phase can be accurately and reliably simulated using this scheme, where a plasma shape, position and current controller is applied, which mimics the one of ASDEX Upgrade. Transport of energy is provided by theory-based models (e.g. TGLF (Staebler et al 2007 Phys. Plasmas 14 055909)). A recipe based on edge-relevant parameters (Scott 2000 Phys. Plasmas 7 1845) is proposed to resolve the low current phase of the current ramps, where the impact of the safety factor on micro-instabilities could make quasi-linear approaches questionable in the plasma outer region. Current ramp scenarios, selected from ASDEX Upgrade discharges, are then simulated to validate both the coupling with the free-boundary evolution and the prediction of profiles. Analysis of the underlying transport mechanisms is presented, to clarify the possible physics origin of the observed L-mode empirical energy confinement scaling. The role of toroidal micro-instabilities (ITG, TEM) and of non-linear effects is discussed. (paper)

  3. First Studies of ITER Diagnostic Mirrors in a Tokamak with All-metal Interior: Results of First Mirror Test in ASDEX Upgrade

    International Nuclear Information System (INIS)

    Full text: In ITER, mirrors will be used as plasma-viewing elements in all optical and laser diagnostics. In the harsh environment mirror performance will degrade hampering the operation of respective diagnostics. The most adverse effect on mirrors is caused by the deposition of impurities and it is expected that the most challenging situation will occur in the divertor. With envisaged changes to all-metal plasma-facing components (PFCs) in ITER, an assessment of mirror performance in the existing divertor tokamak with all-metal PFCs is urgently needed. Such an experiment was made in the ASDEX Upgrade with all-tungsten PFCs as proposed by the International Tokamak Physics Activity (ITPA) Topical Group on Diagnostics, supported by the Specialists Working Group on First Mirrors and carried out in the frame of collaboration between Forschungszentrum Juelich and IPP Garching. Four molybdenum and four copper mirrors were mounted at the inner wall, in the dome facing the inner and outer divertor targets and in the pump-duct and exposed for seven months in ASDEX Upgrade. After exposure, degradation of the reflectivity was detected on all mirrors. The mirrors in the pump duct almost preserved their reflectivity unlike the mirrors in the dome facing the outer divertor which suffered from highest deposition and the strongest reflectivity degradation. Remarkably, only on the mirror facing the inner divertor and having very thin deposition layer of 15 nm, the carbon fraction was about 50 at.%. On all other mirrors this fraction did not exceed 20 at.%. The exposure of diagnostic mirrors in the tokamak with all-metal PFCs demonstrated a positive trend to a reduction of net deposition and minor changes in the reflectivity of mirrors located in the pump-duct far away from divertor plasmas. However, the degradation of all exposed mirrors underlines the necessity of an active mirror recovery. Urgent R&D is needed to address the lifetime issues of mirrors in ITER divertor. (author)

  4. A new B-dot probe-based diagnostic for amplitude, polarization, and wavenumber measurements of ion cyclotron range-of frequency fields on ASDEX Upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Ochoukov, R.; Bobkov, V.; Faugel, H.; Fünfgelder, H. [Max-Planck-Institut für Plasmaphysik, Boltzmannstr. 2, 85748 Garching (Germany); Noterdaeme, J.-M. [Max-Planck-Institut für Plasmaphysik, Boltzmannstr. 2, 85748 Garching (Germany); Applied Physics Department, University Gent, 9000 Gent (Belgium)

    2015-11-15

    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{sub //}) 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{sub tor}). Measurements during a strap current phasing scan in tokamak discharges reveal an upshift in k{sub //} as strap phasing is moved away from the dipole configuration. This result is the opposite of the k{sub 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{sub //}, 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

  5. M3D-C1 simulations of plasma response in ELM-mitigated ASDEX Upgrade and DIII-D discharges

    Science.gov (United States)

    Lyons, B. C.; Ferraro, N. M.; Haskey, S. R.; Logan, N. C.

    2015-11-01

    The extended magnetohydrodynamics (MHD) code M3D-C1 is used to study the time-independent, linear response of tokamak equilibria to applied, 3D magnetic perturbations. In doing so, we seek to develop a more complete understanding of what MHD phenomena are responsible for the mitigation and suppression of edge-localized modes (ELMs) and to explain why the success of ELM suppression experiments differs both within a single tokamak and across different tokamaks. We consider such experiments on ASDEX Upgrade and DIII-D. We examine how resonant and non-resonant plasma responses are affected by varying the relative magnitude and phase of sets of magnetic coils. The importance of two-fluid effects, rotation profiles, plasma β, collisionality, bootstrap current profiles, and various numerical parameters are explored. The results are verified against other MHD codes (e.g., IPEC, MARS), correlated to observations of ELM mitigation or suppression, and validated against observed magnetic responses. Work supported in part by US DOE under DE-FC02-04ER54698, DE-AC02-09CH11466, and the FES Postdoctoral Research Program.

  6. Simulations of fast ion wall loads in ASDEX Upgrade in the presence of magnetic perturbations due to ELM-mitigation coils

    International Nuclear Information System (INIS)

    The effect of ASDEX Upgrade (AUG) edge localized mode (ELM)-mitigation coils on fast ion wall loads was studied with the fast particle following Monte Carlo code ASCOT. Neutral beam injected particles were simulated in two AUG discharges both in the presence and in the absence of the magnetic field perturbation induced by the eight newly installed in-vessel coils. In one of the discharges (no. 26476) beams were applied individually, making it a useful basis for investigating the effect of the coils on different beams. However, no ELM mitigation was observed in no. 26476, probably due to the low plasma density. Therefore, another discharge (no. 26895) demonstrating clear ELM mitigation was also studied. The magnetic perturbation due to the in-vessel coils has a significant effect on the fast particle confinement, but only when total magnetic field, Btot, is low. When Btot was high, the perturbation did not increase the losses, but merely resulted in redistribution of the wall power loads. Hence, it seems to be possible to achieve ELM mitigation using in-vessel coils, while still avoiding increased fast ion losses, by simply using a strong Btot. Preliminary comparisons between simulated and experimental fast ion lost detector signals show a reasonable correspondence. (paper)

  7. 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)

    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 q95, 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 q95, which could not be tested at higher currents at JET due to limitations in heating power. (author)

  8. Localized Scrape-Off Layer density modifications by Ion Cyclotron near fields in JET and ASDEX-Upgrade L-mode plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Colas, L., E-mail: laurent.colas@cea.fr [CEA, IRFM, F-13108 Saint-Paul-Lez-Durance (France); Jacquet, Ph. [CCFE, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Van Eester, D. [LPP-ERM-KMS, TEC partner, Brussels (Belgium); Bobkov, V. [Max-Planck-Institut für Plasmaphysik, Garching (Germany); Brix, M.; Meneses, L. [CCFE, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Tamain, P. [CEA, IRFM, F-13108 Saint-Paul-Lez-Durance (France); Marsen, S. [CCFE, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Silva, C. [Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa (Portugal); Carralero, D.; Kočan, M.; Müller, H.-W. [Max-Planck-Institut für Plasmaphysik, Garching (Germany); Crombé, K.; Křivska, A. [LPP-ERM-KMS, TEC partner, Brussels (Belgium); Goniche, M. [CEA, IRFM, F-13108 Saint-Paul-Lez-Durance (France); Lerche, E. [LPP-ERM-KMS, TEC partner, Brussels (Belgium); Rimini, F.G. [CCFE, Culham Science Centre, Abingdon OX14 3DB (United Kingdom)

    2015-08-15

    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 × B{sub 0} 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.

  9. 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.

  10. Characterization of edge profiles and fluctuations in discharges with type-II and nitrogen-mitigated edge localized modes in ASDEX Upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Wolfrum, E; Bernert, M; Burckhart, A; Classen, I G J; Conway, G D; Eich, T; Fischer, R; Gude, A; Herrmann, A; Maraschek, M; McDermott, R; Puetterich, T; Wieland, B [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, Garching (Germany); Boom, J E [FOM Institute for Plasmaphysics, Rijnhuizen, Association EURATOM-FOM, Nieuwegein (Netherlands); Luhmann, N C Jr [University of California at Davis, Davis, CA95616 (United States); Park, H K [POSTECH, Pohang, Gyeongbuk, 790-784 (Korea, Republic of); Vicente, J [Associacao EURATOM/IST, Instituto de Plasmas e Fosao Nuclear - Laboratorio Associado, IST, Lisbon (Portugal); Willensdorfer, M, E-mail: e.wolfrum@ipp.mpg.de [Institute of Applied Physics, Vienna University of Technology, Association EURATOM-OEAW, Vienna (Austria)

    2011-08-15

    Edge localized modes (ELMs) with high frequency and low power loss (type-II ELMs) occur in high triangularity, near double null configurations in ASDEX Upgrade with full tungsten plasma facing components. The transition from type-I to type-II ELMs is shown to occur above a collisionality threshold. For the first time the characteristic MHD fluctuations around 40 kHz have been localized. The fluctuations are observed in a wide region extending from the pedestal inward to normalized poloidal radius {rho}{sub pol} = 0.7. Their amplitudes on the low-field side of the plasma exhibit maxima above and below the mid-plane. The fluctuations move in the electron drift direction and lead to a reduced edge electron temperature gradient. The reduction in the edge pressure gradient is connected with these MHD fluctuations, which affect the electron temperature but not the electron density profiles. A comparison with nitrogen-mitigated type-I ELMs in the same plasma shape shows that core profiles are also affected. The electron temperature profile is self-similar for type-I and nitrogen-mitigated type-I ELMs but is not self-similar in the case of type-II ELMs.

  11. Direct observations of L-I-H and H-I-L transitions with the X-point reciprocating probe in ASDEX Upgrade

    International Nuclear Information System (INIS)

    A reciprocating Langmuir probe was used to directly measure the behavior of turbulence and flows in the X-point region during transitions between low-(L) and high-confinement (H) mode in ASDEX Upgrade. The probe traverses the divertor horizontally in 140 ms, typically 2–5 cm below the X-point. Toroidal Mach number, density, floating potential (ϕf), and electron temperature (Te) are measured. In the regime accessible to the probe (Pinj19 m−2), the L-H transition features an intermediate phase (I-phase), characterized by limit-cycle oscillations at 0.5–3 kHz [Conway et al., Phys. Rev. Lett. 106, 065001 (2011)]. The probe measurements reveal that this pulsing affects both the density and the toroidal Mach number. It is present in both the low-(LFS) and high-field sides (HFS) of the scrape-off layer, while high-amplitude broadband turbulence usually dominates the private-flux region. Profile comparisons between L-mode and I-phase show lower density in pulsing regions and small shifts in Te, directed oppositely on LFS and HFS, which are compensated by shifts in ϕf to yield a surprisingly unchanged plasma potential profile. Directly observed L-I-phase transitions reveal that the onset of the pulsing is preceded by a fast 50% density drop in the HFS X-point region. Back transitions to L-mode occur essentially symmetrically, with the pulsing stopping first, followed by a fast recovery to L-mode density levels in the divertor

  12. Outer divertor of ASDEX Upgrade in low-density L-mode discharges in forward and reversed magnetic field: II. Analysis of local impurity migration

    International Nuclear Information System (INIS)

    Part I (Aho-Mantila L. et al 2012 Nucl. Fusion 52 103006) presented a detailed analysis of outer divertor plasma conditions in low-density L-mode discharges in ASDEX Upgrade. In this paper, we analyse the local migration of carbon that originates from 13CH4 injected into these plasmas from the vertical outer target. Notable changes are observed in the local carbon deposition patterns when reversing the magnetic field in the experiments. Kinetic impurity-following simulations are performed using the 3D ERO code package with 2D background plasma solutions calculated with the SOLPS5.0 code package. The modelling shows that the measured changes are due to the changes in plasma collisionality, dissociation and ionization rates, and E × B drift of the impurities. These conditions affect the direction and rate of impurity migration inside and out of the divertor, having wider consequences on the global migration of impurities in a divertor tokamak. It is further shown that the migration pathways are largely determined by carbon ions and, hence, relevant for impurities in general. Neutral carbon and hydrocarbons are deposited only in the near vicinity of the injection, where they affect the local re-deposition efficiency. In this limited region, a perturbation of the local plasma conditions by the methane puff appears likely, yielding a significant uncertainty for interpreting the deposition efficiencies. The local deposition is largely influenced by the magnetic presheath electric field, the structure of which is the main uncertainty in the SOLPS5.0-ERO simulations. (paper)

  13. 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)

    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

  14. 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...

  15. Invitation

    CERN Multimedia

    2004-01-01

    « DEUTSCHE MESSE » BY FRANZ SCHUBERT PERFORMED BY THE « WIENER SCHUBERTBUND » On the occasion of the Organization's Fiftieth Anniversary, Mr Hans-Walter Gérard Schober, Honorary Consul-General of Austria in Geneva, is pleased to invite all those working at CERN to a mass at which Franz Schubert's German Mass will be sung by the Vienna Schubert Choral Society. Sunday, 17 October 2004 at 11 a.m., Saint Joseph's Catholic Church, Place des Eaux-Vives, 1207 Geneva (the church has about 900 seats).

  16. 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...

  17. Visible spectroscopy on ASDEX

    International Nuclear Information System (INIS)

    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.)

  18. Invitation

    CERN Multimedia

    2004-01-01

    Monday, 11 October Gala-Concert to celebrate 50 years of CERN Jack Liebeck (violin) and Katya Apekisheva (piano) Works by C. Debussy, S. Prokofiev, and L. van Beethoven CERN, Main Auditorium, 20:00 For CERN staff and their families With the assistance of PPARC (UK) Free tickets available at the CERN Press Office (50-1-048). Maximum four tickets per person. For more information on the performers, see: http://www.jackliebeck.com/CERN50/JL.htm http://www.jackliebeck.com/CERN50/KA.htm The "WIENER SCHUBERTBUND" celebrates CERN's 50th "DEUTSCHE MESSE" By Franz Schubert performed by the "WIENER SCHUBERTBUND" On the occasion of the Organization's Fiftieth Anniversary, Mr Hans-Walter Gérard Schober, Honorary Consul-General of Austria in Geneva, is pleased to invite all those working at CERN to a mass at which Franz Schubert's German Mass will be sung by the Vienna Schubert Choral Society. This renown men's choir, founded in 1863. Eminent composers, including Richard Strauss, Wilhelm Kinzel, a...

  19. UPGRADES

    CERN Multimedia

    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...

  20. 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 ...

  1. 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 ...

  2. 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 ...

  3. Confinement studies on ASDEX

    International Nuclear Information System (INIS)

    This report deals with investigations of plasma confinement carried out on the ASDEX divertor tokamak. It is comprised of two sections: The first section deals with the study of the condinement degradation in auxiliary heated sicharges; in the second section a regime will be described where the severe deterioration of the confinement quality at high heating power is avoided. This regime is called the H-mode because of the high confinement characteristics in contrast to the low confinement L-mode. There is evidence that the L-mode characteristics will not lead to sufficient confinement quality for successful plasma burning. The H-mode was observed for the first time on ASDEX. At present it is considered as the confinement regime with the best prospects for future tokamak operation. But both the study of L- and H-mode confinement physics have increased our understanding on energy transport in tokamaks. (orig./GG)

  4. 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...

  5. B2-Eirene modelling of ASDEX Upgrade

    Science.gov (United States)

    Coster, D. P.; Schneider, R.; Neuhauser, J.; Bosch, H.-S.; Wunderlich, R.; Fuchs, C.; Mast, F.; Kallenbach, A.; Dux, R.; Becker, G.; Braams, B. J.; Reiter, D.; ASDEX Upgrade Team

    1997-02-01

    The extension of the computational region of the coupled fluid plasma, Monte-Carlo neutrals code, B2-Eirene, to the plasma center is discussed. The simulation of completely detached H-mode plasma is presented, as is the modelling of He and Ne compression.

  6. Impurity transport and control in ASDEX Upgrade

    International Nuclear Information System (INIS)

    Impurity transport parameters of Si and Ne have been determined for H-mode and improved H-mode plasmas with and without central wave heating. The diffusion coefficient D is always anomalous in the edge region and about neoclassical in the centre, when central heating powers are low. Sufficient central wave heating increases the central D and leads also to a flattening of the central density profile. Accumulation of W has been studied in improved H-mode discharges. It strongly depends on the density peaking, and can become severe for purely NBI heated discharges with peaked density profiles, while for flat density profiles, which are achieved with sufficient central wave heating, the W concentrations are flat. Extrapolations of the found impurity behaviour were used to guide a case study of particle transport for the ITER-FEAT inductive operation reference scenario. It suggests sufficient anomalous transport and thus negligible impurity accumulation in the inner plasma region. (author)

  7. Divertor efficiency in ASDEX

    Science.gov (United States)

    Engelhardt, W.; Becker, G.; Behringer, K.; Campbell, D.; Eberhagen, A.; Fussmann, G.; Gehre, O.; Gierke, G. V.; Glock, E.; Haas, G.; Huang, M.; Karger, F.; Keilhacker, M.; KlÜber, O.; Kornherr, M.; Lisitano, G.; Mayer, H.-M.; Meisel, D.; Müller, E. R.; Murmann, H.; Niedermeyer, H.; Poschenrieder, W.; Rapp, H.; Schneider, F.; Siller, G.; Steuer, K.-H.; Venus, G.; Vernickel, H.; Wagner, F.

    1982-12-01

    The divertor efficiency in ASDEX is discussed for ohmically heated plasmas. The parameters of the boundary layer both in the torus midplane and the divertor chamber have been measured. The results are reasonably well understood in terms of parallel and perpendicular transport. A high pressure of neutral hydrogen builds up in the divertor chamber and Franck-Condon particles recycle back through the divertor throat. Due to dissociation processes the boundary plasma is effectively cooled before it reaches the neutralizer plates. The shielding property of the boundary layer against impurity influx is comparable to that of a limiter plasma. The transport of iron is numerically simulated for an iron influx produced by sputtering of charge exchange neutrals at the wall. The results are consistent with the measured iron concentration. First results from a comparison of the poloidal divertor with toroidally closed limiters (stainless steel, carbon) are given. Diverted discharges are considerably cleaner and easier to create.

  8. Entropy relaxation of ASDEX plasmas

    International Nuclear Information System (INIS)

    In tokamak discharges with improved ohmic confinement (IOC) in ASDEX a transition is observed from flat density profiles towards more peaked ones, while the normalized temperature profile is preserved. For this behaviour of the radial profiles it is shown that the entropy of the plasma increases during the IOC phase. Hence IOC and entropy relaxation are closely related. If the IOC phase is long enough, one finds stationary plasma states, which are compared with the relaxed state described in theory. (orig.)

  9. Pellet imaging techniques on ASDEX

    International Nuclear Information System (INIS)

    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 DαDβ, and Dγ spectra, obtained with a tangentially viewing scanning mirror/spectrometer with Reticon array readout, are consistent with cloud densities of 2 x 1017cm-3 or higher in the regions of strongest light emission. A spatially resolved array of Dα 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

  10. Investigation of magnetic modes in the ASDEX tokamak

    International Nuclear Information System (INIS)

    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)

  11. ASDEX contributions to the 17th European conference on controlled fusion and plasma heating

    International Nuclear Information System (INIS)

    The 'ASDEX contributions to the 17th European conference on controlled fusion and plasma heating' (Amsterdam, June 25-29, 1990) hold one invited paper (Physics of enhanced confinement with peaked and board density profiles) and 12 chapters containing 44 contributed papers dealing with the following topics: Lower hybrid current drive and heating; Ion cyclotron heating; General confinement studies; Fluctuation studies; Direct measurement of transport coefficients; H-mode studies; Pellet studies; Divertor and SOL-studies; Impurity and impurity transport studies; Density limit studies; MHD studies; Diagnostic development. (orig./AH)

  12. Validation of transport models in ASDEX Upgrade current ramps

    International Nuclear Information System (INIS)

    In order to prepare adequate ramp up and down scenarios for ITER, understanding the physics of transport during the current ramps is essential. The aim of the work was to assess the capability of several transport models to reproduce the experimental data during the current ramps. For this purpose, the calculated temperature profiles from different transport models, i.e. Coppi-Tang, Neo-Alcator, Bohm-Gyrobohm, critical gradient model and H98/2 scaling-based are compared to experimental temperature profiles under different conditions. The strong variation of the experimental electron temperature profiles are partly reproduced by the models. The importance of central and edge radiation will be emphasized, as well as the main transport properties of the models, especially in the case of strong local electron heating (ECRH). To investigate the control capabilities of a Tokamak, particularly with regard to ITER, the impact on global plasma parameters like the internal inductance and the stored energy is also investigated.

  13. Active control of MHD instabilities by ECCD in ASDEX Upgrade

    International Nuclear Information System (INIS)

    The modification of the stability and the behaviour of core MHD with local electron cyclotron current drive (ECCD) is presented. Starting from the inner most resonant surface, the q = 1 surface, the stability and hence the repetition rate and size of sawteeth is controlled with local on/off-axis co/counter- ECCD. The sawteeth themself can serve as a trigger for neoclassical tearing modes (NTM) and therefore the excitation of NTMs can be influenced. Once these NTMs get excited they can be fully stabilised at high βN with co-ECCD at the resonant surface. Detailed experiments on the dependence of the stabilisation on the ECCD deposition width and the total driven current have been shown to improve the stabilisation efficiency both for the (3/2) and the (2/1)-NTM significantly. In the presence of (3/2)-NTMs the impact on the confinement can be reduced by triggering the so-called frequently interrupted regime (FIR-NTM) with current drive in the vicinity of the (4/3) surface leading also to clearer understanding of the FIR-NTM. (author)

  14. OH breaker of ASDEX upgrade: closing switch without ignitrons

    International Nuclear Information System (INIS)

    The OH breaker serves for plasma breakdown. It switches a resistor in a current-carrying inductive circuit. It comprises an opening switch (Q1) and a closing switch (Q3). Both are assessed in detail by measuring the transient currents and voltages of the switching circuit. The closing switch is treated in more detail. It has to carry a dc current of up to 45 kA for several seconds. In this case the switching arc is normally taken by ignitrons and the dc current by vacuum tubes. This paper shows that closing vacuum tubes are capable of working without ignitrons. More than 1,350 Q3 switching actions have confirmed this and support the experimental and theoretical investigations. (orig.)

  15. Viewgraphs presented at the ASDEX/DOE workshop on disruptions in divertor tokamaks

    International Nuclear Information System (INIS)

    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

  16. Fusion reaction product diagnostics in ASDEX

    International Nuclear Information System (INIS)

    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. Periodic multichannel Thomson scattering in ASDEX

    International Nuclear Information System (INIS)

    The optical and electronic design of the Thomson scattering experiment in the ASDEX-Tokamak is described. This Thomson scattering system is employed as a standard diagnostic for the evaluation of electron temperature and density simultaneously at 16 spatial points in ASDEX. The light source is a Nd-YAG laser emitting at 1.06 μm wavelength, which is capable of delivering 60 pulses per second for a period of about 7 sec. This period includes the whole ASDEX plasma discharge. The scattered light is detected by Si-avalanche diodes. Density calibration is carried out by rotational anti-Stokes Raman scattering from molecular hydrogen. The system is capable of measuring densities as low as 5x1012 cm-3 and electron temperatures in the range from 150 eV to 5 keV. The data-processing system and the calculations which lead to the final output of Te/Ne-profiles are discussed. Examples of profile measurements are given showing the possibilities of the system under various plasma conditions. Technical details of the system are described in tables listed in the appendix. (orig.)

  18. Temporally resolved plasma composition measurements by collective Thomson scattering in TEXTOR (invited)

    Energy Technology Data Exchange (ETDEWEB)

    Stejner, M.; Korsholm, S. B.; Nielsen, S. K.; Salewski, M.; Leipold, F.; Michelsen, P. K.; Meo, F. [Association EURATOM-DTU, Department of Physics, Technical University of Denmark, Riso Campus, DK-4000 Roskilde (Denmark); Bindslev, H. [Aarhus University, Faculty of Science and Technology, DK-8000 Aarhus C (Denmark); Moseev, D. [Association EURATOM-DTU, Department of Physics, Technical University of Denmark, Riso Campus, DK-4000 Roskilde (Denmark); FOM Institute DIFFER, Dutch Institute for Fundamental Energy Research, Association EURATOM-FOM, Trilateral Euregio Cluster, Nieuwegein (Netherlands); Buerger, A. [Association EURATOM-FZJ, D-52425 Juelich (Germany); Kantor, M. [FOM Institute DIFFER, Dutch Institute for Fundamental Energy Research, Association EURATOM-FOM, Trilateral Euregio Cluster, Nieuwegein (Netherlands); Ioffe Institute, RAS, Saint Petersburg 194021 (Russian Federation); Baar, M. de [FOM Institute DIFFER, Dutch Institute for Fundamental Energy Research, Association EURATOM-FOM, Trilateral Euregio Cluster, Nieuwegein (Netherlands)

    2012-10-15

    Fusion plasma composition measurements by collective Thomson scattering (CTS) were demonstrated in recent proof-of-principle measurements in TEXTOR [S. B. Korsholm et al., Phys. Rev. Lett. 106, 165004 (2011)]. Such measurements rely on the ability to resolve and interpret ion cyclotron structure in CTS spectra. Here, we extend these techniques to enable temporally resolved plasma composition measurements by CTS in TEXTOR, and we discuss the prospect for such measurements with newly installed hardware upgrades for the CTS system on ASDEX Upgrade.

  19. Laser-blow-off experiments on ASDEX

    International Nuclear Information System (INIS)

    In 1985 laser blow-off system was installed on the ASDEX tokamak and in the following period a number of experiments were performed. The idea of these investigations was to study the impurity behaviour under different plasma conditions. New and unexpected results were obtained: 1. Considerable improvement of the impurity confinement time in OH plasmas near to the density limit, 2. influence on ELMs by impurities, 3. strong dependence of the impurity confinement time on the gradient of the plasma current, and 4. different impurity confinement under various heating conditions. (orig.)

  20. The H-mode of ASDEX

    International Nuclear Information System (INIS)

    This paper is a review of the work on the H-mode done on ASDEX since its discovery in 1982. In detail, it presents (1) the development of the plasma profiles - steep edge gradients and flat bulk profiles, (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, (4) a detailed study of the edge properties including the evidence of 3-dimensional distortions at the edge. The part on confinement encompasses scaling studies and the results of transport analysis. The power threshold of the H-mode is found to depend slightly on the density but hardly on the toroidal field or current. The operational range of the H-mode includes new results on the limiter H-mode of ASDEX and on the development of the H-mode under beam current drive conditions. Several experiments are described which demonstrate the crucial role of the edge electron temperature in the H-mode transition. New material on magnetic and density fluctuation studies at the plasma edge within the edge transport barrier is presented. Finally, the findings on ADSEX are compared with those on other machines and are used to test various H-mode theories. (orig.)

  1. Fueling efficiency of gas puffing in ASDEX

    Science.gov (United States)

    Mayer, H.-M.; Wagner, F.; Becker, G.; Behringer, K.; Campbell, D.; Eberhagen, A.; Engelhardt, W.; Fussman, G.; Gehre, O.; Gierke, G. v.; Glock, E.; Haas, G.; Huang, M.; Karger, F.; Keilhacker, M.; Klüber, O.; Niedermeyer, H.; Poschenrieder, W.; Rapp, H.; Schneider, F.; Siller, G.; Steuer, K.-H.; Venus, G.

    1982-12-01

    The fueling efficiency for gas puffing, i.e. the fraction of the external gas flux that is ionized inside the separatrix, is reduced in divertor discharges since part of it is ionized in the scrape-off layer and pumped off by the divertor. The fueling efficiency is determined by switching-off the gas feed during the stationary phase of a discharge and dividing the time derivative of the total number of particles inside the separatrix by the external gas flux. The determination of this time derivative must take into account profile changes. In ASDEX the fueling efficiency ranges from close to 1.0 for discharges with a stainless steel poloidal limiter and decreases to about 0.2 at high densities ( 6 × 10 13 cm -3 line average) for diverted discharges. These results are compared with estimates of the fueling efficiency which include molecular disintegration, plasma albedo for neutral atoms and imperfect wall reflection.

  2. The ASDEX integrated data analysis system AIDA

    International Nuclear Information System (INIS)

    Since about two years, the ASDEX integrated data analysis system (AIDA), which combines the database (DABA) and the statistical analysis system (SAS), is successfully in operation. Besides a considerable, but meaningful, reduction of the 'raw' shot data, it offers the advantage of carefully selected and precisely defined datasets, which are easily accessible for informative tabular data overviews (DABA), and multi-shot analysis (SAS). Even rather complicated, statistical analyses can be performed efficiently within this system. In this report, we want to summarise AIDA's main features, give some details on its set-up and on the physical models which have been used for the derivation of the processed data. We also give short introduction how to use DABA and SAS. (orig.)

  3. ASDEX contributions to the 19th European conference on controlled fusion and plasma heating (Innsbruck, June 29 to July 3, 1992). - ASDEX contributions to the 10th PSI conference (Monterey, USA, March 30 to April 3, 1992)

    International Nuclear Information System (INIS)

    This paper contains 10 contributions to the following topics: Characteristic features of density fluctuations associated with the L-H-transition in the ASDEX tokamak; change of internal inductance and anisotropy during lower hybrid current drive in ASDEX; a study of the SOL density profile behavior in ASDEX; attempt to model the edge turbulence of a tokamak as a random superposition of eddies; H-mode power threshold in ASDEX; influence of divertor geometry and boronization on elm-free H-mode confinement in ASDEX; ICRF power limitation relation to density limit in ASDEX; reflectometry measurements of the m=1 satellite mode in L- and H-mode plasmas in ASDEX; confiment scaling for the ASDEX L-mode in different divertor configurations; particle and energy transport scalings in the ASDEX scrape-off layer. (orig./MM)

  4. ICRF heating analysis on ASDEX plasmas

    International Nuclear Information System (INIS)

    ICRF (ion cyclotron range of frequencies) waves heating in ASDEX tokamak is analysed. The excitation, propagation and absorption are studied by using a global wave code. This analysis is combined with a Fokker-Planck code, and the generation of fast ions and thermalization of the absorbed power are obtained theoretically. The wave form in the plasma, the loading resistance and reactance of the antenna are calculated for both the minority ion heating and the second harmonic resonance heating. Attention is given to the change of the antenna loading associated with the L/H transition. Optimum conditions for the loading are discussed. In the minority heating case, the tail generation and thermalization are analyzed. Spatial profiles of the tail-ion temperature and the power transferred to the bulk electrons and ions are obtained. Central as well as off-central heating cases are investigated. The ratio of the electron heating power is obtained. Finally, the effect of the reactive electric field is discussed in connection with rf losses and impurity production. (orig.)

  5. Spectroscopy as a major programme in ASDEX - a discussion study

    International Nuclear Information System (INIS)

    This report deals with the objectives and possibilities of a spectroscopy programme in ASDEX and provides some basic information on the relevant processes of atomic physics in tokamaks. The spectroscopic analogies found in observation of astrophysical objects are also briefly treated. In addition, the possibilities for conducting investigations in alternative high-Z ion sources are discussed. A first proposal for an appropriate programme is then formulated. (orig.)

  6. Ion temperature in SOC and IOC discharges in ASDEX

    International Nuclear Information System (INIS)

    Active and passive charge exchange measurements were made to investigate the behaviour of the central ion temperature and the temperature profile for SOC and IOC discharges in ASDEX. Both methods show an increase in the central ion temperature during transition from SOC to IOC. Both methods also show a wider temperature profile for ions than for electrons. Peaking of the ion temperature profile during IOC cannot be definitely concluded from the measurements. (author) 7 refs., 4 figs

  7. A data bank of disruptive discharges in ASDEX

    International Nuclear Information System (INIS)

    The compilation of data banks relating to plasma disruptions is important for the design of next-step devices and tokamak reactors, as a means of establishing safe operation regimes and assessing the residual risk from such events. ASDEX has an operational history of 33509 plasma shots covering an exceptionally wide range of machine conditions: Divertor/limiter configurations; Ohmic, NBI, ICRH and LH heating; carbonization, boronization wall-conditioning, gas-puff and pellet refuelling. We have compiled a data base of the Disruptive Operationl Regimes in ASDEX (DORA), which contains the relevant information for all ASDEX-discharges and is available on tape and readable by different data bank systems for further evaluation. We first describe the criteria applied to recognize and classify disruptions and the information about them stored in the file. In a second part we use the DORA file for some sample applications of physical or engineering interest. In an appendix we give the data and format information necessary to read the DORA file. (orig.)

  8. Subsidiary Upgrading?

    DEFF Research Database (Denmark)

    Gammelgaard, Jens; Dörrenbächer, Christoph

    2004-01-01

    AbstractThis study reports the results of interviews with 65 managers in 11 Germanheadquarters and in their 13 Hungarian subsidiaries. We focused on the role of thesubsidiary with regard to market, product and value-adding mandates. Further, weinvestigated whether the Hungarian subsidiaries had e......, ethnocentric behaviours emanating from the headquarters should be includedin future upgrading analyses....

  9. Subsidiary Upgrading?

    OpenAIRE

    Dörrenbächer, Christoph; Gammelgård, Jens

    2004-01-01

    Abstract This study reports the results of interviews with 65 managers in 11 German headquarters and in their 13 Hungarian subsidiaries. We focused on the role of the subsidiary with regard to market, product and value-adding mandates. Further, we investigated whether the Hungarian subsidiaries had experienced an upgrade of their role during the first 10 years of transition. The host country economy was supportive to role development, but inadequate subsidiary capabilities a...

  10. Design of magnetic probes for MHD measurements in ASDEX tokamak

    International Nuclear Information System (INIS)

    The design of magnetic probes (Mirnov coils) is described in this report. These probes are used in ASDEX to investigate MHD modes and measure the plasma displacement together with magnetic flux loops. Concerning the high temperature rise during a plasma shot proper material for the coil form of the magnetic probes and the suitable wire and cable in the high vacuum chamber in conjunction with special geometrical construction have been selected. The electrical circuit updated to operate in a high noise environment is shown and first MHD mode signals demonstrate the effeciency of the system. (orig.)

  11. ASDEX upgrade results - publications and conference contributions. Period 10/93 to 7/94

    International Nuclear Information System (INIS)

    The report contains the papers of IPP members contributed to the conferences as follows: 1) 4th H-Mode Workshop, NAKA-JAERI, Japan Nov. 1993; 2) 11th Topical Meeting on the Technology of Fusion Energy, New Orleans, June 1994; 3) 11th International Conference on Plasma Surface Interactions in Controlled Fusion Devices, Mito-shi, Japan, May 23-27, 1994; 4) 21th EPS Conference on Controlled Fusion and Plasma Physics, Montpellier, June 27 to July 1, 1994. (HP)

  12. Ball-Pen Probe Measurements in L-Mode and H-Mode on ASDEX Upgrade

    Czech Academy of Sciences Publication Activity Database

    Adámek, Jiří; Horáček, Jan; Müller, H. W.; Rohde, V.; Ionita, C.; Schrittwieser, R.; Mehlmann, F.; Kurzan, B.; Stöckel, Jan; Dejarnac, Renaud; Weinzettl, Vladimír; Seidl, Jakub; Peterka, M.

    2010-01-01

    Roč. 50, č. 9 (2010), s. 854-859. ISSN 0863-1042. [International Workshop on Electric Probes in Magnetized Plasmas/8th./. Innsbruck, 21.09.2009-24.09.2009] R&D Projects: GA AV ČR KJB100430901; GA ČR GA202/09/1467 Institutional research plan: CEZ:AV0Z20430508 Keywords : Tokamak * ball-pen probe * electron temperature * L-mode * H-mode * ELMs Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 1.006, year: 2010 http://onlinelibrary.wiley.com/doi/10.1002/ctpp.201010145/pdf

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

    DEFF Research Database (Denmark)

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

    2008-01-01

    gyrotron Odissey-1 is currently being equipped with a broadband chemical vapour deposition (CVD) diamond Brewster output window and will become a step-tunable gyrotron with the additional frequencies 117 and 127 GHz. A tunable double-disc CVD-diamond window will be mounted at the torus. The system includes...

  14. Automatic setting of machine control with physics operation parameters at ASDEX Upgrade

    International Nuclear Information System (INIS)

    Performing plasma fusion experiments in a tokamak relies on close cooperation between discharge control (DCS) and machine control (MCS) systems, where the DCS's task is generating and handling the plasma, and the MCS is responsible for providing and configuring the necessary actuators. With a reduced number of experiment cycles per day, in consequence of long pulses or ambitious discharge scenarios, optimal utilization of resources as well as avoiding mismatches between the MCS' and DCS' configurations becomes increasingly important. Setting up the MCS for discharges currently relies on informal communication and requires careful attention of operators and session leaders. To enforce correspondence between MCS and DCS parametrizations, an automatic mediator agent formalizes the pre-shot configuration procedure. Functionality of the mediator and protocols for embedding into the existing system are discussed

  15. Assessment of compatibility of ICRF antenna operation with full W wall in ASDEX Upgrade

    Czech Academy of Sciences Publication Activity Database

    Bobkov, Vl.V.; Braun, F.; Dux, R.; Herrmann, A.; Giannone, L.; Kallenbach, A.; Křivská, Alena; Müller, H.W.; Neu, R.; Noterdaeme, J.-M.; Pütterich, T.; Rohde, V.; Schweinzer, J.; Sips, A.; Zammuto, I.

    2010-01-01

    Roč. 50, č. 3 (2010), 035004-035004. ISSN 0029-5515. [Workshop on Stochasticity in Fusion Plasmas/4./. Julich, 02.03.2009-04.03.2009] Institutional support: RVO:61389021 Keywords : tokamak * ICRF Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 3.303, year: 2010 http://iopscience.iop.org/0029-5515/50/3/035004/pdf/0029-5515_50_3_035004.pdf

  16. Interpretation of D_alpha Imaging Diagnostics Data on the ASDEX Upgrade Tokamak

    OpenAIRE

    Harhausen, Jens

    2009-01-01

    The Tokamak configuration is a promising concept for magnetic confinement fusion. Cross-field transport in the plasma core leads to a plasma flux across the separatrix into the scrape-off layer, where it is guided along field lines towards the divertor targets. A return flux of neutral particles after plasma-wall interaction is directed towards the plasma chamber. Each discharge scenario is accompanied by a characteristic recycling pattern. The dominant mechanisms of neutralplasma...

  17. ASDEX upgrade results. Publications and conference contributions. Period 6/92 to 9/93

    International Nuclear Information System (INIS)

    The report contains the papers of IPP members contributed to the conferences as follows: 1. 29th EPS Conference on Controlled Fusion and Plasma Physics, Innsbruck, June 19-July 3, 1992; 2. 14th International Conference on Plasma Physics and Controlled Nuclear Fusion Research, Wuerzburg, Sept. 30-Oct.7, 1992; 3. 10th APS Conference on Radio Frequency Power to Plasmas, Boston, 1993, 4. 20th EPS Conference on Controlled Fusion and Plasma Physics, Lisbon, July 26-30, 1993; 4. 18th International Conference on Infrared and Millimeter Waves, University of Essex, Sept. 6-10, 1993. (HP)

  18. Experimental tests of confinement scale invariance on JET, DIIID, ASDEX Upgrade and CMOD

    International Nuclear Information System (INIS)

    An international collaboration between JET, DIIID, AUG and CMOD has resulted in four sets of Tokamak discharges which are approximately identical as regards a set of dimensionless plasma variables. The data demonstrates some measure of scale invariance of local and global confinement but a more accurate matching of scaled density, power etc. is required to make firmer conclusions. (author)

  19. Fast ion dynamics in ASDEX upgrade and TEXTOR measured by collective Thomson scattering

    Energy Technology Data Exchange (ETDEWEB)

    Moseev, D.

    2011-11-15

    Fast ions are an essential ingredient in burning nuclear fusion plasmas: they are responsible for heating the bulk plasma, carry a significant amount of plasma current and moreover interact with various magnetohydrodynamic (MHD) instabilities. The collective Thomson scattering (CTS) diagnostic is sensitive to the projection of fast ion velocity distribution function. This thesis is mainly devoted to investigations of fast ion physics in tokamak plasmas by means of CTS. (Author)

  20. On the asymmetries of ELM divertor power deposition in JET and ASDEX Upgrade

    DEFF Research Database (Denmark)

    Eich, T.; Kallenbach, A.; Fundamenski, W.;

    2009-01-01

    An analytical expression was derived for describing the divertor target power during ELMs based on the model discussed in [W. Fundamenski, R.A. Pitts, Plasma Phys. Control. Fus. 48 (2006) 109] where the power load arises from a Maxwellian distribution of particles released into the SOL region. The...

  1. Fast ion dynamics in ASDEX upgrade and TEXTOR measured by collective Thomson scattering

    International Nuclear Information System (INIS)

    Fast ions are an essential ingredient in burning nuclear fusion plasmas: they are responsible for heating the bulk plasma, carry a significant amount of plasma current and moreover interact with various magnetohydrodynamic (MHD) instabilities. The collective Thomson scattering (CTS) diagnostic is sensitive to the projection of fast ion velocity distribution function. This thesis is mainly devoted to investigations of fast ion physics in tokamak plasmas by means of CTS. (Author)

  2. Real-time protection of in-vessel components in ASDEX Upgrade

    International Nuclear Information System (INIS)

    A video real time safety system (VRT) for protection of in-vessel components was fully implemented in the machine control system (CODAC) from the 2007 experimental campaign on. The VRT is based on video cameras in contrast to infrared systems. The visible wavelength range has a smaller measurement range but is a factor 5-10 less sensitive against changes of the transmission of the optical system and the target emissivity compared to infrared systems. Up to 12 analog video channels with multiple regions of interest (ROI) are processed and monitored on each video stream. At present two safety algorithms, to detect the fraction of overheating in a ROI and hot spot detection, respectively, are implemented. The integral algorithm is preferentially used for probe or limiter protection, the hot spot algorithm for divertor protection. The VRT system is realized with ReadHawk real time operating system on a multi core Linux computer.

  3. Accuracy of Automatic Density Profile Measurements with FM-CW Reflectometry on ASDEX Upgrade

    Science.gov (United States)

    Santos, Jorge; Emilia Manso, Maria; Nunes, Fernando; Varela, Paulo; ASDEX Upgrade Team

    2000-10-01

    Reflectometry is a radar technique that uses robust and compact equipment (requiring reduced access to the machine), to measure the density profile in fusion plasmas with both high spatial and temporal resolutions. In addition it can provide information about plasma turbulence, MHD activity, ELMs, Marfes, TAE modes, etc. Due to the above advantages, reflectometry is foreseen to play a major role on next fusion devices, namely it has been proposed for plasma position control on ITER-FEAT, based on a set of poloidal distributed edge density profile measurements. This is a new challenge for reflectometry that has to be proven on present fusion experiments.

  4. Fast Ion Dynamics in ASDEX Upgrade and TEXTOR Measured by Collective Thomson Scattering

    DEFF Research Database (Denmark)

    Moseev, Dmitry

    Fast ions are an essential ingredient in burning nuclear fusion plasmas: they are responsible for heating the bulk plasma, carry a significant amount of plasma current and moreover interact with various magnetohydrodynamic (MHD) instabilities. The collective Thomson scattering (CTS) diagnostic is...

  5. Collective Thomson scattering measurements of fast-ion transport due to sawtooth crashes in ASDEX Upgrade

    DEFF Research Database (Denmark)

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

    2016-01-01

    Sawtooth instabilities can modify heating and current-drive profiles and potentially increase fast-ion losses. Understanding how sawteeth redistribute fast ions as a function of sawtooth parameters and of fast-ion energy and pitch is hence a subject of particular interest for future fusion devices...

  6. High frequency magnetic fluctuations correlated with the inter-ELM pedestal evolution in ASDEX Upgrade

    Science.gov (United States)

    Laggner, F. M.; Wolfrum, E.; Cavedon, M.; Mink, F.; Viezzer, E.; Dunne, M. G.; Manz, P.; Doerk, H.; Birkenmeier, G.; Fischer, R.; Fietz, S.; Maraschek, M.; Willensdorfer, M.; Aumayr, F.; the EUROfusion MST1 Team; the ASDEX Upgrade Team

    2016-06-01

    In order to understand the mechanisms that determine the structure of the high confinement mode (H-mode) pedestal, the evolution of the plasma edge electron density and temperature profiles between edge localised modes (ELMs) is investigated. The onset of radial magnetic fluctuations with frequencies above 200 kHz is found to correlate with the stagnation of the electron temperature pedestal gradient. During the presence of these magnetic fluctuations the gradients of the edge electron density and temperature are clamped and stable against the ELM onset. The detected magnetic fluctuation frequency is analysed for a variety of plasma discharges with different electron pressure pedestals. It is shown that the magnetic fluctuation frequency scales with the neoclassically estimated \\text{E} × \\text{B} velocity at the plasma edge. This points to a location of the underlying instability in the gradient region. Furthermore, the magnetic signature of these fluctuations indicates a global mode structure with toroidal mode numbers of approximately 10. The fluctuations are also observed on the high field side with significant amplitude, indicating a mode structure that is symmetric on the low field side and high field side. The associated fluctuations in the current on the high field side might be attributed to either a strong peeling part or the presence of non-adiabatic electron response.

  7. Coal upgrading

    Energy Technology Data Exchange (ETDEWEB)

    Nunes, S. [IEA Clean Coal Centre, London (United Kingdom)

    2009-10-15

    This report examines current technologies and those likely to be used to produce cleaner coal and coal products, principally for use in power generation and metallurgical applications. Consideration is also given to coal production in the leading coal producing countries, both with developed and developing industries. A range of technologies are considered. These include the coal-based liquid fuel called coal water mixture (CWM) that may compete with diesel, the production of ultra-clean coal (UCC) and coal liquefaction which competes with oil and its products. Technologies for upgrading coal are considered, especially for low rank coals (LRC), since these have the potential to fill the gap generated by the increasing demand for coal that cannot be met by higher quality coals. Potential advantages and downsides of coal upgrading are outlined. Taking into account the environmental benefits of reduced pollution achieved through cleaner coal and reduced transport costs, as well as other positive aspects such as a predictable product leading to better boiler design, the advantages appear to be significant. The drying of low rank coals improves the energy productively released during combustion and may also be used as an adjunct or as part of other coal processing procedures. Coal washing technologies vary in different countries and the implications of this are outlined. Dry separation technologies, such as dry jigging and electrostatic separation, are also described. The demonstration of new technologies is key to their further development and demonstrations of various clean coal technologies are considered. A number of approaches to briquetting and pelletising are available and their use varies from country to country. Finally, developments in upgrading low rank coals are described in the leading coal producing countries. This is an area that is developing rapidly and in which there are significant corporate and state players. 81 refs., 32 figs., 3 tabs.

  8. An equipment protection and safety system for the ASDEX tokamak

    International Nuclear Information System (INIS)

    Our compromise between safety requirements and costs is a hybrid of relay, solid-state and computer-controlled protection systems used for ASDEX. The toroidal field coils, ohmic heating coils, vertical field coils, divertor coils, radial field coils, stainless-steel vacuum vessel and structure are protected by measuring the water flow (131 channels), temperature (142 channels), mechanical displacements (141 channels), voltage symmetry (28 channels), current symmetry (6 channels), weight of the vessel (8 channels) and the overvoltage. To detect flow, temperature, displacement, voltage, current and weight, we use the following devices: Venturi tubes (self-made), RTD thermoresistors (Pt-100), linear potentiometers (1 kΩ), voltage dividers (self-made), Rogowski coils (self-made) and straing gauges. (orig.)

  9. A new time constant in ASDEX determining the OH confinement

    International Nuclear Information System (INIS)

    The transient response of the stored energy to density variations is studied in ASDEX ohmic discharges. It is found that the phase delay between the stored energy to the density variations is much smaller than the energy confinement time, τE, in the density regime where τE scales like the Alcator scaling (anti ne c). The phase delay increases dramatically in the high density regime where τE saturates with density (anti ne > anti nc). The phase delay associated with density increase by pellet injection is small for operation at both high and low density. The value observed with pellet injection is as short as that seen in the low density gas puffing regime. (orig./GG)

  10. Inviting Positive Classroom Discipline.

    Science.gov (United States)

    Purkey, William Watson; Strahan, David B.

    Invitational theory addresses the total educational environment and culture of the classroom and school, focusing on the people, places, policies, programs, and processes that constitute any school culture. Invitational teaching is a process for communicating caring and appropriate messages to nurture the realization of student potential as well…

  11. An optical scanning system for spectroscopic impurity flux investigations inside the ASDEX tokamak

    International Nuclear Information System (INIS)

    A scanning mirror system was developed to resolve impurity flux sources spatially across about 2/3 of the ASDEX surface by using visible spectroscopy. A totally computer-controlled layout allows wide-range spatial scanning during a discharge. Spectra over a range of ∝ 150 A are recorded with an integration time down to 20 ms. The versatility of this new system is illustrated by means of first observations of ASDEX discharges with additional heating (NI, LH, ICRH) and modulated gas puffing experiments. (orig.)

  12. Investigation of limiter recycling in the divertor tokamak ASDEX

    International Nuclear Information System (INIS)

    A divertor experiment like the ASDEX tokamak is especially suited for studying ion recycling at a material limiter, because the plasma can alternatively be limited by a magnetic limiter (separatrix) or by a material limiter. The role of the material limiter in ion recycling is documented by observing the increase in charge exchange flux emitted at the limiter position, and the decrease in external gas input necessary to keep the plasma line density invariant, when the material limiter is moved to the plasma. Ion recycling occurs predominantly at the outside section of a ring limiter. The limiter material saturates shortly after the start of the discharge. About 60% of the total recycling occurs at the limiter, which is nearly 100% of the ion recycling. The remaining 40% of the total recycling is carried by charge exchange neutrals. Due to saturation, the recycling coefficient at the limiter is 1; the recycling coefficient of the charge exchange neutrals at the wall is approximately 0.5 giving rise to a total recycling coefficient of limiter discharges of 0.8-0.9. It is observed that the plasma resistivity increases when the material limiter is moved toward the separatrix. The increase in Zsub(eff) can tentatively be explained by proton sputtering. (orig.)

  13. Statistical analyses of local transport coefficients in ohmic ASDEX discharges

    International Nuclear Information System (INIS)

    Tokamak energy transport is still an unsolved problem. Many theoretical models have been developed, which try to explain the anomalous high energy-transport coefficients. Up to now these models have been applied to global plasma parameters. A comparison of transport coefficients with global confinement time is only conclusive if the transport is dominated by one process across the plasma diameter. This, however, is not the case in most of the Ohmic confinement regimes, where at least three different transport mechanisms play an important role. Sawtooth activity leads to an increase in energy transport in the plasma centre. In the intermediate region turbulent transport is expected. Candidates here are drift waves and resistive fluid turbulences. At the edge, ballooning modes or rippling modes could dominate the transport. For the intermediate region, one can deduce theoretical scaling laws for τE from turbulent theories. Predicted scalings reproduce the experimentally found density dependence of τE in the linear Ohmic confinement regime (LOC) and the saturated regime (SOC), but they do not show the correct dependence on the isotope mass. The relevance of these transport theories can only be tested in comparing them to experimental local transport coefficients. To this purpose we have performed transport calculations on more than a hundred Ohmic ASDEX discharges. By Principal Component Analysis we determine the dimensionless components which dominate the transport coefficients and we compare the results to the predictions of various theories. (orig.)

  14. The multiple facets of ohmic confinement in ASDEX

    International Nuclear Information System (INIS)

    The scaling of the energy confinement time with plasma density and current has been investigated for Ohmically heated tokamak discharges in ASDEX. The linear dependence τE ∝ anti ne is maintained in the high density Improved Ohmic Confinement (IOC) regime with peaked density profiles. The peaking of the radial density profile can be brought about by reducing the net power flow through the plasma surface thereby effecting a reduction of the edge density. Tailoring of the radiation profile with the addition of low-Z impurities e.g. neon gives access to the IOC regime under conditions where otherwise the degraded Saturated Ohmic Confinement (SOC) behavior prevails. The energy confinement time increases with current and decreases with heating poweer also in Ohmic discharges as shown by a statistical analysis. But with the intrinsic coupling between power and current, both relationships cancel and τE becomes independent of POH and Ip. The two most prominent features of Ohmic confinement can therefore be explained on the basis of simple physical models. (orig.)

  15. Stability investigations of the ASDEX feedback system with filters for reducing thyristor noise

    International Nuclear Information System (INIS)

    A computer program for analysing the absolute and relative stabilities of any complex system by the root-locus method was developed. It is used to reanalyse the present horizontal position feed-back control in the ASDEX tokamak and to select the optimum parameters for this system with RCL filters for reducing thyristor noise. (orig.)

  16. ASDEX papers at the 13th European conference on controlled fusion and plasma physics

    International Nuclear Information System (INIS)

    This report provides 29 ASDEX papers concerning pellet refuelling, confinement, high-beta plasma and MHD-equilibrium, heating by ICR, lower hybrid and current-drive, impurity studies and plasma diagnostics. All of these papers have been indexed separately. (GG)

  17. The D0 Upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Abachi, S.; D0 Collaboration

    1995-07-01

    In this paper we describe the approved DO Upgrade detector, and its physics capabilities. The DO Upgrade is under construction and will run during the next Fermilab collider running period in early 1999 (Run II). The upgrade is designed to work at the higher luminosities and shorter bunch spacings expected during this run. The major elements of t he upgrade are: a new tracking system with a silicon tracker, scintillating fiber tracker, a 2T solenoid, and a central preshower detector; new calorimeter electronics; new muon trigger and tracking detectors with new muon system electronics; a forward preshower detector; new trigger electronics and DAQ improvements to handle the higher rates.

  18. An Invitation to Theory

    Institute of Scientific and Technical Information of China (English)

    梁景宏

    2010-01-01

    In this essay, I wish to invite young scholars to learn, use, and contribute to accounting theory. In this invitation, I argue theory has lineage, is important and can be fun. Its lineage comes from the post-WWII scientific revolution in management education and research. Theory is important because it is the successful interaction between theory and empirical work that ultimately advances an academic discipline. Theory can be fun because when done well, learning, using and contributing to theory can be an enjoyable activity for all scholars, either as consumers or as producers of theory.

  19. You are invited to submit…

    OpenAIRE

    Moher, David; Srivastava, Anubhav

    2015-01-01

    The academic community is under great pressure to publish. This pressure is compounded by high rejection rates at many journals. A more recent trend is for some journals to send invitations directly to researchers inviting them to submit a manuscript to their journals. Many researchers find these invitations annoying and unsure how best to respond to them. We collected electronic invitations to submit a manuscript to a journal between April 1, 2014, and March 31, 2015. We analyzed their conte...

  20. Upgrading uncompetitive products economically

    DEFF Research Database (Denmark)

    Lu, Hua; Jensen, Christian Søndergaard

    2012-01-01

    The skyline of a multidimensional point set consists of the points that are not dominated by other points. In a scenario where product features are represented by multidimensional points, the skyline points may be viewed as representing competitive products. A product provider may wish to upgrade...... the k products in T that can be upgraded to not be dominated by any products in P at the lowest cost. This problem is non-trivial due to not only the large data set sizes, but also to the many possibilities for upgrading a product. We identify and provide solutions for the different options for...... upgrading an uncompetitive product, and combine the solutions into a single solution. We also propose a spatial join-based solution that assumes P and T are indexed by an R-tree. Given a set of products in the same R-tree node, we derive three lower bounds on their upgrading costs. These bounds are employed...

  1. NSLS control system upgrade

    International Nuclear Information System (INIS)

    The NSLS consists of two storage rings, a booster and a linac. A major upgrade of the control system (installed in 1978) was undertaken and has been completed. The computer architecture is being changed from a three level star-network to a two level distributed system. The microprocessor subsystem, host computer and workstations, communication link and the main software components are being upgraded or replaced. Since the NSLS rings operate twenty four hours a day a year with minimum maintenance time, the key requirement during the upgrade phase is a non-disruptive transition with minimum downtime. Concurrent with the upgrade, some immediate improvements were required. This paper describes the various components of the upgraded system and outlines the future plans

  2. An operational test of a time-of-flight analyser at the ASDEX tokamak

    International Nuclear Information System (INIS)

    The performance of a time-of-flight energy analyser, used for the investigation of the slowing-down spectrum of the heating beams at the ASDEX tokamak, is described. The time-of-flight analyser has a short flight path (15 cm). Its energy resolution amounts to a few per cent. The analyser was equipped with a preselecting, achromatic magnet system to separate the fast neutrals from thermal plasma particles and light

  3. Upgrading during difficult times

    International Nuclear Information System (INIS)

    The Co-op Upgrader is part of an integrated refinery and upgrader complex in Regina, Saskatchewan. The upgrader processes 50,000 bbl/d heavy sour crude oil, mostly Fosterton and dilute Lloydminster crude, via hydrogen addition and carbon rejection, desulfurization, demetallization, and denitrification to yield a synthetic crude blend. The synthetic crude is refined to produce gasoline and diesel fuel. Byproducts from the integrated operation include 100,000 tonnes/y of petroleum coke, 65,000 tonnes/y of sulfur, propane, butane, fuel oil, and metals (Ni and V) in the form of spent catalysts. Recent operational and economic challenges faced by the upgrader are reviewed. Technical challenges include operating the upgrader's high-temperature high-pressure heavy oil hydrotreating unit and distillate hydrogenation unit, removal and replacement of the desulfurization catalyst, waste management, and producing coke of sufficient quality. Economic challenges include the shrinking differential between light and heavy oil, higher prices for natural gas (the main raw material for hydrogen production for upgrading), seasonal changes in product specifications, and lower prices for sulfur and metal byproducts. The upgrader is also affected by interest rates since borrowing costs are the single largest expenditure after crude oil purchases. 4 figs

  4. You are invited to submit….

    Science.gov (United States)

    Moher, David; Srivastava, Anubhav

    2015-01-01

    The academic community is under great pressure to publish. This pressure is compounded by high rejection rates at many journals. A more recent trend is for some journals to send invitations directly to researchers inviting them to submit a manuscript to their journals. Many researchers find these invitations annoying and unsure how best to respond to them. We collected electronic invitations to submit a manuscript to a journal between April 1, 2014, and March 31, 2015. We analyzed their content and cross-tabulated them against journals listed in Beall's list of potential predatory journals. During this time period, 311 invitations were received for 204 journals, the majority of which were in Beall's list (n = 244; 79%). The invitations came throughout the calendar year and some journals sent up to six invitations. The majority of journals claimed to provide peer review (n = 179; 57.6%) although no mention was made of expedited review process. Similarly, more than half of the journals claimed to be open access (n = 186; 59.8%). The majority of invitations included an unsubscribe link (n = 187; 60.1%). About half of the invitations came from biomedical journals (n = 179). We discuss strategies researchers and institutions can consider to reduce the number of invitations received and strategies to handle those invitations that make it to the recipients' inbox, thus helping to maintain the credibility and reputation of researchers and institutions. PMID:26239633

  5. Trajectory for Industrial Upgrade

    Institute of Scientific and Technical Information of China (English)

    LIU YUNYUN

    2010-01-01

    @@ The Ministry of Industry and Information Technology (MIIT) ordered the closure of outdated production lines in 18 industries as part of the country's plan to upgrade its industrial structure and move up the value chain.

  6. Trajectory for Industrial Upgrade

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The Ministry of Industry and Information Technology(MIIT) ordered the closure of outdated production lines in 18 industries as part of the country’s plan to upgrade its industrial structure and move up the

  7. 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.

  8. LEP is upgraded

    CERN Multimedia

    1995-01-01

    A superconducting radio-frequency cavity is installed on the Large Electron-Positron (LEP) collider. This upgrade, known as LEP-2, allowed the accelerator to reach new, higher energies and so investigate new areas of physics.

  9. Effect of resonant magnetic perturbations on low collisionality discharges in MAST and a comparison with ASDEX Upgrade

    Czech Academy of Sciences Publication Activity Database

    Kirk, A.; Suttrop, W.; Chapman, I.T.; Liu, Y.; Scannell, R.; Thornton, A.J.; Barrera Orte, L.; Cahyna, Pavel; Eich, T.; Fischer, R.; Fuchs, C.; Ham, C.; Harrison, J.R.; Jakubowski, M.W.; Kurzan, B.; Pamela, S.; Peterka, Matěj; Ryan, D.; Saarelma, S.; Sieglin, B.; Valovic, M.; Willensdorfer, M.

    2015-01-01

    Roč. 55, č. 4 (2015), 043011-043011. ISSN 0029-5515 Institutional support: RVO:61389021 Keywords : ELM mitigation * ELM energy loss * MAST * AUG Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 3.062, year: 2014 http://iopscience.iop.org/0029-5515/55/4/043011

  10. Radial profiles of the electron temperature on COMPASS and ASDEX Upgrade from ball-pen probe and Thomson scattering diagnostic.

    Czech Academy of Sciences Publication Activity Database

    Adámek, Jiří; Müller, H.W.; Horáček, Jan; Schrittwieser, R.; Vondráček, Petr; Kurzan, B.; Bílková, Petra; Böhm, Petr; Aftanas, Milan; Pánek, Radomír

    Vol. 38F. Mulhouse : European Physical Society, 2014 - (Ratynskaia, S.; Mantica, P.; Benuzzi-Mounaix, A.; Dilecce, G.; Bingham, R.; Hirsch, M.; Kemnitz, B.; Klinger, T.), P2.011-P2.011 ISBN 2-914771-90-8. - (Europhysics Conference Abstracts (ECA)). [EPS Conference on Plasma Physics/41./. Berlin (DE), 23.06.2014-27.06.2014] R&D Projects: GA ČR(CZ) GAP205/12/2327; GA MŠk(CZ) LM2011021 Institutional support: RVO:61389021 Keywords : ball-pen probe * electron temperature * tokamak * Thomson scattering Subject RIV: BL - Plasma and Gas Discharge Physics http://ocs.ciemat.es/EPS2014PAP/pdf/P2.011.pdf

  11. Effect of resonant magnetic perturbations on low collisionality discharges in MAST and a comparison with ASDEX Upgrade

    CERN Document Server

    Kirk, A; Liu, Yueqiang; Chapman, I T; Cahyna, P; Eich, T; Fuchs, C; Ham, C; Harrison, J R; Jakubowski, M W; Pamela, S; Peterka, M; Ryan, D; Saarelma, S; Scannell, R; Thornton, A J; Valovic, M; Sieglin, B; Orte, L Barrera; Willensdorfer, M; Kurzan, B; Fischer, R; Upgrade, ASDEX

    2014-01-01

    Sustained ELM mitigation has been achieved on MAST and AUG using RMPs with a range of toroidal mode numbers over a wide region of low to medium collisionality discharges. The ELM energy loss and peak heat loads at the divertor targets have been reduced. The ELM mitigation phase is typically associated with a drop in plasma density and overall stored energy. In one particular scenario on MAST, by carefully adjusting the fuelling it has been possible to counteract the drop in density and to produce plasmas with mitigated ELMs, reduced peak divertor heat flux and with minimal degradation in pedestal height and confined energy. While the applied resonant magnetic perturbation field can be a good indicator for the onset of ELM mitigation on MAST and AUG there are some cases where this is not the case and which clearly emphasise the need to take into account the plasma response to the applied perturbations. The plasma response calculations show that the increase in ELM frequency is correlated with the size of the e...

  12. Towards Fast Measurement of the Electron Temperature in the SOL of ASDEX Upgrade Using Swept Langmuir Probes

    Czech Academy of Sciences Publication Activity Database

    Müller, H. W.; Adámek, Jiří; Horáček, Jan; Ionita, C.; Mehlmann, F.; Rohde, V.; Schrittwieser, R.

    2010-01-01

    Roč. 50, č. 9 (2010), s. 847-853. ISSN 0863-1042. [International Workshop on Electric Probes in Magnetized Plasmas/8th./. Innsbruck, 21.09.2009-24.09.2009] R&D Projects: GA AV ČR KJB100430901; GA ČR GA202/09/1467 Institutional research plan: CEZ:AV0Z20430508 Keywords : Tokamak * Langmuir probe * swept probe * ball-pen probe * fast temperature measurement * ELM Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 1.006, year: 2010 http://onlinelibrary.wiley.com/doi/10.1002/ctpp.201010144/pdf

  13. Direct plasma potential measurements by ball-pen probe and self-emitting langmuir probe on COMPASS and ASDEX upgrade

    Czech Academy of Sciences Publication Activity Database

    Adámek, Jiří; Horáček, Jan; Seidl, Jakub; Müller, H.W.; Schrittwieser, R.; Mehlmann, F.; Vondráček, Petr; Pták, Svatopluk

    2014-01-01

    Roč. 54, č. 3 (2014), s. 279-284. ISSN 0863-1042 R&D Projects: GA ČR(CZ) GAP205/12/2327 Institutional support: RVO:61389021 ; RVO:61388998 Keywords : Tokamak * ball-pen probe * emissive probe * L-mode * plasma potential Subject RIV: BL - Plasma and Gas Discharge Physics; BL - Plasma and Gas Discharge Physics (UT-L) Impact factor: 0.838, year: 2014

  14. Theoretical description of heavy impurity transport and its application to the modelling of tungsten in JET and ASDEX upgrade

    Czech Academy of Sciences Publication Activity Database

    Casson, F.J.; Angioni, C.; Belli, E.A.; Bilato, R.; Mantica, P.; Odstrčil, T.; Pütterich, T.; Valisa, M.; Garzotti, L.; Giroud, C.; Hobirk, J.; Maggi, C.F.; Mlynář, Jan; Reinke, M.L.

    2015-01-01

    Roč. 57, č. 1 (2015), 014031-014031. ISSN 0741-3335 Institutional support: RVO:61389021 Keywords : tokamak * impurity * transport * neoclassical * validation * modelling * tungsten Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 2.186, year: 2014 http://iopscience.iop.org/article/10.1088/0741-3335/57/1/014031/ meta

  15. Direct observation of current in type-I edge-localized-mode filaments on the ASDEX upgrade tokamak

    DEFF Research Database (Denmark)

    Vianello, N.; Zuin, M.; Cavazzana, R.;

    2011-01-01

    Magnetically confined plasmas in the high confinement regime are regularly subjected to relaxation oscillations, termed edge localized modes (ELMs), leading to large transport events. Present ELM theories rely on a combined effect of edge current and the edge pressure gradients which result...... in intermediate mode number (n≅10-15) structures (filaments) localized in the perpendicular plane and extended along the field lines. By detailed localized measurements of the magnetic field perturbation associated to type-I ELM filaments, it is shown that these filaments carry a substantial current. © 2011...

  16. Understanding of the density profile shape, electron heat transport and internal transport barriers observed in ASDEX Upgrade

    International Nuclear Information System (INIS)

    In this paper several transport phenomena are described and explained through the properties of micro-instabilities. Linear and quasi-linear theory are used, which give a reasonable qualitative description of the relatively weak turbulent state of the plasma core. The paper deals with the following phenomena: density peaking, electron heat transport, density pump-out, reactor density profiles, stabilisation of the ion temperature gradient mode in transport barriers. (author)

  17. Quantification of the impact of large and small-scale instabilities on the fast-ion confinement in ASDEX Upgrade

    DEFF Research Database (Denmark)

    Geiger, B.; Weiland, M.; Mlynek, A.;

    2015-01-01

    with the theoretical predictions based on the Kadomtsev model. Between the sawtooth crashes, the fishbone modes are excited which, however, do not cause measurable changes in the global fast-ion population. During experiments with on- and off-axis NBI and without strong magnetohydrodynamic (MHD) modes......, the fast-ion measurements agree very well with the neo-classical predictions. This shows that the MHD-induced (large-scale), as well as a possible turbulence-induced (small-scale) fast-ion transport is negligible under these conditions. However, in discharges performed to study the off-axis NBI...

  18. Numerical and experimental study of the redistribution of energetic and impurity ions by sawteeth in ASDEX Upgrade

    DEFF Research Database (Denmark)

    Jaulmes, F.; Geiger, B.; Odstrčil, T.;

    2016-01-01

    In the non-linear phase of a sawtooth, the complete reconnection of field lines around the q = 1 flux surface often occurs resulting in a radial displacement of the plasma core. A complete time-dependent electromagnetic model of this type of reconnection has been developed and implemented in the ...

  19. Optics upgrade for switchyard

    Energy Technology Data Exchange (ETDEWEB)

    Kobilarcik, Thomas R.; /Fermilab

    2005-08-01

    An upgrade of the Switchyard optics is proposed. This upgrade extends the P3 (old Main Ring) lattice through enclosure C. The septa for the 3-way Meson Area split is moved from enclosure F1 to enclosure M01. The functionality of the Meson Target Train is preserved. Finally, for the purpose of demonstrating that the resulting split can be transported, a straw-man lattice is proposed for enclosure M02 and beyond.

  20. Cyclotron Institute Upgrade Project

    Energy Technology Data Exchange (ETDEWEB)

    Clark, Henry [Texas A& M University; Yennello, Sherry [Texas A& M University; Tribble, Robert [Texas A& M University

    2014-08-26

    The Cyclotron Institute at Texas A&M University has upgraded its accelerator facilities to extend research capabilities with both stable and radioactive beams. The upgrade is divided into three major tasks: (1) re-commission the K-150 (88”) cyclotron, couple it to existing beam lines to provide intense stable beams into the K-500 experimental areas and use it as a driver to produce radioactive beams; (2) develop light ion and heavy ion guides for stopping radioactive ions created with the K-150 beams; and (3) transport 1+ ions from the ion guides into a charge-breeding electron-cyclotron-resonance ion source (CB-ECR) to produce highly-charged radioactive ions for acceleration in the K-500 cyclotron. When completed, the upgraded facility will provide high-quality re-accelerated secondary beams in a unique energy range in the world.

  1. The LHCb VELO upgrade

    International Nuclear Information System (INIS)

    The LHCb experiment at the LHC plans to massively increase its data taking capabilities by running at a higher luminosity with a fully upgraded detector around 2016. This scheme is independent of (but compatible with) the plans for the SLHC upgrades. The silicon detector will be upgraded to provide a 40 MHz readout and to be able to cope with the increased radiation environment. This paper describes the options currently under consideration. A highlight of the R and D so far undertaken is a beam test during summer 2009 using the Timepix chip to track charged particles. Preliminary results are presented, including a measurement of the resolution achieved by the 55μm pitch pixel array of better than 9.5μm for perpendicular tracks and 55μm for angled tracks.

  2. The LHCb VELO upgrade

    CERN Document Server

    Collins, P; Poikela, T; Crossley, M; Kucharczyk, M; Whitehead, M; Dumps, R; Mountain, R; Artuso, M; Rodrigues, E; Tlustos, L; Papadelis, A; Buytaert, J; Blusk, S; Parkes, C; Xing, Z; Eklund, L; Coco, V; Michel, T; Campbell, M; Bowcock, T J V; Wang, J C; Akiba, K; Gligorov, V; Huse, T; Llin, L F; Gandelman, M; Plackett, R; Esperante, D; Maneuski, D; Bayer, F; Llopart, X; Alexander, M; Gallas, A; Nichols, M; van Beuzekom, M G; John, M

    2011-01-01

    The LHCb experiment at the LHC plans to massively increase its data taking capabilities by running at a higher luminosity with a fully upgraded detector around 2016. This scheme is independent of (but compatible with) the plans for the SLHC upgrades. The silicon detector will be upgraded to provide a 40 MHz readout and to be able to cope with the increased radiation environment. This paper describes the options currently under consideration. A highlight of the R\\&D so far undertaken is a beam test during summer 2009 using the Timepix chip to track charged particles. Preliminary results are presented, including a measurement of the resolution achieved by the 55 mu m pitch pixel array of better than 9.5 mu m for perpendicular tracks and 55 mu m for angled tracks. (C) 2010 Elsevier B.V. All rights reserved.

  3. ATLAS/CMS Upgrades

    CERN Document Server

    Horii, Yasuyuki; The ATLAS collaboration

    2016-01-01

    Precision studies of the Standard Model (SM) and the searches of the physics beyond the SM are ongoing at the ATLAS and CMS experiments at the Large Hadron Collider (LHC). A luminosity upgrade of LHC is planned, which provides a significant challenge for the experiments. In this report, the plans of the ATLAS and CMS upgrades are introduced. Physics prospects for selected topics, including Higgs coupling measurements, Bs,d -> mumu decays, and top quark decays through flavor changing neutral current, are also shown.

  4. The FNAL injector upgrade

    CERN Document Server

    Tan, C Y; Duel, K L; Lackey, J R; Pellico, W A

    2012-01-01

    The present FNAL H- injector has been operational since the 1970s and consists of two magnetron H- sources and two 750 keV Cockcroft-Walton Accelerators. In the upgrade, both slit-type magnetron sources will be replaced with circular aperture sources, and the Cockcroft-Waltons with a 200 MHz RFQ (radio frequency quadrupole). Operational experience at BNL (Brookhaven National Laboratory) has shown that the upgraded source and RFQ will be more reliable, improve beam quality and require less manpower than the present system.

  5. The LHCb VELO upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho Akiba, Kazuyoshi, E-mail: Kazuyoshi.Akiba@cern.ch

    2013-12-11

    The LHCb experiment plans to have a fully upgraded detector and data acquisition system in order to take data with instantaneous luminosities up to 5 times greater than currently. For this reason the first tracking and vertexing detector, the VELO, will be completely redesigned to be able to cope with the much larger occupancies and data acquisition rates. Two main design alternatives, micro-strips or pixel detectors, are under consideration to build the upgraded detector. This paper describes the options presently under consideration, as well as a few highlights of the main aspects of the current R and D. Preliminary results using a pixel telescope are also presented.

  6. Statistical analysis of the global energy confinement time in ohmic discharges in the ASDEX tokamak

    International Nuclear Information System (INIS)

    In ohmic discharges in all tokamaks at low plasma densities the global energy confinement time, τE, increases almost linearly with the density (LOC, linear ohmic confinement). In tokamaks with sufficiently large dimensions, τE saturates at a critical density (ASDEX bar ne- ≅ 3 x 1019 m-3) and is nearly constant at higher densities (SOC, saturated ohmic confinement). In the same density region some experiments report a further confinement regime for deuterium discharges in which τE exceeds the saturated value and is further increased (IOC, improved ohmic confinement). There the global energy confinement time roughly behaves as in the LOC regime. For both the LOC and the SOC regimes an isotope effect, i.e. the dependence of τ on the ion mass, is reported as an additional aspect of the ohmic energy confinement. A statistical analysis is performed to identify the parameters which are responsible for the properties of the energy confinement in these discharges in ASDEX. In contrast to earlier reports on confinement time scalings in ASDEX OH, only discharges with a full experimental description of kinetic electron and ion parameters, i.e. profiles of densities, temperatures and Zeff, are used to evaluate the energy contents of both species. By means of statistics it is shown that the characteristics of τE are mainly caused by the behaviour of the electron energy flux and the ohmic input power. The ion energy flux, does not play a significant role. Furthermore, the IOC regime is explained as a continuation of the low-density LOC regime. Both the isotope effect and the density dependence of τE are caused by features of the electron energy transport. (Author)

  7. Upgrade of the BATMAN test facility for H− source development

    International Nuclear Information System (INIS)

    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

  8. 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.

  9. Eastern Sources of Invitational Education.

    Science.gov (United States)

    Ryback, David

    1993-01-01

    Presents historical perspective suggesting that invitational theory shares many beliefs with ancient Eastern philosophies. Submits that teachers and other educators who embrace the invitational perspective may benefit from an understanding of Eastern principles. Briefly describes Buddhism, Confucianism, Taoism, Zen Buddhism, and their relevance to…

  10. Invitation to critical mathematics education

    CERN Document Server

    Skovsmose, Ole

    2012-01-01

    Invitation to Critical Mathematics Education deals with a range of crucial topics. Among these are students' foreground, landscapes of investigation, and mathematics in actions. The book is intended for a broad audience: educators, students, teachers, policy makers, anybody interested in the further development of mathematics education. The book discusses concerns and preoccupation. This way it provides an invitation into critical mathematics education.

  11. The particle fluxes in the edge plasma during discharges with improved ohmic confinement in ASDEX

    International Nuclear Information System (INIS)

    In the regime of Improved Ohmic Confinement (IOC) in ASDEX the energy confinement time τE increases linearly with increasing line-averaged density n-bare up to the density limit. The establishment of the IOC is accompanied by a substantial reduction of the external gas feed, concomitant with large decreases of all plasma edge fluxes. However, the data do not supply conclusive evidence that the IOC is primarily connected with the recycling conditions. More recent observations with very clean machine conditions seem to indicate that the impurity radiation plays a significant role. (author)

  12. Upgrade of telephone exchange

    CERN Multimedia

    2006-01-01

    As part of the upgrade of telephone services, work will be carried out on the CERN switching centre between Monday 23 October 8.00 p.m. and Tuesday 24 October 2.00 a.m. Telephone services may be disrupted and possibly even interrupted during this operation. We apologise in advance for any inconvenience this may cause. CERN TELECOM Service

  13. Upgrading Undergraduate Biology Education

    Science.gov (United States)

    Musante, Susan

    2011-01-01

    On many campuses throughout the country, undergraduate biology education is in serious need of an upgrade. During the past few decades, the body of biological knowledge has grown exponentially, and as a research endeavor, the practice of biology has evolved. Education research has also made great strides, revealing many new insights into how…

  14. OMEGA Upgrade preliminary design

    International Nuclear Information System (INIS)

    The OMEGA laser system at the Laboratory for Laser Energetics of the University of Rochester is the only major facility in the United States capable of conducting fully diagnosed, direct-drive, spherical implosion experiments. As such, it serves as the national Laser Users Facility, benefiting scientists throughout the country. The University's participation in the National Inertial Confinement Fusion (ICF) program underwent review by a group of experts under the auspices of the National Academy of Sciences (the Happer Committee) in 1985. The Happer Committee recommended that the OMEGA laser be upgraded in energy to 30 kJ. To this end, Congress appropriated $4,000,000 for the preliminary design of the OMEGA Upgrade, spread across FY88 and FY89. This document describes the preliminary design of the OMEGA Upgrade. The proposed enhancements to the existing OMEGA facility will result in a 30-kHJ, 351-nm, 60-beam direct-drive system, with a versatile pulse-shaping facility and a 1%--2% uniformity of target drive. The Upgrade will allow scientists to explore the ignition-scaling regime, and to study target behavior that is hydrodynamically equivalent to that of targets appropriate for a laboratory microfusion facility (LMF). In addition, it will be possible to perform critical interaction experiments with large-scale-length uniformly irradiated plasmas

  15. Lightweight incremental application upgrade

    NARCIS (Netherlands)

    Storm, T. van der

    2006-01-01

    I present a lightweight approach to incremental application upgrade in the context of component-based software development. The approach can be used to efficiently implement an automated update feature in a platform and programming language agnostic way. A formal release model is presented which ens

  16. SRS control system upgrade requirements

    International Nuclear Information System (INIS)

    This document defines requirements for an upgrade of the Sodium Removal System (SRS) control system. The upgrade is being performed to solve a number of maintainability and operability issues. The upgraded system will provide the same functions, controls and interlocks as the present system, and in addition provide enhanced functionality in areas discussed in this document

  17. By invitation only

    CERN Multimedia

    Antonella Del Rosso

    2011-01-01

    The Hôtel Métropole in Brussels is a legendary conference venue that will ring a bell to all physicists. 100 years after the first meeting of the Conseil de Physique Solvay, a representative group of the world’s most eminent physicists met again in October this year in the Excelsior Room to discuss “The Theory of the Quantum World”. Three members of CERN's Theory Group were invited to participate. Gian Giudice, one of them, shares with us his thoughts and impressions about this exclusive conference.   Attendees at the 25th Solvay Conference on Physics, Brussels. Photo provided by "International Solvay Institutes". “In the tradition of the Solvay Conferences, this is a discussion-oriented meeting with few talks by rapporteurs.” Thus reads the Introduction to the Scientific Programme of the Solvay Conference on Physics. In the Conference programme, the rapporteurs speak for only 30 minutes,...

  18. The ASDEX 100 keV neutral lithium beam diagnostic gun

    International Nuclear Information System (INIS)

    The neutral lithium beam gun intended for measurement of the poloidal magnetic field and of the density gradient in the scrape-off layer of ASDEX is described, and test results over a beam energy range of 27-100 keV are presented. In the gun, lithium ions are extracted from a solid emitter (#betta#-Eurcryptite) in a Pierce-type configuration, accelerated and focused in a two-tube immersion lens, and neutralized in a charge-exchange cell using sodium. The beam can be pulsed from less than one to several seconds, depending on experimental needs. At a distance of 165 cm from the gun the neutral beam equivalent current is typically greater than 1 mA (0.16 mA) for a beam energy of 100 keV (27 keV), the beam FWHM being about 8-9 mm. It is found that to produce a particular beam with a certain ratio must be maintained between the extraction and total beam voltages, this relationship depending in turn on the emitter-extractor separation. The principal features which distinguish the ASDEX gun from that employed on W7a are the greater compactness - all the active elements, i.e. emitter, extractor, lens, deflection plates and neutralizer, are contained with 57 cm - and the vacuum vessel, which simultaneously serves as the magnetic shielding. (orig.)

  19. The particle fluxes in the edge plasma during discharges with improved ohmic confinement in ASDEX

    International Nuclear Information System (INIS)

    In the recent experimental period of ASDEX a new regime of improved ohmic confinement (IOC) was discovered. So far the energy confinement time τE increased linearly with increasing line averaged density ne up to ne = 3·1013 cm-3 saturated, however, at higher densities. In the new IOC regime τE increases further with increasing ne up to ∼5·1013 cm-3. The IOC regime is achieved for D2 discharges only since the last modification of the ASDEX divertor which substantially increased the recycling from the divertor through the divertor slits. It also led to a reduction in gas consumption for a discharge by a factor of about 2. As it appears, the high fuelling rate required during a fast ramp-up of the plasma density leads to a transition into the Saturated Ohmic Confinememt (SOC) regime. Vice versa, the strong reduction in the external gas feed when the preprogrammed density plateau is reached seems to be essential for establishing the IOC. It is characterized by a pronounced peaking of the density profile. During the transition from the SOC to the IOC regime large variations in the signals of all edge and divertor related diagnostics are observed. In this paper we concentrate on the results of the Low Energy Neutral Particle Analyser (LENA), the sniffer probe, on the mass spectrometers measuring the divertor exhaust pressure. (author) 7 refs., 2 figs

  20. Edge physics and its impact on the improved ohmic confinement in ASDEX

    International Nuclear Information System (INIS)

    The edge conditions play a crucial role in achieving and maintaining the improved ohmic confinement (IOC) regime in ASDEX as has been stated by Haas et al. (1988) and Soeldner et al. (1988). This new regime is obtained after divertor reconstruction in deuterium discharges when the gas puffing is substantially reduced. IOC is then characterized by peaked density profiles and the linear scaling of the energy confinement time τE with the line-averaged density ne is recovered up to the density limit. In this paper, we discuss the evolution of the edge parameters in the transition from the linear (LOC) and then saturated (SOC) to the improved (IOC) ohmic regime. In addition, we describe the edge plasma mainly in terms of edge parameters like the separatrix density instead of bulk parameters such as the line-averaged density. This gives us the opportunity to identify and separate edge effects from the central behaviour. The data in the vicinity of the separatrix stem mainly from the single-pulse multipoint Thomson scattering system, the lithium beam spectroscopy, the Langmuir probe, and the time-of-flight spectrometer in ASDEX. For comparison, we will sometimes use measurements in the divertor chamber by electric triple probes and ionization gauges. (author) 6 refs., 3 figs

  1. Analysis of the ion energy transport in ohmic discharges in the ASDEX tokamak

    International Nuclear Information System (INIS)

    An analysis of the local ion energy transport is performed for more than one hundred well documented ohmic ASDEX discharges. These are characterized by three different confinement regimes: the linear ohmic confinement (LOC), the saturated ohmic confinement (SOC) and the improved ohmic confinement (IOC). All three are covered by this study. To identify the most important local transport mechanism of the ion heat, the ion power balance equation is analyzed. Two methods are used: straightforward calculation with experimental data only, and a comparison of measured and calculated profiles of the ion temperature and the ion heat conductivity, respectively. A discussion of the power balance shows that conductive losses dominate the ion energy transport in all ohmic discharges of ASDEX. Only inside the q=1-surface losses due to sawtooth activity play a role, while at the edge convective fluxes and CX-losses influence the ion energy transport. Both methods lead to the result that both the ion temperature and the ion heat conductivity are consistent with predictions of the neoclassical theory. Enhanced heat losses as suggested by theories eg. on the basis of ηi modes can be excluded. (orig.)

  2. Characterizing the edge plasma of different ohmic confinement regimes in ASDEX

    International Nuclear Information System (INIS)

    To compare different ohmic confinement regimes in ASDEX, the edge conditions are analyzed in detail. The results show that the improved ohmic confinement comes along with a drop of the separatrix density. This drop allows density profile to peak and seems to be the trigger of a change in the transport. Simultaneously, a universal scaling between the electron temperature and the electron density at the separatrix prevails for all ohmic scenarios. In addition, the total particle flux across the separatrix is evaluated and found to be strongly correlated to the separatrix density. Thus, the associated convective energy loss contributes less to the total energy losses when the confinement is improved. Since the correlations between edge parameters do not change in different ohmic confinement regimes of ASDEX, the edge physics remains about the same. Improved ohmic confinement is then characterized by an optimum separatrix density which provides a sufficient high edge temperature together with low particle fluxes. These optimum conditions then yield the maximum particle confinement. (orig.)

  3. Bid invitations for nuclear power stations

    International Nuclear Information System (INIS)

    Types of bid invitations, basic requirements on bid invitation documents, basic content of a turnkey bid invitation (bid invitation letter, instructions to the bidders, terms and conditions of the draft contract, technical specifications, site data and information), nuclear fuel procurement, differences turnkey - non-turnkey, legal, commerical, and technical matters concerning the contract document. (HP)

  4. The LHCb Upgrade

    CERN Document Server

    Alessio, Federico

    2013-01-01

    The LHCb experiment is designed to perform high-precision measurements of CP violation and search for New Physics using the enormous flux involving beauty and charm quarks produced at the LHC. The operation and the results obtained from the data collected in 2010 and 2011 demonstrate that the detector is robust and functioning very well. However, the limit of 1 fb^-1 of data per nominal year cannot be overcome without improving the detector. We therefore plan for an upgraded spectrometer by 2018 with a 40 MHz readout and a much more flexible software-based triggering system that will increase the data rate as well as the efficiency specially in the hadronic channels. Here we present the LHCb detector upgrade plans, based on the Letter of Intent and Framework Technical Design Report.

  5. The Pierre Auger Observatory Upgrade - Preliminary Design Report

    CERN Document Server

    Aab, A; Aglietta, M; Ahn, E J; Samarai, I Al; Albuquerque, I F M; Allekotte, I; Allison, P; Almela, A; Castillo, J Alvarez; Alvarez-Muñiz, J; Batista, R Alves; Ambrosio, M; Aminaei, A; Anchordoqui, L; Andringa, S; Aramo, C; Arqueros, F; Arsene, N; Asorey, H; Assis, P; Aublin, J; Ave, M; Avenier, M; Avila, G; Awal, N; Badescu, A M; Barber, K B; Bäuml, J; Baus, C; Beatty, J J; Becker, K H; Bellido, J A; Berat, C; Bertaina, M E; Bertou, X; Biermann, P L; Billoir, P; Blaess, S G; Blanco, A; Blanco, M; Blazek, J; Bleve, C; Blümer, H; Boháčová, M; Boncioli, D; Bonifazi, C; Borodai, N; Brack, J; Brancus, I; Bridgeman, A; Brogueira, P; Brown, W C; Buchholz, P; Bueno, A; Buitink, S; Buscemi, M; Caballero-Mora, K S; Caccianiga, B; Caccianiga, L; Candusso, M; Caramete, L; Caruso, R; Castellina, A; Cataldi, G; Cazon, L; Cester, R; Chavez, A G; Chiavassa, A; Chinellato, J A; Chudoba, J; Cilmo, M; Clay, R W; Cocciolo, G; Colalillo, R; Coleman, A; Collica, L; Coluccia, M R; Conceição, R; Contreras, F; Cooper, M J; Cordier, A; Coutu, S; Covault, C E; Cronin, J; Dallier, R; Daniel, B; Dasso, S; Daumiller, K; Dawson, B R; de Almeida, R M; de Jong, S J; De Mauro, G; Neto, J R T de Mello; De Mitri, I; de Oliveira, J; de Souza, V; del Peral, L; Deligny, O; Dembinski, H; Dhital, N; Di Giulio, C; Di Matteo, A; Diaz, J C; Castro, M L Díaz; Diogo, F; Dobrigkeit, C; Docters, W; D'Olivo, J C; Dorofeev, A; Hasankiadeh, Q Dorosti; Dova, M T; Ebr, J; Engel, R; Erdmann, M; Erfani, M; Escobar, C O; Espadanal, J; Etchegoyen, A; Falcke, H; Fang, K; Farrar, G; Fauth, A C; Fazzini, N; Ferguson, A P; Fernandes, M; Fick, B; Figueira, J M; Filevich, A; Filipčič, A; Fox, B D; Fratu, O; Freire, M M; Fuchs, B; Fujii, T; García, B; Garcia-Pinto, D; Gate, F; Gemmeke, H; Gherghel-Lascu, A; Ghia, P L; Giaccari, U; Giammarchi, M; Giller, M; Głas, D; Glaser, C; Glass, H; Golup, G; Berisso, M Gómez; Vitale, P F Gómez; González, N; Gookin, B; Gordon, J; Gorgi, A; Gorham, P; Gouffon, P; Griffith, N; Grillo, A F; Grubb, T D; Guarino, F; Guedes, G P; Hampel, M R; Hansen, P; Harari, D; Harrison, T A; Hartmann, S; Harton, J L; Haungs, A; Hebbeker, T; Heck, D; Heimann, P; Hemery, N; Herve, A E; Hill, G C; Hojvat, C; Hollon, N; Holt, E; Homola, P; Hörandel, J R; Horvath, P; Hrabovský, M; Huber, D; Huege, T; Insolia, A; Isar, P G; Jandt, I; Jansen, S; Jarne, C; Johnsen, J A; Josebachuili, M; Kääpä, A; Kambeitz, O; Kampert, K H; Kasper, P; Katkov, I; Kégl, B; Keilhauer, B; Keivani, A; Kemp, E; Kieckhafer, R M; Klages, H O; Kleifges, M; Kleinfeller, J; Krause, R; Krohm, N; Krömer, O; Kuempel, D; Mezek, G Kukec; Kunka, N; LaHurd, D; Latronico, L; Lauer, R; Lauscher, M; Lautridou, P; Coz, S Le; Lebrun, D; Lebrun, P; de Oliveira, M A Leigui; Letessier-Selvon, A; Lhenry-Yvon, I; Link, K; Lopes, L; López, R; Casado, A López; Louedec, K; Lu, L; Lucero, A; Malacari, M; Maldera, S; Mallamaci, M; Maller, J; Mandat, D; Mantsch, P; Mariazzi, A G; Marin, V; Mariş, I C; Marsella, G; Martello, D; Martin, L; Martinez, H; Bravo, O Martínez; Martraire, D; Meza, J J Masías; Mathes, H J; Mathys, S; Matthews, J; Matthews, J A J; Matthiae, G; Maurizio, D; Mayotte, E; Mazur, P O; Medina, C; Medina-Tanco, G; Meissner, R; Mello, V B B; Melo, D; Menshikov, A; Messina, S; Meyhandan, R; Micheletti, M I; Middendorf, L; Minaya, I A; Miramonti, L; Mitrica, B; Molina-Bueno, L; Mollerach, S; Montanet, F; Morello, C; Mostafá, M; Moura, C A; Muller, M A; Müller, G; Müller, S; Mussa, R; Navarra, G; Navas, S; Necesal, P; Nellen, L; Nelles, A; Neuser, J; Nguyen, P H; Niculescu-Oglinzanu, M; Niechciol, M; Niemietz, L; Niggemann, T; Nitz, D; Nosek, D; Novotny, V; Nožka, L; Ochilo, L; Oikonomou, F; Olinto, A; Pacheco, N; Selmi-Dei, D Pakk; Palatka, M; Pallotta, J; Papenbreer, P; Parente, G; Parra, A; Paul, T; Pech, M; Pȩkala, J; Pelayo, R; Pepe, I M; Perrone, L; Petermann, E; Peters, C; Petrera, S; Petrov, Y; Phuntsok, J; Piegaia, R; Pierog, T; Pieroni, P; Pimenta, M; Pirronello, V; Platino, M; Plum, M; Porcelli, A; Porowski, C; Prado, R R; Privitera, P; Prouza, M; Purrello, V; Quel, E J; Querchfeld, S; Quinn, S; Rautenberg, J; Ravel, O; Ravignani, D; Reinert, D; Revenu, B; Ridky, J; Riggi, S; Risse, M; Ristori, P; Rizi, V; de Carvalho, W Rodrigues; Fernandez, G Rodriguez; Rojo, J Rodriguez; Rodríguez-Frías, M D; Rogozin, D; Rosado, J; Roth, M; Roulet, E; Rovero, A C; Saffi, S J; Saftoiu, A; Salamida, F; Salazar, H; Saleh, A; Greus, F Salesa; Salina, G; Sánchez, F; Sanchez-Lucas, P; Santos, E; Santos, E M; Sarazin, F; Sarkar, B; Sarmento, R; Sato, R; Scarso, C; Schauer, M; Scherini, V; Schieler, H; Schmidt, D; Scholten, O; Schoorlemmer, H; Schovánek, P; Schröder, F G; Schulz, A; Schulz, J; Schumacher, J; Sciutto, S J; Segreto, A; Settimo, M; Shadkam, A; Shellard, R C; Sidelnik, I; Sigl, G; Sima, O; Śmiałkowski, A; Šmída, R; Snow, G R; Sommers, P; Sorokin, J; Squartini, R; Srivastava, Y N; Stanca, D; Stanič, S; Stapleton, J; Stasielak, J; Stephan, M; Stutz, A; Suarez, F; Suomijärvi, T; Supanitsky, A D; Sutherland, M S; Swain, J; Szadkowski, Z; Taborda, O A; Tapia, A; Tepe, A; Theodoro, V M; Timmermans, C; Peixoto, C J Todero; Toma, G; Tomankova, L; Tomé, B; Tonachini, A; Elipe, G Torralba; Machado, D Torres; Travnicek, P; Trini, M; Ulrich, R; Unger, M; Urban, M; Galicia, J F Valdés; Valiño, I; Valore, L; van Aar, G; van Bodegom, P; Berg, A M van den; van Velzen, S; van Vliet, A; Varela, E; Cárdenas, B Vargas; Varner, G; Vasquez, R; Vázquez, J R; Vázquez, R A; Veberič, D; Verzi, V; Vicha, J; Videla, M; Villaseñor, L; Vlcek, B; Vorobiov, S; Wahlberg, H; Wainberg, O; Walz, D; Watson, A A; Weber, M; Weidenhaupt, K; Weindl, A; Werner, F; Widom, A; Wiencke, L; Wilczyński, H; Winchen, T; Wittkowski, D; Wundheiler, B; Wykes, S; Yang, L; Yapici, T; Yushkov, A; Zas, E; Zavrtanik, D; Zavrtanik, M; Zepeda, A; Zhu, Y; Zimmermann, B; Ziolkowski, M; Zong, Z; Zuccarello, F

    2016-01-01

    The Pierre Auger Observatory has begun a major Upgrade of its already impressive capabilities, with an emphasis on improved mass composition determination using the surface detectors of the Observatory. Known as AugerPrime, the upgrade will include new 4 m$^2$ plastic scintillator detectors on top of all 1660 water-Cherenkov detectors, updated and more flexible surface detector electronics, a large array of buried muon detectors, and an extended duty cycle for operations of the fluorescence detectors. This Preliminary Design Report was produced by the Collaboration in April 2015 as an internal document and information for funding agencies. It outlines the scientific and technical case for AugerPrime. We now release it to the public via the arXiv server. We invite you to review the large number of fundamental results already achieved by the Observatory and our plans for the future.

  6. The Pierre Auger Observatory Upgrade - Preliminary Design Report

    Energy Technology Data Exchange (ETDEWEB)

    Aab, Alexander [Univ. Siegen (Germany); et al.

    2016-04-12

    The Pierre Auger Observatory has begun a major Upgrade of its already impressive capabilities, with an emphasis on improved mass composition determination using the surface detectors of the Observatory. Known as AugerPrime, the upgrade will include new 4 m2 plastic scintillator detectors on top of all 1660 water-Cherenkov detectors, updated and more flexible surface detector electronics, a large array of buried muon detectors, and an extended duty cycle for operations of the fluorescence detectors. This Preliminary Design Report was produced by the Collaboration in April 2015 as an internal document and information for funding agencies. It outlines the scientific and technical case for AugerPrime. We now release it to the public via the arXiv server. We invite you to review the large number of fundamental results already achieved by the Observatory and our plans for the future.

  7. ATLAS/CMS Upgrades

    CERN Document Server

    Horii, Yasuyuki; The ATLAS collaboration

    2016-01-01

    Precise Higgs measurements and new physics searches are planned at LHC (HL-LHC) with integrated luminosity of 300 fb^{-1} (3000 fb^{-1}). An increased peak luminosity provides a significant challenge for the experiments. In this presentation, the plans for the ATLAS and CMS upgrades are introduced. Physics prospects for some topics related with ‘flavour’, e.g Higgs couplings, B_{s, d}->mumu, and FCNC top decays, are also shown.

  8. Software Upgrades under Monopoly

    OpenAIRE

    Jiri Strelicky; Kresimir Zigic

    2013-01-01

    We study price discrimination in a monopolistic software market. The monopolist charges different prices for the upgrade version and for the full version. Consumers are heterogeneous in taste for infinitely durable software and there is no resale. We show that price discrimination leads to a higher software quality but raises both absolute price and price per quality. This price discrimination does not increase sales and it decreases the total number of consumers compared to no discrimination...

  9. Optimizing pyrolysis gasoline upgrading

    Energy Technology Data Exchange (ETDEWEB)

    Coupard, V.; Cosyns, J.; Debuisschert, Q.; Travers, Ph. [Axens (France). Kinetics and Catalysis Div.

    2002-06-01

    Stringent environmental regulations for European Gasoline will mean decrease in Pygas in Gasoline pool. Pygas upgrading routes have been developed to produce added value products such as dicyclopentadiene, cyclopentane, improved olefin cracking stocks and desulfurized aromatic streams. Examples will be presented with Economics. New generation Nickel/Palladium catalysts in the 1{sup st} stage Pygas hydrogenation units will be discussed related to increasing capacity and service life. (orig.)

  10. LHCb VELO Upgrade

    CERN Document Server

    Hennessy, Karol

    2016-01-01

    The upgrade of the LHCb experiment, scheduled for LHC Run-III, scheduled to start in 2021, will transform the experiment to a trigger-less system reading out the full detector at 40 MHz event rate. All data reduction algorithms will be executed in a high-level software farm enabling the detector to run at luminosities of $2\\times10^{33} \\mathrm{cm}^{-2}\\mathrm{s}^{-1}$. The Vertex Locator (VELO) is the silicon vertex detector surrounding the interaction region. The current detector will be replaced with a hybrid pixel system equipped with electronics capable of reading out at 40 MHz. The upgraded VELO will provide fast pattern recognition and track reconstruction to the software trigger. The silicon pixel sensors have $55\\times55 \\mu m^{2}$ pitch, and are read out by the VeloPix ASIC, from the Timepix/Medipix family. The hottest region will have pixel hit rates of 900 Mhits/s yielding a total data rate of more than 3 Tbit/s for the upgraded VELO. The detector modules are located in a separate vacuum, separate...

  11. The LHCb VELO upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Rodríguez Pérez, Pablo, E-mail: pablo.rodriguez@usc.es

    2013-12-01

    LHCb is a forward spectrometer experiment dedicated to the study of new physics in the decays of beauty and charm hadrons produced in proton collisions at the Large Hadron Collider (LHC) at CERN. The VErtex LOcator (VELO) is the microstrip silicon detector surrounding the interaction point, providing tracking and vertexing measurements. The upgrade of the LHCb experiment, planned for 2018, will increase the luminosity up to 2×10{sup 33} cm{sup −2} s{sup −1} and will perform the readout as a trigger-less system with an event rate of 40 MHz. Extremely non-uniform radiation doses will reach up to 5×10{sup 15} 1 MeV n{sub eq}/cm{sup 2} in the innermost regions of the VELO sensors, and the output data bandwidth will be increased by a factor of 40. An upgraded detector is under development based in a pixel sensor of the Timepix/Medipix family, with 55×55μm{sup 2} pixels. In addition a microstrip solution with finer pitch, higher granularity and thinner than the current detector is being developed in parallel. The current status of the VELO upgrade program will be described together with recent testbeam results.

  12. The LHCb VELO upgrade

    Science.gov (United States)

    Dosil Suárez, Álvaro

    2016-07-01

    The upgrade of the LHCb experiment, planned for 2019, will transform the experiment to a trigger-less system reading out the full detector at 40 MHz event rate. All data reduction algorithms will be executed in a high-level software farm. The upgraded detector will run at luminosities of 2×1033 cm-2 s-1 and probe physics beyond the Standard Model in the heavy flavour sector with unprecedented precision. The Vertex Locator (VELO) is the silicon vertex detector surrounding the interaction region. The current detector will be replaced with a hybrid pixel system equipped with electronics capable of reading out at 40 MHz. The detector comprises silicon pixel sensors with 55×55 μm2 pitch, read out by the VeloPix ASIC, based on the TimePix/MediPix family. The hottest region will have pixel hit rates of 900 Mhits/s yielding a total data rate more than 3 Tbit/s for the upgraded VELO. The detector modules are located in a separate vacuum, separated from the beam vacuum by a thin custom made foil. The detector halves are retracted when the beams are injected and closed at stable beams, positioning the first sensitive pixel at 5.1 mm from the beams. The material budget will be minimised by the use of evaporative CO2 coolant circulating in microchannels within 400 μm thick silicon substrates.

  13. An Invitation to Wander

    Directory of Open Access Journals (Sweden)

    Lavrova L.

    2011-03-01

    Full Text Available "An invitation to wander" is Lyudmila Lavrova’s introduction to the book Contrasts, collection of poems by Hamlet Isaxanli which were translated from Azerbaijani into Russian by Alla Akhundova (Izograf, Moscow, 2006. Lavrova describes Isaxanli’s poetry as "transparent and simple", comparing him to a medieval Arab-Islamic philosopher because of the themes throughout his works of "Many and One". Even in small details of life and nature, he finds cause to revere the Divine. His poetry is also notable for its connection to mathematics and its foundation of reason. This is logical given Isakhanli’s background as a mathematician; Lavrova offers an extensive biography of the poet and a list of awards he has won. Despite the mathematic and rational foundations of his work, his poetry is not limited to being appreciated by a Western audience; Lavrova points out that Isakhanli’s poetry is also considered beautiful by Eastern standards of aesthetics. In fact, from an Eastern perspective, even more important than his "success" is his personal character, which is also worthy of esteem. Lavrova also discusses the origins of his inspiration for his works, concluding that the goal of Isakhanli’s poetry is to "nurture morality".‖

  14. INVITATION FROM THE UBS

    CERN Multimedia

    UBS SA

    2000-01-01

    Via its Web pages (http://www.ubs.com), the UBS offers you direct access to all its telebanking services, namely:information relating to accounts and custody accounts (balances, debits and credits);stock market information and placing of orders;domestic and foreign payment transactions.These supplementary and inexpensive banking services mean that you no longer have to go to the bank to obtain the information you require and are not therefore limited by bank opening times.The UBS will be holding two sessions on the CERN site to present this modern product on:25.4.2000 (in French),26.4.2000 (in English).The agenda will be as follows:12.00 to 12.40 p.m.Presentation of the product;12.40 to 13.10 p.m.Question-and-answer session;13.10 to 14.00 p.m.Buffet and discussions.To enable us to meet your requirements and to expedite matters, we invite you to register for one of these sessions by sending an e-mail or letter to:pierre.guyenon@ubs.com before 7.4.2000 indicating:your surname and first name, the account number(...

  15. LHCb Upgrade: Upstream Tracker

    CERN Document Server

    AUTHOR|(CDS)2082337

    2015-01-01

    The upgraded LHCb detector will run at an instantaneous luminosity of 2 X 10$^{33}$ cm$^{-2}$ s$^{-1}$, five times higher than in the current configuration, and will have a full 40 MHz readout. In order to cope with these higher instantaneous rates, the tracking detector upstream of the LHCb dipole magnet, called Tracker Turicensis (TT) [1], will be replaced by the Upstream Tracker (UT) [2]. The conceptual design of the UT and the current status of the R&D are presented here.

  16. Upgrading of the tandem

    International Nuclear Information System (INIS)

    The program of the tandem-linac accelerator system is summarized under the following headings: operating experience for the tandem, operation of the superconducting linac, upgrading of the tandem (ion sources, vacuum systems, terminal box, stripping foils, beam bunching), installation of the booster, planned accelerator system improvements, experimental facilities development at the super conducting-linac booster (new beam line, layout and installation of the 00 beam line in the new experiment area, beam optics calculations, 65-in. scattering chamber, split-pole spectrograph, sum/multiplicity detector, nuclear target making and development), and university use of the tandem accelerator

  17. Determination of impurity concentrations and Zeff by VUV spectroscopy on ASDEX

    International Nuclear Information System (INIS)

    The impurity concentrations and corresponding Zeff contributions as well as the dilution of the deuterium background plasma in ASDEX are determined by VUV spectroscopy. The methods used are described in detail. We describe the absolute calibration of our VUV survey spectrometer with two different calibration sources, as well as our ZEDIFF time-dependent transport code, used for interpreting the spectroscopic measurements. The assessed spectroscopic Zeff compares quite well with the bremsstrahlung Zeff as demonstrated for a number of representative ohmically and additionally heated discharges. In order to obtain these results readily on a shot-to-shot basis at the end of each discharge, a simplified fast evaluation method is introduced. This fast analysis method yields the central impurity concentrations, the central Zeff contributions, and the dilution of the deuterons. Again, the results from the fast analysis method agree well with those from our extended transport code treatment and with the bremsstrahlung Zeff. (orig.)

  18. Parametric investigation of the density profile in the scrape-off layer of ASDEX

    Science.gov (United States)

    McCormick, K.; Pietrzyk, Z. A.; Murmann, H.; Lenoci, M.; ASDEX Team; Becker, G.; Bosch, H. S.; Brocken, H.; Bühl, K.; Eberhagen, A.; Eckhartt, D.; Fussmann, G.; Gehre, O.; Gernhardt, J.; Gierke, G. V.; Glock, E.; Gruber, O.; Haas, G.; Hofmann, J.; Izvozchikov, A.; Janeschitz, G.; Karger, F.; Kaufmann, M.; Keilhacker, M.; Klüber, O.; Kornherr, M.; Lackner, K.; Lang, R. S.; Leuterer, F.; Lisitano, G.; Mast, F.; Mayer, H. M.; Meisel, D.; Mertens, V.; Müller, E. R.; Neuhauser, J.; Noterdaeme, J.-M.; Niedermeyer, H.; Poschenrieder, W.; Rapp, H.; Riedler, H.; Röhr, H.; Roth, J.; Ryter, F.; Sandmann, W.; Schneider, F.; Setzensack, C.; Siller, G.; Smeulders, P.; Söldner, F. X.; Speth, E.; Steinmetz, K.; Steuer, K.-H.; Tsois, N.; Ugniewski, S.; Vlases, G.; Vollmer, O.; Wagner, F.; Wesner, F.; Zasche, D.

    1987-02-01

    Systematic investigations of the scrape-off layer (SOL) in the midplane of ASDEX have been carried out in He, D 2 and H 2 for diverted ohmic discharges over a wide range of plasma conditions: overlinene ˜ 0.5-4.7 × 10 13 cm -3, Ip = 200-450 kA, BT = 16-23 kG, qa˜ 2.4-4.4 and POH = 200-480 kW. For the first two cm outside the separatix, ne is found to decay exponentially with an e-folding length λn given by λn = kqα (He, k = 1.32 cm, α = 0.52; D 2, k =1.29 cm, α = 0.35; H 2, k = 1.18 cm, α = 0.4) when from which follows for qa = 3: λn( D2) ˜ λn( H2) ˜ 0.8 λn( He). The qα scaling is roughly predicted by the simple formula λ n = {D ⊥ L }/{υ ∥} under the assumption D⊥ ∝ mi-0.5 (as has been observed on ASDEX for H 2 and D 2). There appears to be no explicit λn dependence on heating power. λn varies strongly with overlinene in the range overlinene ≤ 1 × 10 13 cm -3, decreasing for example (D 2,H 2; qa = 3.0), from λn ≥ 3 cm at overlinene ˜ 0.5 × 10 13 cm -3 to λn ˜ 1.9 cm for overlinene ≥ 1.5 × 10 13 cm -3, ne at the separatrix is primarily a function of overlinene.

  19. LHC Detector Upgrades

    CERN Document Server

    Gregor, I M; The ATLAS collaboration

    2014-01-01

    Since the discovery of the Higgs boson in 2012, the LHC collaborations have been preparing to expand the exciting LHC physics program to include precise measurements of the properties of the Higgs and to search increasingly remote regions of phase space for signs of physics beyond the Standard Model. This very ambitious physics program will require a series of accelerator upgrades which will steadily increase the beam luminosity over the next decade to reach a total integrated luminosity of 350 fb−1 by 2022. At that time, the LHC will undergo a major upgrade to merit a new name: the High Luminosity LHC (HL-LHC), which is being designed to deliver five times the nominal LHC instantaneous luminosity and to provide for luminosity leveling. The final goal is to extend the data set to 3000 fb−1 by the 2030ties. Operation of the experiments with increasing rates and pile-up will become more challenging and performance degradations due to the high radiation dose will need to be addressed. ATLAS and CMS will ther...

  20. The FNAL injector upgrade

    International Nuclear Information System (INIS)

    The present FNAL H- injector has been operational since the 1970s and consists of two magnetron H- sources and two 750 keV Cockcroft-Walton Accelerators. In the upgrade, both slit-type magnetron sources will be replaced with circular aperture sources, and the Cockcroft-Waltons with a 200 MHz RFQ (radio frequency quadrupole). Operational experience at BNL (Brookhaven National Laboratory) has shown that the upgraded source and RFQ will be more reliable, improve beam quality and require less manpower than the present system. The present FNAL (Fermi National Accelerator Laboratory) injector has been operational since 1978 and has been a reliable source of H- beams for the Fermilab program. At present there are two Cockcroft-Walton injectors, each with a magnetron H- source with a slit aperture. With these two sources in operation, the injector has a reliability of better than 97%. However, issues with maintenance, equipment obsolescence, increased beam quality demands and retirement of critical personnel, have made it more difficult for the continued reliable running of the H- injector. The recent past has also seen an increase in both downtime and source output issues. With these problems coming to the forefront, a new 750 keV injector is being built to replace the present system. The new system will be similar to the one at BNL (Brookhaven National Laboratory) that has a similar magnetron source with a round aperture and a 200MHz RFQ. This combination has been shown to operate extremely reliably.

  1. The STAR Tracking Upgrade

    International Nuclear Information System (INIS)

    The STAR collaboration is preparing a tracking detector upgrade, the Heavy Flavor Tracker (HFT) and the Forward GEM Tracker (FGT) to further investigate fundamental properties of the new state of strongly interacting matter produced in relativistic-heavy ion collisions at RHIC and to provide fundamental studies of the proton spin structure and dynamics in high-energy polarized proton-proton collisions at RHIC. The HFT is based on a novel two-layer CMOS active-pixel sensor detector together with a conventional two-layer silicon-strip/silicon-pad detector. The FGT upgrade will consist of six triple-GEM detectors with two dimensional readout arranged in disks along the beam axis. The FGT project has completed an extensive R and D program of industrially produced GEM foils at Tech-Etch Inc. in comparison to GEM foils produced at CERN based on optical measurements, test beam and 55Fe source measurements of a triple-GEM prototype detector using 10 x 10 cm2 GEM foils. The FGT project requires large GEM foils which are currently being tested. The HFT and FGT design, the status of full prototype tests along with the HFT and FGT construction and the installation schedule will be presented. (author)

  2. The Fermilab Linac Upgrade

    International Nuclear Information System (INIS)

    The Fermilab Linac Upgrade is planned to increase the energy of the H- linac from 200 to 400 MeV. This is intended to reduce the incoherent space-charge tuneshift at injection into the 8 GeV Booster which can limit either the brightness or the total intensity of the beam. The Linac Upgrade will be achieved by replacing the last four 201.25 MHz drift-tube tanks which accelerate the beam from 116 to 200 MeV, with seven 805 MHz side-coupled cavity modules operating at an average axial field of abut 7.5 MV/m. This will allow acceleration to 400 MeV in the existing Linac enclosure. Each accelerator module will be driven with a klystron-based rf power supply. A prototype rf modulator has been built and tested at Fermilab, and a prototype 12 MW klystron is being fabricated by Litton Electron Devices. Fabrication of production accelerator modules is in progress. 8 figs., 4 tabs

  3. The Fermilab Linac Upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Noble, R.J.

    1991-02-01

    The Fermilab Linac Upgrade is planned to increase the energy of the H- linac from 200 to 400 MeV. This is intended to reduce the incoherent space-charge tuneshift at injection into the 8 GeV Booster which can limit either the brightness or the total intensity of the beam. The Linac Upgrade will be achieved by replacing the last four 201.25 MHz drift-tube tanks which accelerate the beam from 116 to 200 MeV, with seven 805 MHz side-coupled cavity modules operating at an average axial field of abut 7.5 MV/m. This will allow acceleration to 400 MeV in the existing Linac enclosure. Each accelerator module will be driven with a klystron-based rf power supply. A prototype rf modulator has been built and tested at Fermilab, and a prototype 12 MW klystron is being fabricated by Litton Electron Devices. Fabrication of production accelerator modules is in progress. 8 figs., 4 tabs.

  4. LHCb VELO Upgrade

    CERN Multimedia

    van Beuzekom, Martin; Ketel, Tjeerd; Gershon, Timothy; Parkes, Christopher; Reid, Matthew

    2011-01-01

    The VErtex LOcator (VELO) is a vital piece of apparatus for allowing precision measurements in hadronic physics. It provides not only superb impact parameter resolutions but also excellent momentum resolution, both important discriminating tools for precision high energy physics. This poster focuses on the R&D going into the future LHCb VELO detector. At present there are two proposed options for the upgrade; pixel chips or strip detectors. The LHCb upgrade is designed with higher luminosities and increased yields in mind. In order to get more out of the LHCb detector changes to the front end electronics will have to be made. At present, the first level hardware trigger is sets a limiting factor on the maximum efficiency for hadronic channels. As the VELO is positioned so close the proton-proton interaction region, whatever the choice of sensor, we will require efficient cooling and some proposed solutions are outlined. The LHCb TimePix telescope has had a very successful years running, with various devic...

  5. ATLAS Strip Upgrade

    CERN Document Server

    Bernabeu, J; The ATLAS collaboration

    2012-01-01

    A phased upgrade of the Large Hadron Collider (LHC) at CERN is planned. The last upgrade phase (HL-LHC) is currently foreseen in 2022-2023. It aims to increase the integrated luminosity to about ten times the original LHC design luminosity. To cope with the harsh conditions in terms of particle rates and radiation dose expected during HL-LHC operation, the ATLAS collaboration is developing technologies for a complete tracker replacement. This new detector will need to provide extreme radiation hardness and a high granularity, within the tight constraints imposed by the existing detectors and their services. An all-silicon high granularity tracking detector is proposed. An international R&D collaboration is working on the strip layers for this new tracker. A number of large area prototype planar detectors produced on p-type wafers have been designed and fabricated for use at HL-LHC. These prototype detectors and miniature test detectors have been irradiated to a set of fluences matched to HL-LHC expectatio...

  6. ATLAS Strip Upgrade

    CERN Document Server

    Bernabeu, J; The ATLAS collaboration

    2012-01-01

    A phased upgrade of the Large Hadron Collider (LHC) at CERN is planned. The last upgrade phase (HL-LHC) is currently foreseen in 2022-2023. It aims to increase the integrated luminosity to about ten times the original LHC design luminosity. To cope with the harsh conditions in terms of particle rates and radiation dose expected during HL-LHC operation, the ATLAS collaboration is developing technologies for a complete tracker replacement. This new detector will need to provide extreme radiation hardness and a high granularity, within the tight constraints imposed by the existing detectors and their services. An all-silicon high-granularity tracking detector is proposed. An international R&D collaboration is working on the strip layers for this new tracker. A number of large area prototype planar detectors produced on p-type wafers have been designed and fabricated for use at HL-LHC. These prototype detectors and miniature test detectors have been irradiated to a set of fluences matched to HL-LHC expectatio...

  7. Recharging of the ohmic-heating transformer by means of lower-hybrid current drive in the ASDEX tokamak

    Science.gov (United States)

    Leuterer, F.; Eckhartt, D.; Söldner, F.; Becker, G.; Bernhardi, K.; Brambilla, M.; Brinkschulte, H.; Derfler, H.; Ditte, U.; Eberhagen, A.; Fussman, G.; Gehre, O.; Gernhardt, J.; Gierke, G. V.; Glock, E.; Gruber, O.; Haas, G.; Hesse, M.; Janeschitz, G.; Karger, F.; Keilhacker, M.; Kissel, S.; Klüber, O.; Kornherr, M.; Lisitano, G.; Magne, R.; Mayer, H. M.; McCormick, K.; Meisel, D.; Mertens, V.; Müller, E. R.; Münich, M.; Murmann, H.; Poschenrieder, W.; Rapp, H.; Ryter, F.; Schmitter, K. H.; Schneider, F.; Siller, G.; Smeulders, P.; Steuer, K. H.; Vien, T.; Wagner, F.; Woyna, F. V.; Zouhar, M.

    1985-07-01

    Recharging of the Ohmic-heating transformer of a tokamak by means of lower-hybrid waves is demonstrated experimentally in ASDEX. The results are analyzed on the basis of a simple transformer circuit. A recharging efficiency is defined and found to depend on rf power, plasma density, and plasma resistivity modified by the applied rf power. Up to now, we achieved in our recharging experiments in ASDEX a flux swing of FİOHMdt=0.24 V sec, at an rf power of PRF=690 kW, with a pulse duration of 1 sec, while maintaining a plasma with n¯e=4×1012 cm-3 and Ip=290 kA.

  8. The D0 upgrade trigger

    International Nuclear Information System (INIS)

    The current trigger system for the D0 detector at Fermilab's Tevatron will need to be upgraded when the Min Injector is installed and the Tevatron can operate at luminosities exceeding 1032 cm-2s-1 and with a crossing time of 132 ns. We report on preliminary designs for upgrades to the trigger system for the Main Injector era

  9. Prospects for the upgraded Tevatron

    International Nuclear Information System (INIS)

    Plans and prospects for the next Fermilab collider running period, Run II (beginning in 1999), are described. The upgrades to the accelerator are discussed in the context of expected achievable instantaneous and integrated luminosity. Upgrades to the two collider detectors, CDF and D0, along with physics potential for Run II are also described. Options for Fermilab beyond Run II are mentioned

  10. Upgrading the ATLAS control system

    International Nuclear Information System (INIS)

    Heavy-ion accelerators are tools used in the research of nuclear and atomic physics. The ATLAS facility at the Argonne National Laboratory is one such tool. The ATLAS control system serves as the primary operator interface to the accelerator. A project to upgrade the control system is presently in progress. Since this is an upgrade project and not a new installation, it was imperative that the development work proceed without interference to normal operations. An additional criteria for the development work was that the writing of additional ''in-house'' software should be kept to a minimum. This paper briefly describes the control system being upgraded, and explains some of the reasons for the decision to upgrade the control system. Design considerations and goals for the new system are described, and the present status of the upgrade is discussed

  11. The STAR Tracking Upgrade

    CERN Document Server

    Simon, Frank

    2007-01-01

    The STAR experiment at the Relativistic Heavy Ion Collider RHIC studies the new state of matter produced in relativistic heavy ion collisions and the spin structure of the nucleon in collisions of polarized protons. In order to improve the capabilities for heavy flavor measurements and the reconstruction of charged vector bosons an upgrade of the tracking system both in the central and the forward region is pursued. The challenging environments of high track multiplicity in heavy ion collisions and of high luminosity in polarized proton collisions require the use of new technologies. The proposed inner tracking system, optimized for heavy flavor identification, is using active pixel sensors close to the collision point and silicon strip technology further outward. Charge sign determination for electrons and positrons from the decay of W bosons will be provide by 6 large-area triple GEM disks currently under development. A prototype of the active pixel detectors has been tested in the STAR experiment, and an e...

  12. ISTTOK control system upgrade

    International Nuclear Information System (INIS)

    Highlights: •ISTTOK fast controller. •All real-time diagnostic and actuators were integrated in the control platform. •100 μs control cycle under the MARTe framework. •The ISTTOK control system upgrade provides reliable operation with an improved operational space. -- Abstract: The ISTTOK tokamak (Ip = 4 kA, BT = 0.5 T, R = 0.46 m, a = 0.085 m) is one of the few tokamaks with regular alternate plasma current (AC) discharges scientific programme. In order to improve the discharge stability and to increase the number of AC discharge cycles a novel control system was developed. The controller acquires data from 50 analog-to-digital converter (ADC) channels of real-time diagnostics and measurements: tomography, Mirnov coils, interferometer, electric probes, sine and cosine probes, bolometer, current delivered by the power supplies, loop voltage and plasma current. The system has a control cycle of 100 μs during which it reads all the diagnostics connected to the advanced telecommunications computing architecture (ATCA) digitizers and sends the control reference to ISTTOK actuators. The controller algorithms are executed on an Intel® Q8200 chip with 4 cores running at 2.33 GHz and connected to the I/O interfaces through an ATCA based environment. The real-time control system was programmed in C++ on top of the Multi-threaded Application Real-Time executor (MARTe). To extend the duration of the AC discharges and the plasma stability a new magnetising field power supply was commissioned and the horizontal and vertical field power supplies were also upgraded. The new system also features a user-friendly interface based on HyperText Markup Language (HTML) and Javascript to configure the controller parameters. This paper presents the ISTTOK control system and the consequent update of real-time diagnostics and actuators

  13. ISTTOK control system upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, Ivo S., E-mail: ivoc@ipfn.ist.utl.pt; Duarte, Paulo; Fernandes, Horácio; Valcárcel, Daniel F.; Carvalho, Pedro J.; Silva, Carlos; Duarte, André S.; Neto, André; Sousa, Jorge; Batista, António J.N.; Carvalho, Bernardo B.

    2013-10-15

    Highlights: •ISTTOK fast controller. •All real-time diagnostic and actuators were integrated in the control platform. •100 μs control cycle under the MARTe framework. •The ISTTOK control system upgrade provides reliable operation with an improved operational space. -- Abstract: The ISTTOK tokamak (Ip = 4 kA, BT = 0.5 T, R = 0.46 m, a = 0.085 m) is one of the few tokamaks with regular alternate plasma current (AC) discharges scientific programme. In order to improve the discharge stability and to increase the number of AC discharge cycles a novel control system was developed. The controller acquires data from 50 analog-to-digital converter (ADC) channels of real-time diagnostics and measurements: tomography, Mirnov coils, interferometer, electric probes, sine and cosine probes, bolometer, current delivered by the power supplies, loop voltage and plasma current. The system has a control cycle of 100 μs during which it reads all the diagnostics connected to the advanced telecommunications computing architecture (ATCA) digitizers and sends the control reference to ISTTOK actuators. The controller algorithms are executed on an Intel{sup ®} Q8200 chip with 4 cores running at 2.33 GHz and connected to the I/O interfaces through an ATCA based environment. The real-time control system was programmed in C++ on top of the Multi-threaded Application Real-Time executor (MARTe). To extend the duration of the AC discharges and the plasma stability a new magnetising field power supply was commissioned and the horizontal and vertical field power supplies were also upgraded. The new system also features a user-friendly interface based on HyperText Markup Language (HTML) and Javascript to configure the controller parameters. This paper presents the ISTTOK control system and the consequent update of real-time diagnostics and actuators.

  14. Abstract Invited Braumann IMM 2008

    OpenAIRE

    Braumann, Carlos A.

    2009-01-01

    Invited conference of the scientific meeting II Iberian Nathematic Meeting (Badajoz, Spain, October 2008). The conference involved several applications of stochastic differential equations in population growth and animal individual growth, including the issues of extinction, existence of stationary densities and the use of Itô or Stratonovich calculus.

  15. Alberta propylene upgrading prospects

    International Nuclear Information System (INIS)

    A very significant byproduct recovery and purification scheme is at present being prepared by TransCanada Midstream (TCMS). Alberta Economic Development commissioned an independent study to identify propylene supply options while proceeding with the evaluation of various propylene derivatives with regard to their fit with the Alberta context. Identification of chemical companies with derivative interests was also accomplished. By 2005, it is estimated that 280 kilo-tonnes of propylene will be available on an annual basis from byproduct sources. Those sources are oil sands upgraders, ethylene plants and refineries. The ranges of impurities and supply costs vary between the different sources. An option being considered involves pipeline and rail receipt with a major central treating and distillation facility for the production of polymer grade (PG) propylene with propane and other smaller byproducts. Special consideration was given to three chemicals in this study, namely: polypropylene (PP), acrylonitrile (ACN), and acrylic acid (AA). Above average growth rates were identified for these chemicals: demand is growing at 6 to 7 per cent a year for both PP and ACN, while demand for AA grows at 8 per cent annually. Two other possibilities were identified, propylene oxide (PO) and phenol. The study led to the conclusion that low capital and operating costs and shipping costs to the Pacific Rim represent advantages to the development of propylene derivatives in the future in Alberta. 4 refs., 87 tabs., 7 figs

  16. MAST Upgrade - Construction Status

    CERN Document Server

    Milnes, Joe; Dhalla, Fahim; Fishpool, Geoff; Hill, John; Katramados, Ioannis; Martin, Richard; Naylor, Graham; O'Gorman, Tom; Scannell, Rory

    2015-01-01

    The Mega Amp Spherical Tokamak (MAST) is the centre piece of the UK fusion research programme. In 2010, a MAST Upgrade programme was initiated with three primary objectives, to contribute to: 1) Testing reactor concepts (in particular exhaust solutions via a flexible divertor allowing Super-X and other extended leg configurations); 2) Adding to the knowledge base for ITER (by addressing important plasma physics questions and developing predictive models to help optimise ITER performance of ITER) and 3) Exploring the feasibility of using a spherical tokamak as the basis for a fusion Component Test Facility. With the project mid-way through its construction phase, progress will be reported on a number of the critical subsystems. This will include manufacture and assembly of the coils, armour and support structures that make up the new divertors, construction of the new set coils that make up the centre column, installation of the new power supplies for powering the divertor coils and enhanced TF coil set, progr...

  17. ATLAS Future Upgrade

    CERN Document Server

    Vankov, Peter; The ATLAS collaboration

    2016-01-01

    After the successful operation at the center-of-mass energies of 7 and 8 TeV in 2010 - 2012, the LHC is ramped up and successfully took data at the center-of-mass energies of 13 TeV in 2015. Meanwhile, plans are actively advancing for a series of upgrades of the accelerator, culminating roughly ten years from now in the high-luminosity LHC (HL-LHC) project, delivering of the order of five times the LHC nominal instantaneous luminosity along with luminosity leveling. The ultimate goal is to extend the dataset from about few hundred fb−1 expected for LHC running to 3000 fb−1 by around 2035 for ATLAS and CMS. In parallel, the experiments need to be keep lockstep with the accelerator to accommodate running beyond the nominal luminosity this decade. Along with maintenance and consolidation of the detector in the past few years, ATLAS has added inner b-layer to its tracking system. The challenge of coping with the HL-LHC instantaneous and integrated luminosity, along with the associated radiation levels, requir...

  18. Luminosity upgrades on PEP

    International Nuclear Information System (INIS)

    Over the past two years the authors have explored several ideas for Luminosity Upgrades on PEP. This followed the recommendation of the Goldhaber Committee which concluded that unless PETRA uncovered new physics at higher energies then PEP should concentrate on higher luminosity at its present energy. These studies explored many schemes which involved lowering the β functions (stronger focussing) at the interaction points, as it has been employed at CESR, PETRA, DORIS II and in PEP. The first round of studies assumed that all six interaction regions would be required and that the overall chromatic aberrations which could be tolerated and corrected should not exceed their present value. This led to designs which incorporated quadrupoles for the low-β insertions which were placed inside the magnetic field region of the detectors. Because of the high fields in some of the detectors, these quadrupoles would have to be either superconducting iron-free, or permanent magnet (samarium-cobalt) designs. Although machine lattice designs were readily achievable using these techniques, the engineering complexity and the impact on detectors made these schemes rather unattractive. This forced a review of the above assumptions and led to the studies of the Mini-Maxi Beta and the Six-Fold Mini Beta schemes described in this paper. 2 figures, 1 table

  19. The STAR tracking upgrade

    International Nuclear Information System (INIS)

    The STAR experiment at the Relativistic Heavy Ion Collider RHIC studies the new state of matter produced in relativistic heavy ion collisions and the spin structure of the nucleon in collisions of polarized protons. In order to improve the capabilities for heavy flavor measurements and the reconstruction of charged vector bosons an upgrade of the tracking system both in the central and the forward region is pursued. The challenging environments of high track multiplicity in heavy ion collisions and of high luminosity in polarized proton collisions require the use of new technologies. The proposed inner tracking system, optimized for heavy flavor identification, is using active pixel sensors close to the collision point and silicon strip technology further outward. Charge sign determination for electrons and positrons from the decay of W bosons will be provide by 6 large-area triple GEM disks currently under development. A prototype of the active pixel detectors has been tested in the STAR experiment, and an extensive beam test of triple GEM detectors using GEM foils produced by Tech-Etch of Plymouth, MA has been done at Fermilab

  20. Upgrade of the MAGIC telescopes

    CERN Document Server

    Mazin, Daniel; Garczarczyk, Markus; Giavitto, Gianluca; Sitarek, Julian

    2014-01-01

    The MAGIC telescopes are two Imaging Atmospheric Cherenkov Telescopes (IACTs) located on the Canary island of La Palma. With 17m diameter mirror dishes and ultra-fast electronics, they provide an energy threshold as low as 50 GeV for observations at low zenith angles. The first MAGIC telescope was taken in operation in 2004 whereas the second one joined in 2009. In 2011 we started a major upgrade program to improve and to unify the stereoscopic system of the two similar but at that time different telescopes. Here we report on the upgrade of the readout electronics and digital trigger of the two telescopes, the upgrade of the camera of the MAGIC I telescope as well as the commissioning of the system after this major upgrade.

  1. Upgrade of manufacturing information system

    OpenAIRE

    Meglen, Štefan

    2009-01-01

    The dissertation deals with the upgrade of insufficiently developed manufacturing information system. Prior to starting the development, the possibilities and potential difficulties of development environment upgrade have been studied. Applied methodology, as well as development environment with its tools and database are discussed in the first part of the dissertation. The second part includes an overview of the manufacturing information system, focused on work order. A work order placem...

  2. WNP-2 core model upgrade

    International Nuclear Information System (INIS)

    The paper describes the core model upgrade of the WNP-2 training simulator and the reasons for the upgrade. The core model as well as the interface with the rest of the simulator are briefly described . The paper also describes the procedure that will be used by WNP-2 to update the simulator core data after future core reloads. Results from the fully integrated simulator are presented. (author)

  3. D0 Upgrade for RUN II

    CERN Document Server

    Petroff, P

    1999-01-01

    The D0 detector at The Fermilab Tevatron is undergoing a major upgrade to prepare for data taking with luminosities reaching 2 x 10^{32} cm^{-2} s^{-1}. The upgrade includes a new central tracking array, new muon detector components and electronic upgrades to many subsystems. The D0 upgraded detector will be operational for RUN II in spring 2000.

  4. Report on the low-RF-power and data-acquisition-systems of the 2.45 GHz Lower-Hybrid Transmitter at the ASDEX tokamak

    International Nuclear Information System (INIS)

    This report relates to the low-power section of the 2.45 GHz transmitter used for current drive experiments at the ASDEX tokamak. The high-RF-power section is dealt with elsewhere. Data acquisition and evaluation of quantities pertaining to the Lower Hybrid experiment are also treated here. As in the previous report on the 1.3 GHz system (M. Zouhar: 'Beschreibung des Niederleistungsteils des HF-Systems fuer die LH-Experimente in ASDEX.', IPP-report 4/218, February 1984), most space is spent in commenting upon the amplitude (power)- and phase-feedback control loops. (orig.)

  5. Upgrading inflatable door seals

    International Nuclear Information System (INIS)

    Inflatable door seals are used for airlocks in CANDU stations. They have been a significant source of unreliability and maintenance cost. A program is underway to improve their performance and reliability, backed by environmental qualification testing. Only commercial products and suppliers existed in 1993. For historical reasons, these 'existing products' did not use the most durable material then available. In hindsight, neither had they been adapted nor optimized to combat conditions often experienced in the plants-sagging doors, damaged sealing surfaces, and many thousands of openings and closings per year. Initial attempts to involve the two existing suppliers in efforts to upgrade these seals were unsuccessful. Another suitable supplier had therefore to be found, and a 'new,' COG-owned seal developed; this was completed in 1997. This paper summarizes its testing, along with that of the two existing products. Resistance to aging has been improved significantly. Testing has shown that an accident can be safely withstood after 10 years of service or 40,000 openings-closings, whichever comes first. AECL's Fluid Sealing Technology Unit (FSTU) has invested in the special moulds, test fixtures and other necessary tooling and documentation required to begin commercial manufacture of this new quality product. Accordingly, as with FSTU's other nuclear products such as pump seals, the long-term supply of door seals to CANDU plants is now protected from many external uncertainties-e.g., commercial products being discontinued, materials being changed, companies going out of business. Manufacturing to AECL's detailed specifications is being subcontracted to the new supplier. FSTU is performing the quality surveillance, inspection, testing, and customer service activities concomitant with direct responsibility for supply to the plants. (author)

  6. Comparison of local transport studies with the profile consistency concept for ASDEX pellet-refuelled discharges

    International Nuclear Information System (INIS)

    Strongly peaked electron density profiles have been obtained in ASDEX by different refuelling methods: pellet fuelling, NBI counter-injection and recently by reduced gas puff fuelling scenarios. These discharges show in common increased density limits, a canonical electron temperature profile independent of the density profile and an improvement of the particle and energy confinement. Whereas the changes in particle transport are not fully understood, local transport analyses point out that the improved energy transport can be explained by reduced ion conduction losses coming close to the neoclassical ones. The different results for the ion transport with flat and peaked density profiles are quantitatively consistent with that expected from ηj-driven modes. So all cases showing confinement improvement through density peaking correspond to ηj and ηe) E with ηe for flat density profiles and the extension of the linear dependence for peaked ones in OH discharges then fits with a continuing inverse density dependence of the electron thermal diffusivity χe is also in agreement with τE enhancement when going from D+ to H+ ions. With additional heating χe is largely responsible for the confinement degradation in the L-mode and again the improvement at the H-mode transition. Near the plasma boundary χe is higher than χi in all cases investigated. (author). 9 refs, 7 figs

  7. Multi-channel Langmuir-probe and Hα-measurements of edge fluctuations on ASDEX

    International Nuclear Information System (INIS)

    The anomalous transport observed in tokamaks is caused by turbulent fluctuations, the nature of which is still poorly understood. Diagnostic difficulties are one major reason for this lack of understanding, at least with respect to the bulk plasma. The plasma edge, however, is accessible by several diagnostics permitting localized measurements of different parameters with good spatial and temporal resolution. For this reason one can hope to obtain enough information about edge fluctuations to permit the development of theoretical models. Different ranges of plasma parameters and the lack of closed magnetic surfaces distinguish this plasma zone from the bulk plasma. Edge turbulence might well involve other mechanisms than the turbulence in the bulk. Like in many limiter tokamaks Langmuir probes were used in the ASDEX divertor device for measurements of the floating potential and of the ion saturation current. Under certain assumptions the electron density and the plasma potential can be derived from these data. Observation of the Hα-light emitted from the edge in the vicinity of a neutral gas source yields information about the electron density. While probe measurements are more suitable for quantitative evaluations including the calculation of the local particle flux the Hα-method is not calibrated and integrates radially over the edge. It is however applicable in situations where probes fail because of excessive heat load. With 16-channel arrays both methods permit spatial correlations and wavenumber spectra to be determined without any further assumptions. (orig./AH)

  8. Impurity production and plasma performance in ASDEX discharges with ohmic and auxiliary heating

    Science.gov (United States)

    Fussmann, G.; ASDEX Team; NI Team; Icrh Team; Hofmann, J.; Janeschitz, G.; Lenoci, M.; Mast, F.; McCormick, K.; Murmann, H.; Poschenrieder, W.; Roth, J.; Setzensack, C.; Staudenmaier, G.; Steuer, K.-H.; Taglauer, E.; Verbeek, H.; Wagner, F.; Becker, G.; Bosch, H. S.; Brocken, H.; Eberhagen, A.; Gehre, O.; Gernhardt, J.; Gierke, G. V.; Clock, E.; Gruber, O.; Haas, G.; Izvozchikov, A.; Karger, F.; Kaufmann, M.; Keilhacker, M.; Klüber, O.; Kornherr, M.; Lackner, K.; Lisitano, G.; Mayer, H. M.; Meisel, D.; Mertens, V.; Müller, E. R.; Neuhauser, J.; Niedermeyer, H.; Noterdaeme, J.-M.; Pietrzyk, Z. A.; Rapp, H.; Riedler, H.; Röhr, H.; Ryter, F.; Schneider, F.; Siller, G.; Smeulders, P.; Söldner, F. X.; Speth, E.; Steinmetz, K.; Tsois, N.; Ugniewski, S.; Vollmer, O.; Wesner, F.; Zasche, D.

    1987-02-01

    A review is given on investigations in the ASDEX Tokamak on impurities in ohmically, NI and ICRH heated plasmas. For ohmic discharges in H 2 and D 2 it is found that iron release from the wall can be explained by sputtering due to neutral charge exchange (CX) atoms. In the case of He, however, significant contributions caused by ion sputtering are inferred. Comparing discharges with C limiters in He and D 2 suggests that in the case of hydrogen chemical processes are involved in C sputtering. By means of wall carbonization the concentrations of metal ions in the plasma could be substantially reduced. This achievement is of particular importance for NI counter-injection and ICRH, where under non-carbonized conditions severe impurity problems occur. We studied impurity confinement in the case of various heating scenarios by means of the laser injection technique. The poorest confinement is found for the L-phase of NI. Metal injection into the high confinement H-phase generally causes temporary suppression of the edge localized modes (ELM's). With respect to ICRH we conclude that enhanced wall erosion — probably due to the production of high energy ions in the boundary — together with a slightly increased impurity confinement is the dominant reason for the increase of the metallic concentrations. Impurity sputtering as an alternative strong erosion process was experimentally ruled out.

  9. Profile evaluation techniques for O-mode broadband microwave reflectometry on ASDEX

    International Nuclear Information System (INIS)

    Density profiles from reflectometry can be obtained, in principle, with phase or time delay measurements. In the first case frequency-modulated continuous waves (FM-CW) are launched into the plasma, and in the second one different types of signals, namely pulses, are used. Whereas in the ionosphere density profiles are normally obtained with pulsed radar techniques, in fusion plasmas FM-CW reflectometry has been mostly used. In both techniques the localization of each reflecting layer cannot be deducted from single measurements as, for the same measured phase shift or time delay, the location depends on the density of the plasma that the waves have encountered in their propagating path. So, in order to determine the correct position of each layer all the layers with lower densities have to be probed. As microwaves are very sensitive to plasma modes and broadband turbulence the resulting phase or time delay perturbations may lead to the incorrect interpretation of the data, causing large errors in the evaluated profiles. Also, in some cases, it is not possible to probe the complete plasma and deviations may occur due to the missing information. The evaluation of the profiles must, therefore, include data analysis procedures that take into account both the effect of plasma fluctuations and the limitations of the diagnostic. Here we present the techniques developed to analyse the ASDEX data, and discuss their potentialities for the routine evaluation of the density profiles from broadband reflectometry. (author). 3 refs, 12 figs

  10. User and Performance Impacts from Franklin Upgrades

    Energy Technology Data Exchange (ETDEWEB)

    He, Yun (Helen)

    2009-05-10

    The NERSC flagship computer Cray XT4 system"Franklin" has gone through three major upgrades: quad core upgrade, CLE 2.1 upgrade, and IO upgrade, during the past year. In this paper, we will discuss the various aspects of the user impacts such as user access, user environment, and user issues etc from these upgrades. The performance impacts on the kernel benchmarks and selected application benchmarks will also be presented.

  11. Regime of Improved Confinement and High Beta in Neutral-Beam-Heated Divertor Discharges of the ASDEX Tokamak

    Science.gov (United States)

    Wagner, F.; Becker, G.; Behringer, K.; Campbell, D.; Eberhagen, A.; Engelhardt, W.; Fussmann, G.; Gehre, O.; Gernhardt, J.; Gierke, G. V.; Haas, G.; Huang, M.; Karger, F.; Keilhacker, M.; Klüber, O.; Kornherr, M.; Lackner, K.; Lisitano, G.; Lister, G. G.; Mayer, H. M.; Meisel, D.; Müller, E. R.; Murmann, H.; Niedermeyer, H.; Poschenrieder, W.; Rapp, H.; Röhr, H.; Schneider, F.; Siller, G.; Speth, E.; Stäbler, A.; Steuer, K. H.; Venus, G.; Vollmer, O.; Yü, Z.

    1982-11-01

    A new operational regime has been observed in neutral-injection-heated ASDEX divertor discharges. This regime is characterized by high βp values comparable to the aspect ratio A (βp=1.9 MW, a mean density n¯e>=3×1013 cm-3, and a q(a) value >=2.6. Beyond these limits or in discharges with material limiter, low βp values and reduced particle and energy confinement times are obtained compared to the Ohmic heating phase.

  12. Processing options for bitumen upgrading

    International Nuclear Information System (INIS)

    It is estimated that 178 billion barrels of oil can be recovered from Alberta's vast heavy oil reserves. The challenge lies in the logistics of recovering, upgrading and transporting the oil to market. The Canadian Energy Research Institute conducted a recent study to determine market potential by 2007 for diluted bitumen and synthetic crude oil produced from upgraded bitumen. The viability for a wide range of bitumen feedstocks was assessed along with the sensitivity of refinery demand to their prices. The 3 major markets for western Canadian bitumen include PADD 2 in the United States, western Canada, and Ontario. Bitumen is too viscous to transport by pipeline and cannot be processed by most of the existing refineries. Therefore, in order to develop a mass market for the product, bitumen must undergo the energy intensive upgrading process at existing refineries. The factors impacting which method of upgrading is most suitable were discussed with particular attention to the impact that Canada's ratification of the Kyoto Protocol may have on Alberta's bitumen resource in terms of costs of complying with greenhouse gas reduction initiatives. The authors emphasized that it is crucial to customize an upgrading project to meet site and market specific factors. 8 refs., 3 tabs., 3 figs

  13. Project scenarios for bitumen upgrading

    International Nuclear Information System (INIS)

    The established reserves of Alberta's heavy oil resources are 178 billion barrels, and potential recoverable reserves are 315 billion barrels. The challenge of production includes the logistics of recovery, upgrading and transportation to market. Utilization of the bitumen is not simple because bitumen is too viscous to transport by pipeline. In addition, it is not processable by most existing refineries unless it can be upgraded through dilution. This paper examined different factors regarding the economic viability of various upgrading methods of a wide range of bitumen feedstocks. The study also examined the sensitivity of refinery demand to the prices of these feedstocks, along with the competitiveness among bitumen-based feedstock and conventional crudes. Western Canada, Ontario and the PADD II district in the United States are the 3 major markets for western Canadian bitumen based feedstock, the demand for which depends on refinery configurations and asphalt demand. This paper described the following 4 generic scenarios that describe Alberta bitumen upgrading projects: (1) adjacent to open pit mines, (2) adjacent to steam assisted gravity drainage (SAGD) facilities, (3) remotely located from resource production at an existing refinery, and (4) pipeline bitumen. It was noted that producers should determine the best way to upgrade the bitumen to ensure there is an economic market for the product, but they should also be aware not to over process the bitumen so as not to leave existing refinery facilities under-utilized. 2 refs., 1 tab., 3 figs

  14. The upgraded MAGIC Cherenkov telescopes

    Energy Technology Data Exchange (ETDEWEB)

    Tescaro, D., E-mail: dtescaro@iac.es [Instituto de Astrofísica de Canarias (IAC), E-38205 La Laguna, Tenerife (Spain); Universidad de La Laguna (ULL), Dept. Astrofísica, E-38206 La Laguna, Tenerife (Spain)

    2014-12-01

    The MAGIC Cherenkov telescopes underwent a major upgrade in 2011 and 2012. A new 1039-pixel camera and a larger area digital trigger system were installed in MAGIC-I, making it essentially identical to the newer MAGIC-II telescope. The readout systems of both telescopes were also upgraded, with fully programmable receiver boards and DRS4-chip-based digitization systems. The upgrade eased the operation and maintenance of the telescopes and also improved significantly their performance. The system has now an integral sensitivity as good as 0.6% of the Crab Nebula flux (for E>400GeV), with an effective analysis threshold at 70 GeV. This allows MAGIC to secure one of the leading roles among the current major ground-based Imaging Atmospheric Cherenkov telescopes for the next 5–10 years. - Highlights: • In 2011 and 2012 the MAGIC telescopes underwent a two-stage major upgrade. • The new camera of MAGIC-I allows us to exploit a 1.4 larger trigger area. • The novel DRS4-based readout systems allow a cost-effective ultra-fast digitization. • The upgrade greatly improved the maintainability of the system. • MAGIC has now an optimal integral sensitivity of 0.6% of the Crab Nebula flux.

  15. The upgraded MAGIC Cherenkov telescopes

    International Nuclear Information System (INIS)

    The MAGIC Cherenkov telescopes underwent a major upgrade in 2011 and 2012. A new 1039-pixel camera and a larger area digital trigger system were installed in MAGIC-I, making it essentially identical to the newer MAGIC-II telescope. The readout systems of both telescopes were also upgraded, with fully programmable receiver boards and DRS4-chip-based digitization systems. The upgrade eased the operation and maintenance of the telescopes and also improved significantly their performance. The system has now an integral sensitivity as good as 0.6% of the Crab Nebula flux (for E>400GeV), with an effective analysis threshold at 70 GeV. This allows MAGIC to secure one of the leading roles among the current major ground-based Imaging Atmospheric Cherenkov telescopes for the next 5–10 years. - Highlights: • In 2011 and 2012 the MAGIC telescopes underwent a two-stage major upgrade. • The new camera of MAGIC-I allows us to exploit a 1.4 larger trigger area. • The novel DRS4-based readout systems allow a cost-effective ultra-fast digitization. • The upgrade greatly improved the maintainability of the system. • MAGIC has now an optimal integral sensitivity of 0.6% of the Crab Nebula flux

  16. First operations with the new Collective Thomson Scattering diagnostic on the Frascati Tokamak Upgrade device

    Science.gov (United States)

    Bin, W.; Bruschi, A.; D'Arcangelo, O.; Castaldo, C.; De Angeli, M.; Figini, L.; Galperti, C.; Garavaglia, S.; Granucci, G.; Grosso, G.; Korsholm, S. B.; Lontano, M.; Mellera, V.; Minelli, D.; Moro, A.; Nardone, A.; Nielsen, S. K.; Rasmussen, J.; Simonetto, A.; Stejner, M.; Tartari, U.

    2015-10-01

    Anomalous emissions were found over the last few years in spectra of Collective Thomson Scattering (CTS) diagnostics in tokamak devices such as TEXTOR, ASDEX and FTU, in addition to real CTS signals. The signal frequency, down-shifted with respect to the probing one, suggested a possible origin in Parametric Decay Instability (PDI) processes correlated with the presence of magnetic islands and occurring for pumping wave power levels well below the threshold predicted by conventional models. A threshold below or close to the Electron Cyclotron Resonance Heating (ECRH) power levels could limit, under certain circumstances, the use of the ECRH in fusion devices. An accurate characterization of the conditions for the occurrence of this phenomenon and of its consequences is thus of primary importance. Exploiting the front-steering configuration available with the real-time launcher, the implementation of a new CTS setup now allows studying these anomalous emission phenomena in FTU under conditions of density and wave injection geometry that are more similar to those envisaged for CTS in ITER. The upgrades of the diagnostic are presented as well as a few preliminary spectra detected with the new system during the very first operations in 2014. The present work has been carried out under an EUROfusion Enabling Research project. A shorter version of this contribution is due to be published in PoS at: 1st EPS conference on Plasma Diagnostics

  17. First operations with the new Collective Thomson Scattering diagnostic on the Frascati Tokamak Upgrade device

    International Nuclear Information System (INIS)

    Anomalous emissions were found over the last few years in spectra of Collective Thomson Scattering (CTS) diagnostics in tokamak devices such as TEXTOR, ASDEX and FTU, in addition to real CTS signals. The signal frequency, down-shifted with respect to the probing one, suggested a possible origin in Parametric Decay Instability (PDI) processes correlated with the presence of magnetic islands and occurring for pumping wave power levels well below the threshold predicted by conventional models. A threshold below or close to the Electron Cyclotron Resonance Heating (ECRH) power levels could limit, under certain circumstances, the use of the ECRH in fusion devices. An accurate characterization of the conditions for the occurrence of this phenomenon and of its consequences is thus of primary importance. Exploiting the front-steering configuration available with the real-time launcher, the implementation of a new CTS setup now allows studying these anomalous emission phenomena in FTU under conditions of density and wave injection geometry that are more similar to those envisaged for CTS in ITER. The upgrades of the diagnostic are presented as well as a few preliminary spectra detected with the new system during the very first operations in 2014. The present work has been carried out under an EUROfusion Enabling Research project. A shorter version of this contribution is due to be published in PoS at: 1st EPS conference on Plasma Diagnostics

  18. Physical protection upgrades in Ukraine

    International Nuclear Information System (INIS)

    The U.S. DOE is providing nuclear material safeguards assistance in both material control and accountability and in physical protection to several facilities in Ukraine. This paper summarizes the types of physical protection upgrades that have been or are presently being implemented at these facilities. These facilities include the Kiev Institute for Nuclear Research, Kharkov Institute of Physics and Technology, Sevastopol Institute of Nuclear Energy and Industry, and the South Ukraine Nuclear Power Plant. Typical upgrades include: hardening of storage areas; improvements in access control, intrusion detection, and CCTV assessment; central alarm station improvements; and implementation of new voice communication systems. Methods used to implement these upgrades and problems encountered are discussed. Training issues are also discussed

  19. The D0 detector upgrade

    International Nuclear Information System (INIS)

    The Fermilab collider program is undergoing a major upgrade of both the accelerator complex and the two detectors. Operation of the Tevatron at luminosities upwards of ten time that currently provided will occur in early 1999 after the commissioning of the new Fermilab Main Injector. The D0 upgrade program has been established to deliver a detector that will meet the challenges of this environment. A new magnetic tracker consisting of a superconducting solenoid, a silicon vertex detector, a scintillating fiber central tracker, and a central preshower detector will replace the current central tracking and transition radiation chambers. We present the design and performance capabilities of these new systems and describe results from physics simulations that demonstrate the physics reach of the upgraded detector

  20. Environmental upgrading of a landfill

    International Nuclear Information System (INIS)

    This article refers to an experimental study concerning the vegetative upgrading of a closed-down landfill (once used for industrial waste disposal). The aim was to check the possibility of reconstructing or aiding the natural growth of a vegetation in keeping with the surrounding area, in a tried environment such as that of landfills. The original idea contained in the approved project - which meant to generically upgrade the territory by planting species belonging to the grassy layer, shrubs and trees - has, with time, undergone some changes. On the basis of both the knowledge acquired during management and of a more accurate analysis of the territory, the experiment was preferred to aim at finding out which were the species, both continental and Mediterranean, able to gradually adjust to the surrounding landscape, leaving to natural selection the task to decide which species were more suitable to the upgrading of closed-down landfills, and which planting technique was more effective

  1. Tank Farms Restoration and Upgrades Program Plan

    International Nuclear Information System (INIS)

    The Tank Farm Restoration and Upgrades Program Plan provides a summary description of action plans to renovate various Tank Farm management control programs, equipment, systems, and facilities. The Tank Farm upgrades identified in this plan are required (1) to ensure safe, environmentally compliant, and efficient operation of the facilities or (2) to support the waste cleanup mission at the Hanford Site. The program plan identifies planned Tank Farm upgrades through the Year 2000. This document summarizes the need basis (i.e., the justification) for planned upgrades and major uncertainties in upgrade planning. Summary-level schedules and interdependencies between projects and upgrade tasks are presented

  2. Upgrading the BEPC control system

    International Nuclear Information System (INIS)

    The BEPC control system has been put into operation and operated normally since the end of 1987. Three years's experience shows this system can satisfy basically the operation requirements, also exhibits some disadvantages araised from the original centralized system architecture based on the VAX-VCC-CAMAC, such as slow response, bottle neck of VCC, less CPU power for control etc.. This paper describes the method and procedure for upgrading the BEPC control system which will be based on DEC net and DEC-WS, and thus intend to upgrade the control system architecture from the centralized to the distributed and improve the integral system performance. (author)

  3. Multi-channel Langmuir-probe and Hα-measurements of edge fluctuations on ASDEX

    International Nuclear Information System (INIS)

    The anomalous transport observed in tokamaks is caused by turbulent fluctuations, the nature of which is still poorly understood. Diagnostic difficulties are one major reason for this lack of understanding, at least with respect to the bulk plasma. The plasma edge, however, is accessible by several diagnostics permitting localized measurements of different parameters with good spatial and temporal resolution. For this reason one can hope to obtain enough information about edge fluctuations to permit the development of theoretical models. Different ranges of plasma parameters and the lack of closed magnetic surfaces distinguish this plasma zone from the bulk plasma. Edge turbulence might well involve other mechanisms than the turbulence in the bulk. Although transport in the bulk plasma receives more attention transport in the edge plasma and edge physics are very relevant for reactor design. The realistic hope to find a solution and the importance of the problem for the next step in fusion research are reasons for the strong effort in this field on many tokamaks. Like in many limiter tokamaks Langmuir probes were used in the ASDEX divertor device for measurements of the floating potential and of the ion saturation current. Under certain assumptions the electron density and the plasma potential can be derived from these data. Observation of the Hα-light emitted from the edge in the vicinity of a neutral gas source yields information about the electron density. While probe measurements are more suitable for quantitative evaluations including the calculation of the local particle flux the Hα-method is not calibrated and integrates radially over the edge. It is however applicable in situations where probes fail because of excessive heat load. With 16-channel arrays both methods permit spatial correlations and wavenumber spectra to be determined without any further assumptions. (author) 4 refs., 2 figs

  4. Upgrade of the BATMAN test facility for H{sup −} source development

    Energy Technology Data Exchange (ETDEWEB)

    Heinemann, B., E-mail: bernd.heinemann@ipp.mpg.de; Fröschle, M.; Falter, H.-D.; Fantz, U.; Franzen, P.; Kraus, W.; Nocentini, R.; Riedl, R.; Ruf, B. [Max-Planck-Institut für Plasmaphysik, Boltzmannstr. 2, 85748 Garching (Germany)

    2015-04-08

    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.

  5. An invitation to critical mathematics education

    DEFF Research Database (Denmark)

    Skovsmose, Ole

    An Invitation to Critical Mathematics Education deals with a range of crucial topics. Among these are students’ foreground, landscapes of investigation, and mathematics in action. The book is intended for a broad audience: educators, students, teachers, policy makers, anybody interested in the...... further development of mathematics education. The book discusses concerns and preoccupation. This way it provides an invitation into critical mathematics education....

  6. The FNAL Injector Upgrade Status

    International Nuclear Information System (INIS)

    The new FNAL H- injector upgrade is currently being tested before installation in the Spring 2012 shutdown of the accelerator complex. This line consists of an H- source, low energy beam transport (LEBT), 200 MHz RFQ and medium energy beam transport (MEBT). Beam measurements have been performed to validate the design before installation. The results of the beam measurements are presented in this paper.

  7. Upgrading of the West Area

    CERN Multimedia

    1983-01-01

    The rejigged main hall (EHW1) in the West Area: on background, below the crane, is the brown yoke of the Omega magnet which had been resited. The upgrading was completed by the time in July when 400 GeV protons arrived. See Annual Report 1983 p. 107.

  8. Preparing the ALICE DAQ upgrade

    Science.gov (United States)

    Carena, F.; Carena, W.; Chapeland, S.; Chibante Barroso, V.; Costa, F.; Dénes, E.; Divià, R.; Fuchs, U.; Grigore, A.; Kiss, T.; Rauch, W.; Rubin, G.; Simonetti, G.; Soós, C.; Telesca, A.; Vande Vyvre, P.; Von Haller, B.

    2012-12-01

    In November 2009, after 15 years of design and installation, the ALICE experiment started to detect and record the first collisions produced by the LHC. It has been collecting hundreds of millions of events ever since with both proton and heavy ion collisions. The future scientific programme of ALICE has been refined following the first year of data taking. The physics targeted beyond 2018 will be the study of rare signals. Several detectors will be upgraded, modified, or replaced to prepare ALICE for future physics challenges. An upgrade of the triggering and readout systems is also required to accommodate the needs of the upgraded ALICE and to better select the data of the rare physics channels. The ALICE upgrade will have major implications in the detector electronics and controls, data acquisition, event triggering and offline computing and storage systems. Moreover, the experience accumulated during more than two years of operation has also lead to new requirements for the control software. We will review all these new needs and the current R&D activities to address them. Several papers of the same conference present in more details some elements of the ALICE online system.

  9. Upgrading of the Budapest reactor

    International Nuclear Information System (INIS)

    The increasing importance of neutron sources, high demand for irradiation and experimental facilities as well as improved safety requirements in the 'eighties, necessitate not only a technical modernization of the Reactor but an overall upgrade including instrumentation. Such a reconstruction was decided by the Hungarian governement in 1983

  10. The upgraded Pegasus Toroidal Experiment

    International Nuclear Information System (INIS)

    The Pegasus Toroidal Experiment was developed to explore the physics limits of plasma operation as the aspect ratio (A) approaches unity. Initial experiments on the device found that access to high normalized current and toroidal beta was limited by the presence of large-scale tearing modes. Major upgrades have been conducted of the facility to provide the control tools necessary to mitigate these resistive modes. The upgrades include new programmable power supplies, new poloidal field coils and increased, time-variable toroidal field. First ohmic operations with the upgraded system demonstrated position and current ramp-rate control, as well as improvement in ohmic flux consumption from 2.9 MA Wb-1 to 4.2 MA Wb-1. The upgraded experiment will be used to address three areas of physics interest. First, the kink and ballooning stability boundaries at low A and high normalized current will be investigated. Second, clean, high-current plasma sources will be studied as a helicity injection tool. Experiments with two such sources have produced toroidal currents three times greater than predicted by geometric field line following. Finally, the use of electron Bernstein waves to heat and drive current locally will be studied at the 1 MW level; initial modelling indicates that these experiments are feasible at a frequency of 2.45 GHz

  11. The upgradation of Aditya Tokamak

    International Nuclear Information System (INIS)

    Aditya Tokamak is the first Indian tokamak, indigenously built and commissioned at the Institute for Plasma Research, Gandhinagar, Gujarat, India, in September, 1989. Aditya Tokamak has been in operation since more than 25 years. More than 30,000 discharges are taken and a large number of experiments are carried out, with plasma current ranging from 50 KA to 150 KA, lasting for 100 to 250 milliseconds. Various types of wall conditioning techniques and different hot plasma diagnostics are tested and operated on Aditya Tokamak. The experiments for turbulent particle transport and turbulence in the edge plasma, gas puffing, lithium coating, mitigation, plasma disruption, limiter and electron biasing, runaway discharges etc. led to many interesting results contributing immensely to the world of thermonuclear fusion. Experiments on Pre-ionization and Plasma heating by ICRH and ECRH are also worked out. The scientific objectives of Aditya tokamak Upgrade include Low loop voltage plasma start-up with strong pre-ionization having a good plasma control system. The upgrade is designed keeping in mind the experiments, disruption mitigation studies relevant to future fusion devices, runway mitigation studies, demonstration of Radio-frequency heating and current drive etc. This upgraded Aditya tokamak will be used for basic studies on plasma confinement and scaling to larger devices, development and testing of new diagnostics etc. This machine will be easily accessible compared to SST-1 and will be very useful for generation of technical and scientific expertise for future fusion devices. In this paper, especial features of the upgrade including various aspects of designing of new components for Aditya Upgrade tokamak is presented

  12. EMC3-Eirene simulations of particle- and energy fluxes to main chamber- and divertor plasma facing components in ASDEX Upgrade compared to experiments

    Science.gov (United States)

    Lunt, T.; Carralero, D.; Feng, Y.; Birkenmeier, G.; Müller, H. W.; Müller, S.; Wischmeier, M.

    2015-08-01

    We report on first EMC3-Eirene simulations with an extended computational grid including both divertor- and main chamber (MC) 3D wall plasma-facing components (PFCs). In a first step we compare the simulations to low-power L-mode discharges systematically analyzed by Carralero et al., who observed a transition from a low- to a high density regime (Carralero et al., 2014). Case A is a configuration at low density and high clearance, while B is a high density regime configuration at medium clearance. In order to explain the upstream far-SOL ne profiles of B the MC PFCs and an enhanced transport region at ρ = 1.01, …, 1.03 need to be included in the simulations. In a second step we compute the particle-, and power fluxes to the limiter for the realistic geometry, for limiters displaced radially inward and for a toroidally symmetric limiter. Almost the same fraction of power as that to the divertor is absorbed by the MC PFCs in the simulation of case B.

  13. Take control of upgrading to Leopard

    CERN Document Server

    Kissell, Joe

    2009-01-01

    Start on the right foot with Mac OS X 10.5 Leopard! Little is more exciting and unnerving than a major operating system upgrade for your Mac, but thousands of people have upgraded to Panther and Tiger calmly and successfully with the advice in Joe Kissell's previous hit Take Control of Upgrading... titles. Joe's expert guidance, developed over innumerable test installations, walks you through the six steps necessary before upgrading, which of Leopard's three installation options is right for you, how to perform the actual upgrade, and post-installation checking and cleanup.

  14. MIPP Plastic Ball electronics upgrade

    International Nuclear Information System (INIS)

    An upgrade electronics design for Plastic Ball detector is described. The Plastic Ball detector was a part of several experiments in the past and its back portion (proposed to be used in MIPP) consists of 340 photomultipliers equipped with a sandwich scintillator. The scintillator sandwich has fast and slow signal component with decay times 10 ns and 1 (micro)s respectively. The upgraded MIPP experiment will collect up to 12,000 events during each 4 second spill and read them out in ∼50 seconds between spills. The MIPP data acquisition system will employ deadtime-less concept successfully implemented in Muon Electronics of Dzero experiment at Fermilab. An 8-channel prototype design of the Plastic Ball Front End (PBFE) implementing these requirements is discussed. Details of the schematic design, simulation and prototype test results are discussed.

  15. MIPP Plastic Ball electronics upgrade

    International Nuclear Information System (INIS)

    An upgrade electronics design for Plastic Ball detector is described. The Plastic Ball detector was a part of several experiments in the past and its back portion (proposed to be used in Main Injector Particle Production (MIPP)) consists of 340 photomultipliers equipped with a sandwich scintillator. The scintillator sandwich has fast and slow signal component with decay times 10 ns and 1 μs, respectively. The upgraded MIPP experiment will collect up to 12,000 events during each 4 s spill and read them out in ∼50 s between spills. The MIPP data acquisition system will employ deadtime-less concept successfully implemented in Muon Electronics of Dzero experiment at Fermilab An 8-channel prototype design of the Plastic Ball Front-End (PBFE) implementing these requirements is discussed. Details of the schematic design, simulation and prototype test results are discussed.

  16. Fermilab Booster Correction Elements upgrade

    International Nuclear Information System (INIS)

    The Fermilab Booster Correction Element Power Supply System is being upgraded to provide significant improvements in performance and versatility. At the same time these improvements will compliment raising the Booster injection energy from 200 MeV to 400 MeV and will allow increased range of adjustment to tune, chromaticity, closed orbit and harmonic corrections. All correction elements will be capable of ramping to give dynamic orbit, tune and chromaticity control throughout the acceleration cycle. The power supplies are commercial switch mode current sources capable of operating in all four current-voltage quadrants. External secondary feedback loops on the amplifiers have extended the small signal bandwidth to 3 kHz and allow current ramps in excess of 1000 A/sec. Implementation and present status of the upgrade project is described in this paper. (author) 4 refs., 2 figs., 1 tab

  17. Upgraded wood residue fuels 1995

    International Nuclear Information System (INIS)

    The Swedish market for upgraded residue fuels, i.e. briquettes, pellets and wood powder, has developed considerably during the nineties. The additional costs for the upgrading processes are regained and create a surplus in other parts of the system, e.g. in the form of higher combustion efficiencies, lower investment costs for burning equipment, lower operation costs and a diminished environmental impact. All these factors put together have resulted in a rapid growth of this part of the energy sector. In 1994 the production was 1.9 TWh, an increase of 37 % compared to the previous year. In the forthcoming heating season 1995/96 the production may reach 4 TWh. 57 refs, 11 figs, 6 tabs

  18. B physics with upgraded detector

    CERN Document Server

    Palla, Fabrizio

    2016-01-01

    The CMS potential for B-Physics with the Upgraded Phase-I and Phase-II detectors will be discussed, with the $\\mathrm{B}_{s}^{0}\\to\\mu^{+}\\mu^{-}$ and $\\mathrm{B}^{0}\\to\\mu^{+}\\mu^{-}$ benchmark channels, for the runs of the LHC at $\\sqrt{s}=14$~TeV up to an integrated luminosity of 3000~$\\mathrm{fb}^{-1}$. With the upgraded CMS detector it will be possible to efficiently trigger and reconstruct both processes, with reduced statistical and systematic uncertainties leading to high precision measurements of the branching fractions of the $\\mathrm{B}^{0}\\to\\mu^{+}\\mu^{-}$ and $\\mathrm{B}_{s}^{0}\\to\\mu^{+}\\mu^{-}$ decays. This will allow in turn stringent tests of the Standard Model.

  19. Tevatron Beam Position Monitor Upgrade

    CERN Document Server

    Wolbers, Stephen; Barker, B; Bledsoe, S; Boes, T; Bowden, Mark; Cancelo, Gugstavo I; Dürling, G; Forster, B; Haynes, B; Hendricks, B; Kasza, T; Kutschke, Robert K; Mahlum, R; Martens, Michael A; Mengel, M; Olsen, M; Pavlicek, V; Pham, T; Piccoli, Luciano; Steimel, Jim; Treptow, K; Votava, Margaret; Webber, Robert C; West, B; Zhang, D

    2005-01-01

    The Tevatron Beam Position Monitor (BPM) readout electronics and software have been upgraded to improve measurement precision, functionality and reliability. The original system, designed and built in the early 1980s, became inadequate for current and future operations of the Tevatron. The upgraded system consists of 960 channels of new electronics to process analog signals from 240 BPMs, new front-end software, new online and controls software, and modified applications to take advantage of the improved measurements and support the new functionality. The new system reads signals from both ends of the existing directional stripline pickups to provide simultaneous proton and antiproton position measurements. Measurements using the new system are presented that demonstrate its improved resolution and overall performance.

  20. CMS upgrade and future plans

    OpenAIRE

    Hoepfner Kerstin

    2015-01-01

    CMS plans for operation at the LHC phase-II unprecedented in terms of luminosity thus resulting in serious consequences for detector performance. To achieve the goal to maintain the present excellent performance of the CMS detector, several upgrades are necessary. To handle the high phase-II data rates, the readout and trigger systems are redesigned using recent technology developments. The high particle rates will accelerate detector aging and require replacement of the tracker and forward c...

  1. The FNAL Injector Upgrade Status

    Energy Technology Data Exchange (ETDEWEB)

    Tan, C.Y.; Bollinger, D.S.; Duel, K.L.; Karns, P.R.; Lackey, J.R.; Pellico, W.A; Scarpine, V.E.; Tomlin, R.E.; /Fermilab

    2012-05-14

    The new FNAL H{sup -} injector upgrade is currently being tested before installation in the Spring 2012 shutdown of the accelerator complex. This line consists of an H{sup -} source, low energy beam transport (LEBT), 200 MHz RFQ and medium energy beam transport (MEBT). Beam measurements have been performed to validate the design before installation. The results of the beam measurements are presented in this paper.

  2. AliPDU Package Upgrade

    CERN Document Server

    "Martin, Michael

    2015-01-01

    "AliPDU Package" is a set of script, panels, and datapoints designed in WinCC to manage and monitor PDU's. PDU is an essential component in the data center, in order to make data center working properly through the monitoring of power distribution and environmental condition of the data center. In this project "AliPDU Package" is upgraded so it can be used to monitor environmental condition of data center using PDU's and external environmental sensor connected to PDU.

  3. AliPDU Package Upgrade

    CERN Document Server

    Martin, Michael

    2015-01-01

    AliPDU Package is a set of script, panels, and datapoints designed in WinCC to manage and monitor PDU's. PDU is an essential component in the data center, in order to make data center working properly through the monitoring of power distribution and environmental condition of the data center. In this project "AliPDU Package" is upgraded so it can be used to monitor environmental condition of data center using PDU's and external environmental sensor connected to PDU.

  4. Upgrading the NRU research reactor

    International Nuclear Information System (INIS)

    After a nearly two-year long detailed review, AECL Research decided that its NRU research reactor will complete its mission around the turn of the century. The company's original intentions for major refurbishment have been revised and upgrading work will now mainly comprise add-ons to existing systems - so that research projects and isotope production schedules can be met - and procedure modifications to ensure continued safe operation. (Author)

  5. RHIC and its upgrade programmes.

    Energy Technology Data Exchange (ETDEWEB)

    Roser,T.

    2008-06-23

    As the first hadron accelerator and collider consisting of two independent superconducting rings RHIC has operated with a wide range of beam energies and particle species. After a brief review of the achieved performance the presentation will give an overview of the plans, challenges and status of machine upgrades, that range from a new heavy ion pre-injector and beam cooling at 100 GeV to a high luminosity electron-ion collider.

  6. Conclusion. Upgrading the marketing function

    OpenAIRE

    Lambin, Jean-Jacques

    2013-01-01

    More countries, more customer segments, more distribution channels, more direct and substitute competitors, new market actors, new communication technologies, new virtual market places, fast changing technologies, new media controlled by consumers, new civil society stakeholders, … The growing complexity of the global market has numerous causes. To cope with this increased complexity, the firm has to redefine the way the marketing function operates by broadening and upgrading its role, by cha...

  7. 48 CFR 14.209 - Cancellation of invitations before opening.

    Science.gov (United States)

    2010-10-01

    ... REGULATION CONTRACTING METHODS AND CONTRACT TYPES SEALED BIDDING Solicitation of Bids 14.209 Cancellation of... invitation is desirable. (b) When an invitation issued other than electronically is cancelled, bids that have... prospective bidders to whom invitations were issued. When an invitation issued electronically is cancelled,...

  8. The Pegasus-Upgrade Experiment

    Science.gov (United States)

    Fonck, R. J.; Bongard, M. W.; Barr, J. L.; Frerichs, H. G.; Lewicki, B. T.; Reusch, J. A.; Schmitz, O.; Winz, G. R.

    2015-11-01

    Tokamak operation at near-unity aspect ratio provides access to advanced tokamak physics at modest parameters. High plasma current is accessible at very low toroidal field. This offers H-mode performance at Te levels that allow use of electrostatic and magnetic probe arrays through the edge pedestal region into the plasma core. An upgrade to the Pegasus ST is planned to exploit these features and pursue unique studies in three areas: local measurements of pedestal and ELM dynamics at Alfvenic timescales; direct measurement of the local plasma response to application of 3D magnetic perturbations with high spectral flexibility; and extension of Local Helicity Injection for nonsolenoidal startup to NSTX-U-relevant confinement and stability regimes. Significant but relatively low-cost upgrades to the facility are proposed: a new centerstack with larger solenoid and 2x the number of toroidal field conductors; a new TF power supply and conversion of the 200 MVA OH power supply to a cascaded multilevel inverter configuration; and installation of an extensive 3D-magnetic perturbation coil system for ELM mitigation and suppression studies. The upgraded facility will provide 0.3 MA plasmas with pulse lengths of 50-100 msec flattop, aspect ratio <1.25, and toroidal field up to 0.4 T. These research activities will be integrated into related efforts on DIII-D and NSTX-U. Work supported by US DOE grant DE-FG02-96ER54375.

  9. SLHC: The LHC luminosity upgrade

    International Nuclear Information System (INIS)

    The LHC will provide unprecedented sensitivity to Standard Model and beyond the Standard Model Physics. However, some important Standard Model measurements as well as a wide part of the spectrum of particles predicted by many promising theoretical models of New Physics are likely beyond the LHC reach. For such observations, a factor-of-ten increase in LHC statistics will have a major impact. A luminosity upgrade is therefore planned for the LHC. The SLHC as well as offering the possibility to increase the Physics potential will create an extreme operating environment for the detectors, particularly the tracking devices. An increase in the number of minimum bias events per beam crossing by at least an order of magnitude beyond the levels envisioned for LHC design luminosity creates the need to handle much higher occupancies and for the innermost layers unprecedented levels of radiation. This will require a fully upgraded tracking system giving a higher granularity, while trying not to exceed the material budget and power levels of the current trackers. The much higher rate of interactions may also push the limits of the Level-1 trigger system. Efforts have already begun to address these issues. This paper presents the possible Physics reaches at SLHC and the current understanding of what systems will need to be upgraded.

  10. Reflectometry measurements of the m=1 satellite mode in L- and H-mode plasmas in ASDEX

    International Nuclear Information System (INIS)

    In ASDEX, with strong NBI heating, often a large central m=1, n=1 mode is observed on the SXR emission. For PNBI ≥ 1 MW a mode rotating with the same frequency, the so-called 'm=1 satellite', is seen on the magnetic pick-up coils in the L and H-phases. Magnetic measurements in the divertor chamber suggest that the satellite mode might be located outside the separatrix, on open field lines reaching the divertor. Here we present results from localized microwave reflectometric measurements. The time evolution of the satellite mode frequency is studied for plasmas with different qa and the mode localization is estimated, confirming that it should be close to but outside the separatrix. The central toroidal rotation velocities of the plasma can be inferred from the measured frequencies of the satellite modes. (orig.)

  11. CMS upgrade and future plans

    Directory of Open Access Journals (Sweden)

    Hoepfner Kerstin

    2015-01-01

    Full Text Available CMS plans for operation at the LHC phase-II unprecedented in terms of luminosity thus resulting in serious consequences for detector performance. To achieve the goal to maintain the present excellent performance of the CMS detector, several upgrades are necessary. To handle the high phase-II data rates, the readout and trigger systems are redesigned using recent technology developments. The high particle rates will accelerate detector aging and require replacement of the tracker and forward calorimeters. In addition, the muon system will be extended.

  12. The Upgraded D0 detector

    Energy Technology Data Exchange (ETDEWEB)

    Abazov, V.M.; Abbott, B.; Abolins, M.; Acharya, B.S.; Adams, D.L.; Adams, M.; Adams, T.; Agelou, M.; Agram, J.-L.; Ahmed, S.N.; Ahn, S.H.; Ahsan, M.; Alexeev, G.D.; Alkhazov, G.; Alton, A.; Alverson, G.; Alves, G.A.; Anastasoaie, M.; Andeen, T.; Anderson, J.T.; Anderson, S.; /Buenos Aires U. /Rio de Janeiro, CBPF /Sao Paulo, IFT /Alberta U.

    2005-07-01

    The D0 experiment enjoyed a very successful data-collection run at the Fermilab Tevatron collider between 1992 and 1996. Since then, the detector has been upgraded to take advantage of improvements to the Tevatron and to enhance its physics capabilities. We describe the new elements of the detector, including the silicon microstrip tracker, central fiber tracker, solenoidal magnet, preshower detectors, forward muon detector, and forward proton detector. The uranium/liquid-argon calorimeters and central muon detector, remaining from Run I, are discussed briefly. We also present the associated electronics, triggering, and data acquisition systems, along with the design and implementation of software specific to D0.

  13. VISIR upgrade overview and status

    Science.gov (United States)

    Kerber, Florian; Käufl, Hans-Ulrich; Baksai, Pedro; Di Lieto, Nicola; Dobrzycka, Danuta; Duhoux, Philippe; Finger, Gert; Heikamp, Stephanie; Ives, Derek; Jakob, Gerd; Lundin, Lars; Mawet, Dimitri; Mehrgan, Leander; Momany, Yazan; Moreau, Vincent; Pantin, Eric; Riquelme, Miguel; Sandrock, Stefan; Siebenmorgen, Ralf; Smette, Alain; Taylor, Julian; van den Ancker, Mario; Valdes, Guillermo; Venema, Lars; Weilenmann, Ueli

    2014-07-01

    We present an overview of the VISIR upgrade project. VISIR is the mid-infrared imager and spectrograph at ESO's VLT. The project team is comprised of ESO staff and members of the original VISIR consortium: CEA Saclay and ASTRON. The project plan is based on input from the ESO user community with the goal of enhancing the scientific performance and efficiency of VISIR by a combination of measures: installation of improved hardware, optimization of instrument operations and software support. The cornerstone of the upgrade is the 1k by 1k Si:As AQUARIUS detector array (Raytheon) which has been carefully characterized in ESO's IR detector test facility (modified TIMMI 2 instrument). A prism spectroscopic mode will cover the N-band in a single observation. New scientific capabilities for high resolution and high-contrast imaging will be offered by sub-aperture mask (SAM) and phase-mask coronagraphic (4QPM/AGPM) modes. In order to make optimal use of favourable atmospheric conditions a water vapour monitor has been deployed on Paranal, allowing for real-time decisions and the introduction of a user-defined constraint on water vapour. During the commissioning in 2012 it was found that the on-sky sensitivity of the AQUARIUS detector was significantly below expectations and that VISIR was not ready to go back to science operations. Extensive testing of the detector arrays in the laboratory and on-sky enabled us to diagnose the cause for the shortcoming of the detector as excess low frequency noise (ELFN). It is inherent to the design chosen for this detector and can't be remedied by changing the detector set-up. Since this is a form of correlated noise its impact can be limited by modulating the scene recorded by the detector. We have studied several mitigation options and found that faster chopping using the secondary mirror (M2) of the VLT offers the most promising way forward. Faster M2 chopping has been tested and is scheduled for implementation before the end of 2014

  14. The Upgraded D0 Detector

    CERN Document Server

    Abazov, V M; Abolins, M; Acharya, B S; Adams, D L; Adams, M; Adams, T; Agelou, M; Agram, J L; Ahmed, S N; Ahn, S H; Ahsan, M; Alexeev, G D; Alkhazov, G; Alton, A; Alverson, G; Alves, G A; Anastasoaie, M; Andeen, T; Anderson, J T; Anderson, S; Andrieu, B; Angstadt, R; Anosov, V; Arnoud, Y; Arov, M; Askew, A; Åsman, B; Assis-Jesus, A C S; Atramentov, O; Autermann, C; Avila, C; Babukhadia, L; Bacon, Trevor C; Badaud, F; Baden, A; Baffioni, S; Bagby, L; Baldin, B; Balm, P W; Banerjee, P; Banerjee, S; Barberis, E; Bardon, O; Barg, W; Bargassa, P; Baringer, P; Barnes, C; Barreto, J; Bartlett, J F; Bassler, U; Bhattacharjee, M; Baturitsky, M A; Bauer, D; Bean, A; Baumbaugh, B; Beauceron, S; Begalli, M; Beaudette, F; Begel, M; Bellavance, A; Beri, S B; Bernardi, G; Bernhard, R; Bertram, I; Besançon, M; Besson, A; Beuselinck, R; Beutel, D; Bezzubov, V A; Bhat, P C; Bhatnagar, V; Binder, M; Biscarat, C; Bishoff, A; Black, K M; Blackler, I; Blazey, G; Blekman, F; Blessing, S; Bloch, D; Blumenschein, U; Bockenthein, E; Bodyagin, V; Böhnlein, A; Boeriu, O; Bolton, T A; Bonamy, P; Bonifas, D; Borcherding, F; Borissov, G; Bos, K; Bose, T; Boswell, C; Bowden, M; Brandt, A; Briskin, G; Brock, R; Brooijmans, G; Bross, A; Buchanan, N J; Buchholz, D; Bühler, M; Büscher, V; Burdin, S; Burke, S; Burnett, T H; Busato, E; Buszello, C P; Butler, D; Butler, J M; Cammin, J; Caron, S; Bystrický, J; Canal, L; Canelli, F; Carvalho, W; Casey, B C K; Casey, D; Cason, N M; Castilla-Valdez, H; Chakrabarti, S; Chakraborty, D; Chan, K M; Chandra, A; Chapin, D; Charles, F; Cheu, E; Chevalier, L; Chi, E; Chiche, R; Cho, D K; Choate, R; Choi, S; Choudhary, B; Chopra, S; Christenson, J H; Christiansen, T; Christofek, L; Churin, I; Cisko, G; Claes, D; Clark, A R; Clement, B; Clément, C; Coadou, Y; Colling, D J; Coney, L; Connolly, B; Cooke, M; Cooper, W E; Coppage, D; Corcoran, M; Coss, J; Cothenet, A; Cousinou, M C; Cox, B; Crepe-Renaudin, S; Cristetiu, M; Cummings, M A C; Cutts, D; Da Motta, H; Das, M; Davies, B; Davies, G; Davis, G A; Davis, W; De, K; de Jong, P; De Jong, S J; De La Cruz-Burelo, E; de La Taille, C; De Oliveira Martins, C; Dean, S; Degenhardt, J D; Déliot, F; Delsart, P A; Del Signore, K; De Maat, R; Demarteau, M; Demina, R; Demine, P; Denisov, D; Denisov, S P; Desai, S; Diehl, H T; Diesburg, M; Doets, M; Doidge, M; Dong, H; Doulas, S; Dudko, L V; Duflot, L; Dugad, S R; Duperrin, A; Dvornikov, O; Dyer, J; Dyshkant, A; Eads, M; Edmunds, D; Edwards, T; Ellison, J; Elmsheuser, J; Eltzroth, J T; Elvira, V D; Eno, S; Ermolov, P; Eroshin, O V; Estrada, J; Evans, D; Evans, H; Evdokimov, A; Evdokimov, V N; Fagan, J; Fast, J; Fatakia, S N; Fein, D; Feligioni, L; Ferapontov, A V; Ferbel, T; Ferreira, M J; Fiedler, F; Filthaut, F; Fisher, W; Fisk, H E; Fleck, I; Fitzpatrick, T; Flattum, E; Fleuret, F; Flores, R; Foglesong, J; Fortner, M; Fox, H; Franklin, C; Freeman, W; Fu, S; Fuess, S; Gadfort, T; Galea, C F; Gallas, E; Galyaev, E; Gao, M; García, C; García-Bellido, A; Gardner, J; Gavrilov, V; Gay, A; Gay, P; Gelé, D; Gelhaus, R; Genser, K; Gerber, C E; Gershtein, Yu; Gillberg, D; Geurkov, G; Ginther, G; Gobbi, B; Goldmann, K; Golling, T; Gollub, N; Golovtsov, V L; Gómez, B; Gómez, G; Gómez, R; Goodwin, R W; Gornushkin, Y; Gounder, K; Goussiou, A; Graham, D; Graham, G; Grannis, P D; Gray, K; Greder, S; Green, D R; Green, J; Green, J A; Greenlee, H; Greenwood, Z D; Gregores, E M; Grinstein, S; Gris, P; Grivaz, J F; Groer, L; Grünendahl, S; Grünewald, M W; Gu, W; Guglielmo, J; Sen-Gupta, A; Gurzhev, S N; Gutíerrez, G; Gutíerrez, P; Haas, A; Hadley, N J; Haggard, E; Haggerty, H; Hagopian, S; Hall, I; Hall, R E; Han, C; Han, L; Hance, R; Hanagaki, K; Hanlet, P; Hansen, S; Harder, K; Harel, A; Harrington, R; Hauptman, J M; Hauser, R; Hays, C; Hays, J; Hazen, E; Hebbeker, T; Hebert, C; Hedin, D; Heinmiller, J M; Heinson, A P; Heintz, U; Hensel, C; Hesketh, G; Hildreth, M D; Hirosky, R; Hobbs, J D; Hoeneisen, B; Hohlfeld, M; Hong, S J; Hooper, R; Hou, S; Houben, P; Hu, Y; Huang, J; Huang, Y; Hynek, V; Huffman, D; Iashvili, I; Illingworth, R; Ito, A S; Jabeen, S; Jacquier, Y; Jaffré, M; Jain, S; Jain, V; Jakobs, K; Jayanti, R; Jenkins, A; Jesik, R; Jiang, Y; Johns, K; Johnson, M; Johnson, P; Jonckheere, A; Jonsson, P; Jöstlein, H; Jouravlev, N I; Juárez, M; Juste, A; Kaan, A P; Kado, M; Käfer, D; Kahl, W; Kahn, S; Kajfasz, E; Kalinin, A M; Kalk, J; Kalmani, S D; Karmanov, D; Kasper, J; Katsanos, I; Kau, D; Kaur, R; Ke, Z; Kehoe, R; Kermiche, S; Kesisoglou, S; Khanov, A; Kharchilava, A I; Kharzheev, Yu M; Kim, H; Kim, K H; Kim, T J; Kirsch, N; Klima, B; Klute, M; Kohli, J M; Konrath, J P; Komissarov, E V; Kopal, M; Korablev, V M; Kostritskii, A V; Kotcher, J; Kothari, B; Kotwal, A V; Koubarovsky, A; Kozelov, A V; Kozminski, J; Kryemadhi, A; Kuznetsov, O; Krane, J; Kravchuk, N; Krempetz, K; Krider, J; Krishnaswamy, M R

    2005-01-01

    The D0 experiment enjoyed a very successful data-collection run at the Fermilab Tevatron collider between 1992 and 1996. Since then, the detector has been upgraded to take advantage of improvements to the Tevatron and to enhance its physics capabilities. We describe the new elements of the detector, including the silicon microstrip tracker, central fiber tracker, solenoidal magnet, preshower detectors, forward muon detector, and forward proton detector. The uranium/liquid-argon calorimeters and central muon detector, remaining from Run I, are discussed briefly. We also present the associated electronics, triggering, and data acquisition systems, along with the design and implementation of software specific to D0.

  15. Proposal for the award of a contract, without competitive tendering, for the supply and upgrade of positioning sensors for the LHC

    CERN Document Server

    2004-01-01

    This document concerns the award of a contract, without competitive tendering, for the supply of 60 new Hydrostatic Leveling Systems (HLS sensors) and 25 new Wire Positioning Systems (WPS sensors) and for the upgrade of 63 existing sensors. For the reasons explained in this document, the Finance Committee is invited to agree to the negotiation of a contract with FOGALE NANOTECH (FR), for the supply and upgrade of HLS and WPS sensors for a total amount of 412 913 euros (631 757 Swiss francs), not subject to revision. The amount in Swiss francs has been calculated using the present rate of exchange.

  16. Upgrading Status Of Bandung Triga 2000 Reactor

    International Nuclear Information System (INIS)

    Upgrading Status Of Bandung TRIGA 2000 Reactor. Upgrading of TRIGA Mark II Reactor from 1000 k W to 2000 k W has been done. On June 24, 2000 it has been inaugurated by the Vice President, Madame Megawati Soekarnoputri. The solution of the problems faced in the upgrading should be described here since some experiences got during the process probably are very useful, especially the methods in finishing the project

  17. Pipeline transportation of emerging partially upgraded bitumen

    International Nuclear Information System (INIS)

    The recoverable reserves of Canada's vast oil deposits is estimated to be 335 billion barrels (bbl), most of which are in the Alberta oil sands. Canada was the largest import supplier of crude oil to the United States in 2001, followed by Saudi Arabia. By 2011, the production of oil sands is expected to increase to 50 per cent of Canada's oil, and conventional oil production will decline as more production will be provided by synthetic light oil and bitumen. This paper lists the announced oil sands projects. If all are to proceed, production would reach 3,445,000 bbl per day by 2011. The three main challenges regarding the transportation and marketing of this new production were described. The first is to expand the physical capacity of existing pipelines. The second is the supply of low viscosity diluent (such as natural gas condensate or synthetic diluent) to reduce the viscosity and density of the bitumen as it passes through the pipelines. The current pipeline specifications and procedures to transport partially upgraded products are presented. The final challenge is the projected refinery market constraint to process the bitumen and synthetic light oil into consumer fuel products. These challenges can be addressed by modifying refineries and increasing Canadian access in Petroleum Administration Defense District (PADD) II and IV. The technology for partial upgrading of bitumen to produce pipeline specification oil, reduce diluent requirements and add sales value, is currently under development. The number of existing refineries to potentially accept partially upgraded product is listed. The partially upgraded bitumen will be in demand for additional upgrading to end user products, and new opportunities will be presented as additional pipeline capacity is made available to transport crude to U.S. markets and overseas. The paper describes the following emerging partial upgrading methods: the OrCrude upgrading process, rapid thermal processing, CPJ process for

  18. BNFL Magnox - Upgrades and enhancements

    International Nuclear Information System (INIS)

    In the past, generic models, restrictive budgets,and general shortages of resources have limited the scope of the UK's older Magnox simulators. Nevertheless, the simulators evolved slowly over time, becoming more like their reference plants, as resources became available. Three years ago, the Training and Development Branch of Magnox Electric plc took a giant leap, investing significant resources into the modernization of their training simulators. New hardware was built, including a new simulator room. The simulator software was ported from Unix running on outdated servers to new servers running Microsoft Windows NT. Perhaps most significantly, major model enhancements were made to key plant systems to significantly increase the likeness of each simulator to its reference plant. The upgrade to NT, the addition of state-of-the-art instructor stations, and some of the model enhancements were achieved with SimPort, an all-inclusive simulation package provided by DS and S. This paper will provide a more detailed view of the Magnox modular simulators, including how they are used and how they have benefited from the enhancements and upgrades implemented during the project. (author)

  19. ALICE upgrades its powerful eyes

    CERN Multimedia

    Yuri Kharlov, ALICE Collaboration

    2013-01-01

    The ALICE Photon Spectrometer (PHOS) is a high-resolution photon detector that measures the photons coming out of the extremely hot plasma created in the lead-lead collisions at the LHC. Taking advantage of the long accelerator shut-down, the ALICE teams are now repairing and upgrading the existing modules and getting ready to install the brand-new module in time for the next run. The upgraded PHOS detector will be faster and more stable with wider acceptance and improved photon identification.   PHOS crystal matrix during repair. The key feature and the main complexity of the ALICE PHOS detector is that it operates at a temperature of -25°C, which makes it the second-coldest equipment element at the LHC after the cryogenic superconducting magnets. Since 2009 when it was installed, the PHOS detector, with its cold and warm volumes, has been immersed in airtight boxes to avoid condensation in the cold volumes. The 10,752 lead tungstate crystals of the PHOS were completely insulated fr...

  20. Analysis Efforts Supporting NSTX Upgrades

    International Nuclear Information System (INIS)

    The National Spherical Torus Experiment (NSTX) is a low aspect ratio, spherical torus (ST) configuration device which is located at Princeton Plasma Physics Laboratory (PPPL) This device is presently being updated to enhance its physics by doubling the TF field to 1 Tesla and increasing the plasma current to 2 Mega-amperes. The upgrades include a replacement of the centerstack and addition of a second neutral beam. The upgrade analyses have two missions. The first is to support design of new components, principally the centerstack, the second is to qualify existing NSTX components for higher loads, which will increase by a factor of four. Cost efficiency was a design goal for new equipment qualification, and reanalysis of the existing components. Showing that older components can sustain the increased loads has been a challenging effort in which designs had to be developed that would limit loading on weaker components, and would minimize the extent of modifications needed. Two areas representing this effort have been chosen to describe in more details: analysis of the current distribution in the new TF inner legs, and, second, analysis of the out-of-plane support of the existing TF outer legs.

  1. Upgrade of the CMS tracker

    CERN Document Server

    Tricomi, Alessia

    2014-01-01

    The LHC machine is planning an upgrade program which will smoothly bring the luminosity up to or above $5\\times 10^{34}$ cm$^{-2}$s$^{-1}$ sometimes after 2020, to eventually reach an integrated luminosity of 3000 fb$^{-1}$ at the end of that decade. The foreseen increases of both the instantaneous and the integrated luminosity by the LHC during the next ten years will necessitate a stepwise upgrade of the CMS tracking detector. During the extended end-of-year shutdown 2016-2017 the pixel detector will be exchanged with a new one. The so-called Phase1 Pixel foresees one additional barrel layer and one additional end-cap disk, a new readout chip, reduction of material, and the installation of more efficient cooling and powering systems. In the so-called Phase2, when LHC will reach the High Luminosity (HL-LHC) phase, CMS will need a completely new Tracker detector, in order to fully exploit the high-demanding operating conditions and the delivered luminosity. The new Tracker should have also trigg...

  2. ALICE Upgrades: Plans and Potentials

    CERN Document Server

    Tieulent, Raphael

    2015-01-01

    The ALICE collaboration consolidated and completed the installation of current detectors during LS1 with the aim to accumulate 1 nb$^{-1}$ of Pb-Pb collisions during Run 2 corresponding to about 10 times the Run 1 integrated luminosity. In parallel, the ALICE experiment has a rich detector upgrade programme scheduled during the second LHC long shutdown (LS2, 2018-2019) in order to fully exploit the LHC Runs 3 and 4. The main objectives of this programme are: improving the tracking precision and enabling the read-out of all Pb-Pb interactions at a rate of up to 50 kHz, with the goal to record an integrated luminosity of 10 nb$^{-1}$ after LS2 in minimum-bias trigger mode. This sample would represent an increase by a factor of one hundred with respect to the minimum-bias sample expected during Run 2. The implementation of this upgrade programme, foreseen in LS2, includes: a new low-material Inner Tracking System at central rapidity with a forward rapidity extension to add vertexing capabilities to the current M...

  3. SND data acquisition system upgrade

    International Nuclear Information System (INIS)

    The data acquisition (DAQ) system of the SND detector successfully operated during four data-taking seasons (2010–2013) at the e+e− collider VEPP-2000. Currently the collider is shut down for planned reconstruction, which is expected to increase the VEPP-2000 luminosity and data flow from the SND detector electronics by up to 10 times. Since current DAQ system implementation (electronics and computer part) does not have enough reserve for selection of events in the new environment without compromising quality, there arose the need for the system upgrade. Here we report on the major SND data acquisition system upgrade which includes developing new electronics for digitization and data transfer, complete redesign of the data network, increasing of the DAQ computer farm processing capacity and making the event building process concurrent. These measures will allow us to collect data flow from the most congested detector subsystems in parallel in contrast to the current situation. We would like to discuss also the possibility to implement full software trigger solution in the future

  4. FTU bolometer electronic system upgrade

    International Nuclear Information System (INIS)

    Highlights: ► Design and realization of a new bolometer electronic system. ► Many improvements over the actual commercial system. ► Architecture based on digital electronic hardware with minimal analog front end. ► Auto off-set correction, real time visualization features and small system size. ► Test results for the electronic system. -- Abstract: The FTU (Frascati Tokamak Upgrade) requires a bolometer diagnostic in order to measure the total plasma radiation. The current diagnostic architecture is based on a full analog multichannel AC bolometer system, which uses a carrier frequency amplifier with a synchronous demodulation. Taking into account the technological upgrades in the field of electronics, it was decided to realize an upgrade for the bolometric electronic system by using a hybrid analog/digital implementation. The new system developed at the ENEA Frascati laboratories has many improvements, and mainly a massive system volume reduction, a good measurement linearity and a simplified use. The new hardware system consists of two subsystems: the Bolometer Digital Control and the Bolometer Analog System. The Bolometer Digital Control can control 16 bolometer bridges through the Bolometer Analog System. The Bolometer Digital Control, based on the FPGA architecture, is connected via Ethernet with a PC; therefore, it can receive commands settings from the PC and send the stream of bolometric measurements in real time to the PC. In order to solve the cross-talk between the bridges and the cables, each of the four bridges in the bolometer head receives a different synthesized excitation frequency. Since the system is fully controlled by a PC GUI (Graphic User Interface), it is very user friendly. Moreover, some useful features have been developed, such as: auto off-set correction, bridge amplitude regulation, software gain setting, real time visualization, frequency excitation selection and noise spectrum analyzer embedded function. In this paper, the

  5. FTU bolometer electronic system upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Pollastrone, Fabio, E-mail: fabio.pollastrone@enea.it [Associazione EURATOM-ENEA sulla Fusione, Via Enrico Fermi 45, 00044 Frascati, Rome (Italy); Neri, Carlo; Florean, Marco; Ciccone, Giovanni [Associazione EURATOM-ENEA sulla Fusione, Via Enrico Fermi 45, 00044 Frascati, Rome (Italy)

    2013-10-15

    Highlights: ► Design and realization of a new bolometer electronic system. ► Many improvements over the actual commercial system. ► Architecture based on digital electronic hardware with minimal analog front end. ► Auto off-set correction, real time visualization features and small system size. ► Test results for the electronic system. -- Abstract: The FTU (Frascati Tokamak Upgrade) requires a bolometer diagnostic in order to measure the total plasma radiation. The current diagnostic architecture is based on a full analog multichannel AC bolometer system, which uses a carrier frequency amplifier with a synchronous demodulation. Taking into account the technological upgrades in the field of electronics, it was decided to realize an upgrade for the bolometric electronic system by using a hybrid analog/digital implementation. The new system developed at the ENEA Frascati laboratories has many improvements, and mainly a massive system volume reduction, a good measurement linearity and a simplified use. The new hardware system consists of two subsystems: the Bolometer Digital Control and the Bolometer Analog System. The Bolometer Digital Control can control 16 bolometer bridges through the Bolometer Analog System. The Bolometer Digital Control, based on the FPGA architecture, is connected via Ethernet with a PC; therefore, it can receive commands settings from the PC and send the stream of bolometric measurements in real time to the PC. In order to solve the cross-talk between the bridges and the cables, each of the four bridges in the bolometer head receives a different synthesized excitation frequency. Since the system is fully controlled by a PC GUI (Graphic User Interface), it is very user friendly. Moreover, some useful features have been developed, such as: auto off-set correction, bridge amplitude regulation, software gain setting, real time visualization, frequency excitation selection and noise spectrum analyzer embedded function. In this paper, the

  6. Project W-420 stack monitoring system upgrades

    International Nuclear Information System (INIS)

    This project will execute the design, procurement, construction, startup, and turnover activities for upgrades to the stack monitoring system on selected Tank Waste Remediation System (TWRS) ventilation systems. In this plan, the technical, schedule, and cost baselines are identified, and the roles and responsibilities of project participants are defined for managing the Stack Monitoring System Upgrades, Project W-420

  7. How Can China Achieve Industrial Upgrade?

    Institute of Scientific and Technical Information of China (English)

    汪建成; 毛蕴诗

    2008-01-01

    Traditional OEM enterprises are facing increasing upgrading pressure due to tighten export environment. This paper carries out a comparative case study on two bathroom hardware manufacturers,by analyzing enterprises upgrading process from OEM to ODM and OBM,this article will be a good reference for other Chinese OEM manufacturers who pursue an independent road of innovation.

  8. Alberta oil sands crudes : upgrading and marketing

    Energy Technology Data Exchange (ETDEWEB)

    Ashar, M. [Suncor Energy, Fort McMurray, AB (Canada)

    2008-05-15

    Open pit mining and in situ techniques, such as steam stimulation, are used to recover Alberta's bitumen and heavy oil resources, which have higher viscosities than conventional hydrocarbons. The bitumen is typically upgraded to synthetic crude oil (SCO). In the simplest processing scheme, the bitumen is blended with diluent for ease in pipeline transport and then processed at refineries with upgrading facilities. The bitumen is also upgraded to light SCO at world-scale upgraders in Alberta. The SCO is then processed at refineries in downstream markets. The 2 categories of upgrading, notably primary and secondary upgrading, were described in this article along with technology options for both categories. Slurry hydrocracking is regarded as the most interesting emerging residual fuel upgrading technology. It combines special catalyst mixes with the latest slurry reactor designs as well as innovative catalyst capture and recycle schemes to produce very high conversions and potentially superior upgrading economics. The increase in volume and rate of SCO from Alberta provides refiners in the oil sands marketing sector an unprecedented choice of opportunities to improve profitability. Key trends indicate that production will increase substantially from 2008 to 2030. 5 figs.

  9. ATLAS Phase-II trigger upgrade

    CERN Document Server

    Sankey, Dave; The ATLAS collaboration

    2016-01-01

    This talk for ACES summarises the current status of the ATLAS Phase-II trigger upgrade, describing and comparing the two architectures under consideration, namely the two hardware level system described in the Phase-II Upgrade Scoping Document and the more recent single hardware level system.

  10. Alberta oil sands crudes : upgrading and marketing

    International Nuclear Information System (INIS)

    Open pit mining and in situ techniques, such as steam stimulation, are used to recover Alberta's bitumen and heavy oil resources, which have higher viscosities than conventional hydrocarbons. The bitumen is typically upgraded to synthetic crude oil (SCO). In the simplest processing scheme, the bitumen is blended with diluent for ease in pipeline transport and then processed at refineries with upgrading facilities. The bitumen is also upgraded to light SCO at world-scale upgraders in Alberta. The SCO is then processed at refineries in downstream markets. The 2 categories of upgrading, notably primary and secondary upgrading, were described in this article along with technology options for both categories. Slurry hydrocracking is regarded as the most interesting emerging residual fuel upgrading technology. It combines special catalyst mixes with the latest slurry reactor designs as well as innovative catalyst capture and recycle schemes to produce very high conversions and potentially superior upgrading economics. The increase in volume and rate of SCO from Alberta provides refiners in the oil sands marketing sector an unprecedented choice of opportunities to improve profitability. Key trends indicate that production will increase substantially from 2008 to 2030. 5 figs

  11. Upgrading Subgroup Triple Product Property Triples

    CERN Document Server

    Hedtke, Ivo

    2011-01-01

    In 2003 COHN and UMANS introduced a group-theoretic approach to fast matrix multiplication. This involves finding large subsets of a group $G$ satisfying the Triple Product Property (TPP) as a means to bound the exponent $\\omega$ of matrix multiplication. Recently, Hedtke and Murthy discussed several methods to find TPP triples. Because the search space for subset triples is too large, it is only possible to focus on subgroup triples. We present methods to upgrade a given TPP triple to a bigger TPP triple. If no upgrade is possible we use reduction methods (based on random experiments and heuristics) to create a smaller TPP triple that can be used as input for the upgrade methods. If we apply the upgrade process for subset triples after one step with the upgrade method for subgroup triples we achieve an enlargement of the triple size of 100 % in the best case.

  12. 224-T TRUSAF Building upgrade

    International Nuclear Information System (INIS)

    This study considers the upgrades that would be necessary to extend the life of the Transuranic Waste Storage and Assay Facility (TRUSAF) for an additional 30 years. The study also considers cleanup and conversion of the canyon area of the building for storage of solid waste. The 224-T Building was constructed in the 1940s to support process operations of the T-Plant. The function of the facility has changed over the years, and at present the northern half of the building is used to store solid waste. This portion of the building is referred to as the TRUSAF. TRUSAF is one of only two onsite facilities licensed to receive and store solid TRU wastes. Original intentions were for TRUSAF to be used for TRU solid waste storage until the WRAP 1 Facility became operational

  13. Upgrade Summer Severe Weather Tool

    Science.gov (United States)

    Watson, Leela

    2011-01-01

    The goal of this task was to upgrade to the existing severe weather database by adding observations from the 2010 warm season, update the verification dataset with results from the 2010 warm season, use statistical logistic regression analysis on the database and develop a new forecast tool. The AMU analyzed 7 stability parameters that showed the possibility of providing guidance in forecasting severe weather, calculated verification statistics for the Total Threat Score (TTS), and calculated warm season verification statistics for the 2010 season. The AMU also performed statistical logistic regression analysis on the 22-year severe weather database. The results indicated that the logistic regression equation did not show an increase in skill over the previously developed TTS. The equation showed less accuracy than TTS at predicting severe weather, little ability to distinguish between severe and non-severe weather days, and worse standard categorical accuracy measures and skill scores over TTS.

  14. Fish and shellfish upgrading, traceability.

    Science.gov (United States)

    Guérard, Fabienne; Sellos, Daniel; Le Gal, Yves

    2005-01-01

    Recognition of the limited biological resources and the increasing environmental pollution has emphasised the need for better utilisation of by-products from the fisheries. Currently, the seafood industry is dependent on the processing of the few selected fish and shellfish species that are highly popular with consumers but, from economic and nutritional points of view, it is essential to utilise the entire catch. In this review, we will focus on recent developments and innovations in the field of underutilised marine species and marine by-product upgrading and, more precisely, on two aspects of the bioconversion of wastes from marine organisms, i.e. extraction of enzymes and preparation of protein hydrolysates. We will deal with the question of accurate determination of fish species at the various steps of processing. Methods of genetic identification applicable to fresh fish samples and to derived products will be described. PMID:16566090

  15. ATLAS Nightly Build System Upgrade

    CERN Document Server

    Dimitrov, G; The ATLAS collaboration; Simmons, B; Undrus, A

    2014-01-01

    The ATLAS Nightly Build System is a facility for automatic production of software releases. Being the major component of ATLAS software infrastructure, it supports more than 50 multi-platform branches of nightly releases and provides ample opportunities for testing new packages, for verifying patches to existing software, and for migrating to new platforms and compilers. The Nightly System testing framework runs several hundred integration tests of different granularity and purpose. The nightly releases are distributed and validated, and some are transformed into stable releases used for data processing worldwide. The first LHC long shutdown (2013-2015) activities will elicit increased load on the Nightly System as additional releases and builds are needed to exploit new programming techniques, languages, and profiling tools. This paper describes the plan of the ATLAS Nightly Build System Long Shutdown upgrade. It brings modern database and web technologies into the Nightly System, improves monitoring of nigh...

  16. ATLAS Nightly Build System Upgrade

    CERN Document Server

    Dimitrov, G; The ATLAS collaboration; Simmons, B; Undrus, A

    2013-01-01

    The ATLAS Nightly Build System is a facility for automatic production of software releases. Being the major component of ATLAS software infrastructure, it supports more than 50 multi-platform branches of nightly releases and provides ample opportunities for testing new packages, for verifying patches to existing software, and for migrating to new platforms and compilers. The Nightly System testing framework runs several hundred integration tests of different granularity and purpose. The nightly releases are distributed and validated, and some are transformed into stable releases used for data processing worldwide. The first LHC long shutdown (2013-2015) activities will elicit increased load on the Nightly System as additional releases and builds are needed to exploit new programming techniques, languages, and profiling tools. This paper describes the plan of the ATLAS Nightly Build System Long Shutdown upgrade. It brings modern database and web technologies into the Nightly System, improves monitoring of nigh...

  17. Beam intensity upgrade at Fermilab

    Energy Technology Data Exchange (ETDEWEB)

    Marchionni, A.; /Fermilab

    2006-07-01

    The performance of the Fermilab proton accelerator complex is reviewed. The coming into operation of the NuMI neutrino line and the implementation of slip-stacking to increase the anti-proton production rate has pushed the total beam intensity in the Main Injector up to {approx} 3 x 10{sup 13} protons/pulse. A maximum beam power of 270 kW has been delivered on the NuMI target during the first year of operation. A plan is in place to increase it to 350 kW, in parallel with the operation of the Collider program. As more machines of the Fermilab complex become available with the termination of the Collider operation, a set of upgrades are being planned to reach first 700 kW and then 1.2 MW by reducing the Main Injector cycle time and by implementing proton stacking.

  18. TRIGA Reactor Power Upgrading Analysis

    International Nuclear Information System (INIS)

    Reactor physics safety analysis supporting the power upgrading from 1MW to 2MW of a typical TRIGA Mark II reactor is presented for steady state and pulse operation. The analysis is performed for mixed core configuration consisting of two types of fuel elements: standard 8,5% or 12% stainless-steel clad fuel elements and LEU fuel elements (20% uranium concentration). The following reactor physics codes are applied: WIMS, TRIGAC, EXTERMINATOR, PULSTRI and TRISTAN. Results of the calculations are compared to experiments for steady state operation at 1 MW. The analysis shows that besides technical modifications of the core (installation of an additional control rod) also some strict administrative limitations have to be imposed on operational parameters (excess reactivity, pulse reactivity, core composition) to assure safe operation within design limits. (author)

  19. Energy Efficiency Through Lighting Upgrades

    Energy Technology Data Exchange (ETDEWEB)

    Berst, Kara [Chickasaw Nation, Ada, OK (United States); Howeth, Maria [Chickasaw Nation, Ada, OK (United States)

    2013-02-26

    Lighting upgrades including neon to LED, incandescent to CFL's and T-12 to T-8 and T-5's were completed through this grant. A total of 16 Chickasaw nation facilities decreased their carbon footprint because of these grant funds. Calculations used were based on comparing the energy usage from the previous year's average and the current energy usage. For facilities without a full year's set of energy bills, the month after installation was compared to the same month from the previous year. Overall, the effect the lighting change-outs had for the gaming centers and casinos far exceeded expectations. For the Madill Gaming Center; both an interior and exterior upgrade was performed which resulted in a 31% decrease in energy consumption. This same reduction was seen in every facility that participated in the grant. Just by simply changing out light bulbs to newer energy efficient equivalents, a decrease in energy usage can be achieved and this was validated by the return on investment seen at Chickasaw Nation facilities. Along with the technical project tasks were awareness sessions presented at Chickasaw Head Starts. The positive message of environmental stewardship was passed down to head start students and passed along to Chickasaw employees. Excitement was created in those that learned what they could do to help reduce their energy bills and many followed through and took the idea home. For a fairy low cost, the general public can also use this technique to lower their energy consumption both at home and at work. Although the idea behind the project was somewhat simple, true benefits have been gained through environmental awareness and reductions of energy costs.

  20. Assembly of Aditya upgrade tokamak

    International Nuclear Information System (INIS)

    The existing Aditya tokamak, a medium sized tokamak with limiter configuration is being upgraded to a tokamak with divertor configuration. At present the existing ADITYA tokamak has been dismantled up to bottom plinth on which the whole assembly of toroidal field (TF) coils and vacuum vessel rested. The major components of ADITYA machine includes 20 TF coils and its structural components, 9 Ohmic coils and its clamps, 4 BV coils and its clamps as well as their busbar connections, vacuum vessel and its supports and buckling cylinder, which are all being dismantled. The re-assembly of the ADITYA Upgrade tokamak started with installation and positioning of new buckling cylinder and central solenoid (TR1) coil. After that the inner sections of TF coils are placed following which in-situ winding, installation, positioning and support mounting of two pairs of new inner divertor coils have been carried out. After securing the TF coils with top I-beams the new torus shaped vacuum vessel with circular cross-section in 2 halves have been installed. The assembly of TF structural components such as top and bottom guiding wedges, driving wedges, top and bottom compression ring, inner and outer fish plates and top inverted triangle has been carried out in an appropriate sequence. The assembly of outer sections of TF coils along with the proper placements of top auxiliary TR and vertical field coils with proper alignment and positioning with the optical metrology instrument mainly completes the reassembly. Detailed re-assembly steps and challenges faced during re-assembly will be discussed in this paper. (author)

  1. The upgraders role: Present and future

    International Nuclear Information System (INIS)

    Heavy oil upgrading projects in Canada began in the late 1970s with plans for an upgrader to process Saskatchewan medium and heavy sour crudes. A lower-cost integrated refinery/upgrader option was evaluated, resulting in the first commercial heavy crude oil upgrader in Canada being commissioned at the Consumers' Co-operative Refineries Ltd. (CCRL) refinery. The Co-op upgrader can process 50,000 bbl/d of heavy crude containing up to 4 wt % sulfur, and can tailor blends of synthetic crude oil for refinery customers. Heavy crude supply for upgraders is currently more than adequate. Most heavy crude used in Canada is processed into asphalt, and most Canadian refineries are built to operate on light sweet crude. Synthetic crude processed by carbon rejection presents challenges to a conventional refinery that restrict the volume of synthetic crude that can be run. Synthetic crude processed by hydrogen addition avoids these problems. The Co-op refinery uses the fixed-bed reduced crude desulfurization process which produces upgraded products comparable to those from conventional crude. In the 1970s and 1980s northern USA refineries were built or expanded to handle Canadian heavy crude, exports of which increased from 15,000 bbl/d to 60,000 bbl/d. In Canada, various refineries developed capabilities to handle synthetic crudes produced from heavy oil. Future upgraders include the second generation hydrogen-addition Husky unit that should be operating by summer 1992. A third upgrader is forecast to be built by 2004 if oil prices stay in the US$23-27/bbl range. Expansion and modification of northern US refineries would be the cheapest route to increase upgrading capability of Canadian heavy crude oil

  2. Creating intentionally inviting schools through professional development: an appreciative inquiry

    OpenAIRE

    G.M. Steyn

    2010-01-01

    The professional development (PD) of teachers plays an important role in schools; it is indispensable for continuous school development. When schools are exposed to new approaches to learning and teaching, teachers are granted the opportunities to change their thinking and behaviour. In 2009, two South African schools with specific inviting characteristics were nominated for the inviting school award given by the International Alliance for Invitational Education (IAIE). However, the inviting ...

  3. Abstract Invited Braumann 3rd WSMC 2008

    OpenAIRE

    Braumann, Carlos A.

    2009-01-01

    Invited conference of the joint scientific meeting Third Workshop on Statistics, Mathematics + First Portuguese-Polish Workshop on Biometry (Lisboa, Portugal, July 2008). The conference involved several applications of stochastic differential equations in population growth and animal individual growth, including the issues of extinction, existence of stationary densities and the use of Itô or Stratonovich calculus.

  4. Abstract Invited Braumann 17th IWMS 2008

    OpenAIRE

    Braumann, Carlos A.

    2009-01-01

    Invited conference of the scientific meeting 17th International Workshop on Matrices and Statistics (Tomar, Portugal, July 2008). The conference involved several applications of stochastic differential equations in population growth, harvesting and animal individual growth, including the issues of extinction, existence of stationary densities and the use of Itô or Stratonovich calculus.

  5. STAR Upgrade Plan for the Coming Decade

    International Nuclear Information System (INIS)

    The STAR Collaboration will complete the Heavy Flavor Tracker (HFT) and the Muon Telescope Detector (MTD) upgrades by 2014. STAR has also embarked on an upgrade plan to extend the capabilities for measuring jets, electron/photon and leading particles in the forward rapidity region in the coming decade. Planned detector upgrades include tracking detectors for charged particles, electro-magnetic and hadronic calorimeters and particle identification detector in the forward direction. We will present physics motivations, status of detector R and D and design considerations for the forward measurements focusing on p + p/p + A and polarized p + p collisions

  6. STAR Upgrade Plan for the Coming Decade

    Science.gov (United States)

    Huang, Huan Zhong

    2013-05-01

    The STAR Collaboration will complete the Heavy Flavor Tracker (HFT) and the Muon Telescope Detector (MTD) upgrades by 2014. STAR has also embarked on an upgrade plan to extend the capabilities for measuring jets, electron/photon and leading particles in the forward rapidity region in the coming decade. Planned detector upgrades include tracking detectors for charged particles, electro-magnetic and hadronic calorimeters and particle identification detector in the forward direction. We will present physics motivations, status of detector R&D and design considerations for the forward measurements focusing on p + p/p + A and polarized p + p collisions.

  7. STAR Upgrade Plan for the Coming Decade

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Huan Zhong

    2013-05-02

    The STAR Collaboration will complete the Heavy Flavor Tracker (HFT) and the Muon Telescope Detector (MTD) upgrades by 2014. STAR has also embarked on an upgrade plan to extend the capabilities for measuring jets, electron/photon and leading particles in the forward rapidity region in the coming decade. Planned detector upgrades include tracking detectors for charged particles, electro-magnetic and hadronic calorimeters and particle identification detector in the forward direction. We will present physics motivations, status of detector R and D and design considerations for the forward measurements focusing on p + p/p + A and polarized p + p collisions.

  8. Upgrading messaging system on faculty systems

    OpenAIRE

    Farkaš, Aleš

    2014-01-01

    The graduation thesis provides a solution for the transition a part of mail servers of University of Ljubljana. The transition was carried out from the Microsoft Exchange Server 2003 to Microsoft Exchange Server 2010. Next to upgrade of messaging system, the upgrade of the Active Directory carriers has been needed. For this purpose the upgrade to Windows Server 2008 R2 has been performed. In the first part of the work, the overview of the process of the MS Exchange server and Outlook clie...

  9. Time and space-resolved energy flux measurements in the divertor of the ASDEX tokamak by computerized infrared thermography

    International Nuclear Information System (INIS)

    A new, fully computerized and automatic thermographic system has been developed. Its two central components are an AGA THV 780 infrared camera and a PDP-11/34 computer. A combined analytical-numerical method of solving the 1-dimensional heat diffusion equation for a solid of finite thickness bounded by two parallel planes was developed. In high-density (anti nsub(e) = 8 x 1013 cm-3) neutral-beam-heated (L-mode) divertor discharges in ASDEX, the power deposition on the neutralizer plates is reduced to about 10-15% of the total heating power, owing to the inelastic scattering of the divertor plasma from a neutral gas target. Between 30% and 40% of the power is missing in the global balance. The power flow inside the divertor chambers is restricted to an approximately 1-cm-thick plasma scrape-off layer. This width depends only weakly on the density and heating power. During H-phases free of Edge Localized Mode (ELM) activity the energy flow into the divertor is blocked. During H-phases with ELM activity the energy is expelled into the divertor in very short intense pulses (several MW for about one hundred μs). Sawtooth events are able to transport significant amounts of energy from the plasma core to the peripheral zones and the scrape-off layer, and they are frequently correlated with transitions from the L to the H mode. (orig./AH)

  10. Pellet penetration in ASDEX: a comparison of results computed by means of the ORNL ablation model with measured data

    International Nuclear Information System (INIS)

    The neutral gas plasma shielding (NGPS) ablation model recently proposed by Houlberg et al. has been extensively tested on pellet penetration depths measured in JET. The best fit among calculated and measured penetration depths was obtained by assuming a shielding cloud radius 1 mm larger than the local pellet radius: Rcl = rp + 1 mm, yielding maximum shielding at the end of the pellet liftime (rp = 0). Recently, a model was developed that describes the time evolution of particle clouds in plasmas. With the help of this model, the ionization radius, i.e. the radius of the shielding cloud, can be calculated as a function of the local ablation rate. The results of these calculations show that the shielding cloud radius is proportional to the number of particles locally deposited. The cloud expansion code can be combined with the ORNL ablation model with an Rcl feedback option between the two models. Calculations are performed here for a number of randomly selected pellet-fuelled ASDEX shots. The pellet penetration is calculated for the measured Te(r) and ne(r) profiles by means of the ORNL ablation code with and without Rcl feedback active. (author) 3 figs., 2 tabs

  11. The BABAR Muon System Upgrade

    CERN Document Server

    Menges, W

    2006-01-01

    Resistive Plate Chambers (RPCs) were used for the instrumentation of the iron flux return of the BABAR detector as a muon system. Unfortunately the efficiency of the original RPCs degraded rapidly with time. Limited Streamer Tubes (LSTs) were chosen for an upgrade of the barrel portion of the detector. The phased installation started in summer 2004 with replacing two sextants of the BABAR barrel muon system with LSTs. The modules for the remaining four sextants are under long-term test at SLAC and ready for installation, expected in 2006. The modules become inaccessible once installed in BABAR, so it is critical to select only perfectly working tubes. To accomplish this a strong QC system was established during the prototype phase, and fully implemented throughout pre-production and construction. To spot any damage during transport, the final modules are subjected to comprehensive tests at SLAC immediately after arrival and kept under long-term test till installation into BABAR. Details of these tests and res...

  12. Upgrade of FUMACS code package

    International Nuclear Information System (INIS)

    The FUMACS code package (an acronym of FUel MAnagement Code System) was developed at Rudjer Boskovic Institute in year 1991 with the aim to enable in-core fuel management analysis of the NPP Krsko core for nominal (full power) conditions. The modernization and uprating of the NPP Krsko core from 1876 to 1994 MW (th) performed in year 2000 resulted in the change of operating conditions. The old version of the FUMACS code package would not model properly the NPP Krsko core for the new operating conditions. The upgrade of the FUMACS code package to enable the modeling of the NPP Krsko core for uprated conditions and longer cycles required modifications of master files, libraries and codes. In order to make the code package more user friendly, Windows (95/98/NT) compatible version of the code package, with incorporated graphical user interface has been developed. The new version of the code package has been verified and validated for new operating conditions through modeling and comparison of results with referent design of a number of 12-month and 18-month operating cycles.(author)

  13. Upgraded RECOVER system - CASDAC system

    International Nuclear Information System (INIS)

    The CASDAC (Containment And Surveillance Data Authenticated Communication) system has been developed by JAERI for nuclear safeguards and physical protection of nuclear material. This system was designed and constructed as an upgraded RECOVER system, design concept of which was based on the original RECOVER system and also the TRANSEAVER system. Both of them were developed several years ago as a remote monitoring system for continual verification of security and safeguards status of nuclear material. The system consists of two subsystems, one of them is a Grand Command Center (GCC) subsystem and the other is a facility subsystem. Communication between the two subsystems is controlled through the international telephone line network. Therefore all communication data are encrypted to prevent access by an unauthorized person who may intend to make a falsification, or tapping. The facility subsystem has an appropriate measure that ensure data security and reliable operation under unattended mode of operator. The software of this system is designed so as to be easily used in other different types of computers. This report describes the outline of the CASDAC system and the results of its performance test. This work has been carried out in the framework of Japan Support Programme for Agency Safeguards (JASPAS) as a project, JA-1. (author)

  14. ATLAS nightly build system upgrade

    International Nuclear Information System (INIS)

    The ATLAS Nightly Build System is a facility for automatic production of software releases. Being the major component of ATLAS software infrastructure, it supports more than 50 multi-platform branches of nightly releases and provides ample opportunities for testing new packages, for verifying patches to existing software, and for migrating to new platforms and compilers. The Nightly System testing framework runs several hundred integration tests of different granularity and purpose. The nightly releases are distributed and validated, and some are transformed into stable releases used for data processing worldwide. The first LHC long shutdown (2013-2015) activities will elicit increased load on the Nightly System as additional releases and builds are needed to exploit new programming techniques, languages, and profiling tools. This paper describes the plan of the ATLAS Nightly Build System Long Shutdown upgrade. It brings modern database and web technologies into the Nightly System, improves monitoring of nightly build results, and provides new tools for offline release shifters. We will also outline our long-term plans for distributed nightly releases builds and testing

  15. uc(Pegasus) Facility Upgrades

    Science.gov (United States)

    Quinn, J. C.; Lewicki, B. T.; Burke, S. P.; Eidietis, N. W.; Fonck, R. J.; Ford, B. A.; Garstka, G. D.; Unterberg, E. A.; Winz, G. R.

    2003-10-01

    Extensive new capabilities have been installed on the uc(Pegasus) ST facility. A new laboratory configuration allows separation of all power systems from the experimental hall. Data acquisition, control, and support facilities have been improved. New magnetic field power supplies utilize unique high-power 2700V IGCT switch modules to provide bipolar waveform control for the high-stress solenoid magnet, while 900V IGBTs provide uni/bipolar control of the PF and TF systems. The coil sets are independently controlled by pulse-width-modulated circuits developed by the HIT group. Capacitor charging, dumping, and monitoring are controlled by a PCI-based multichannel data acquisition and control system. These upgrades will provide: 1) increased V-s and loop voltage control for higher plasma current and suppression of MHD modes; 2) increased toroidal field with fast-ramp capability for improved access to the low-q, high βt regime; and 3) flexible equilibrium field control for radial position and modest shape control.

  16. The software upgrade of NICS

    Science.gov (United States)

    Rossetti, Emanuel; Guido, Vincenzo; Oliva, Ernesto

    2008-08-01

    NICS (the Near Infrared Camera Spectrometer) is a cooled near-infrared camera-spectrometer that has been developed in the late 90's at the INAF-Arcetri Astrophysical Observatory for the Ø3.5 m "Telescopio Nazionale Galileo" (TNG) at the La Palma Observatory. The instrument has been operating for regular scientific observations since the beginning of 2001. During the 2001-2007 period it has been used in about 410 nights yielding data which contributed to the production of 60 refereed papers which collected a total of more than 800 citations. At the age of 8 years, NICS is still among the most efficient and versatile infrared instruments existing worldwide. To improve its observational efficiency, we have designed and we are currently developing new control software and GUI interfaces. The former has been devised to optimize the low level tasks (in particular the motors controls), the latter to simplify the communications between the observer and the instrument. We give here a short description of NICS software upgrade.

  17. D0 Silicon Upgrade: Upgrade Piping Loads on Cleanroom Roof

    International Nuclear Information System (INIS)

    The proposed piping layout for the DO upgrade will run along the south wall of DAB. The cryogenic service pipe runs above the upper and lower cleanroom roofs and will need to be supported by the roofs beams. Calculations were done to determine the stresses in the I-beams created by the existing and additional loads due to the upgrade. Refer to drawing no. 3823.115-ME-317283 for drawings of the piping layout. Figure 1 shows the 'plan view' portion of this drawing. The weight of the individual lines were calculated in figure 2 assuming a pipe density of O.28 lbm/in3 for stainless steel (0.12% C) and a fluid density (assuming LN2 at 1 atm) of 0.03 lbm/in3. The weights of the corrugated steel flooring, assembly hall feed cans, support beams, and roof hatch were also included in the analysis. These loads are calculated on pgs. 5-6. A floor load of 50 lbf/ft2 was also added in order to maintain the existing floor load limit in addition to the added piping loads. Measurements of the dimensions of the I-beams determined that the nominal sizes of the beams were W8 x 21 for the lower roof and W14 x 26 for the upper roof. Pipe lengths were determined from the drawing for each of the lines on pgs. 1-2 of the calculations (refer to all piping by line numbers according to figure 2). A total weight was calculated for lines 3-9 along the south wall and lines 1-2 running along the north wall of the lower cleanroom roof. To simplify the calculations these weights were assumed to be evenly distributed on the 5 I-beam supports of the lower cleanroom roof 2.5 feet in from the south wall. The stress analysis was done using FrameMac, a 2-D finite element program for the Macintosh. Beam 3 was not included in the analysis because it is structurally equivalent to beam 1. The program outputted maximum values for shear stress, bending stress, shear force, and moments in each of the beams analyzed. These values were then compared to the allowable stresses as per the specifications and codes

  18. Upgradable Software Product Customization by Code Query

    DEFF Research Database (Denmark)

    Vaucouleur, Sebastien

    The professional press on enterprise systems warns its readers: Costly., A return on investment killer. , Be prepared!. What can create some much af- iction and turmoil in an otherwise very successful industry? Come and meet the dreadful upgrade problem. Enterprise systems are prime examples of a...... subset of software systems that we call software products: software that needs special support for customization. Through customization, external companies can modify part of the original product to better t the needs of a niche market. Upon the release of a new version of the original software product......, external companies must port their customizations to the latest version of the base software product, a process called an upgrade. Companies typically consider upgrades as mandatory, and hence must bear their high cost on a regular basis. The objectives of customizability and upgradability are conicting...

  19. RECOVERY ACT: TAPOCO PROJECT: CHEOAH UPGRADE

    Energy Technology Data Exchange (ETDEWEB)

    Tran, Paul

    2013-02-28

    Under Funding Opportunity Announcement Number: DE-FOA-0000120, Recovery Act: Hydroelectric Facility Modernization, Alcoa Power Generating Inc. (APGI), a fully owned subsidiary of Alcoa Inc., implemented major upgrades at its Cheoah hydroelectric facility near Robbinsville, North Carolina.

  20. CANDU Digital Control Computer upgrade options

    International Nuclear Information System (INIS)

    This paper reviews the evolution of Digital Control Computers (DCC) in CANDU power plants to the present day. Much of this evolution has been to meeting changing control or display requirements as well as the replacement of obsolete, or old and less reliable technology with better equipment that is now available. The current work at AECL and Canadian utilities to investigate DCC upgrade options, alternatives, and strategies are examined. The dependence of a particular upgrade strategy on the overall plant refurbishment plans are also discussed. Presently, the upgrade options range from replacement of individual obsolete system components, to replacement of the entire DCC hardware without changing the software, to complete replacement of the DCCs with a functionally equivalent system using new control computer equipment and software. Key issues, constraints and objectives associated with these DCC upgrade options are highlighted. (author)

  1. Initial performance of upgraded Tevatron cryogenic systems

    International Nuclear Information System (INIS)

    Fermilab began operating a re-designed satellite refrigerator systems in November 1993. Upgrades were installed to operate the Tevatron at a magnet temperature of 3.5 K, approximately 1K lower than the original design. Refrigerator upgrades included new valve boxes, larger reciprocating expanders, the installation of cold vapor compressors, new sub-atmospheric instrumentation and an entirely new distributed controls system. Cryogenic system reliability data for Colliding Physics Run 1B is presented emphasizing a failure analysis for each aspect of the upgrade. Comparison to data for Colliding Physics Run 1A (previous to upgrade) is presented to show the impact of a major system overhaul. New operational problems and their solutions are presented in detail

  2. TMX Upgrade magnet-set geometry design

    International Nuclear Information System (INIS)

    A magnet set, consisting of 24 coils, has been designed for the TMX Upgrade. Like the coil set designed for the TMX experiment, the coils for TMX Upgrade consist of a central-cell set with a minimum-B plug set on each end. Between the central cell and each end plug, there is a flux bundle recircularizing transition set. Physics considerations require that the TMX Upgrade magnet set be almost twice as long as the TMX magnet set (14 m between the outer mirrors). The central circular coils are the only coils used from TMX. The TMX transition set of two C-coils and an octupole is replaced by a C-coil and an Ioffe coil. The TMX plug composed of a baseball coil and two C-coils is replaced by an Ioffe coil, two C-coils and two circular coils. A comparison between the TMX and TMX Upgrade magnet sets is shown

  3. Pakistan research reactor-1 and its upgradation

    International Nuclear Information System (INIS)

    In this article the author describes the procedure of renovation and upgradation of a swimming pool type Pakistan Research Reactor-1 (PARR-1) installed at PINSTECH. The reactor originally designed for a thermal power of 5 MW using highly enriched uranium as has been upgraded 10 MW with low enriched uranium as fuel. All the required safety precaution has been also modified with the new requirements. The cooling system of PARR-1 was modified to meet the requirements of upgraded power of 10 MW. In order to ensure safety for upgraded PARR-1 and to bring the reactor the current safety standards, some additional safety systems have been provided. An emergency core cooling system ECCS has been installed to remove core decay heat in case of loss of coolant accident (LOCA). (A.B.)

  4. Upgrading of solid biofuels and feedstock quality

    Energy Technology Data Exchange (ETDEWEB)

    Burvall, Jan [Swedish Univ. of Agricultural Sciences, Umeaa (Sweden). Dept. of Agricultural Research for Northern Sweden

    1998-06-01

    This paper treats upgrading of biomass to pellets, briquettes and powder and the quality needed of the initial feedstock. The main raw materials are wood and reed canary grass (Phalaris arundinacea L.) 5 refs, 6 figs, 2 tabs

  5. CDF Central Preshower and Crack Detector Upgrade

    OpenAIRE

    Artikov, A.

    2007-01-01

    The CDF Central Preshower and Crack Detector Upgrade consist of scintillator tiles with embedded wavelength-shifting fibers, clear-fiber optical cables, and multi-anode photomultiplier readout. A description of the detector design, test results from R&D studies, and construction phase are reported. The upgrade was installed late in 2004, and a large amount of proton-antiproton collider data has been collected since then. Detector studies using those data are also discussed.

  6. Steam turbine upgrade at the Dukovany NPP

    International Nuclear Information System (INIS)

    Czech and Slovak VVER-440 reactor units are equipped with Skoda 220MW condensing steam turbines, which .are three-casing reheat turbines operating with saturated steam. In consecutive steps, their upgrade focused on the condensers, the flow paths of low-pressure and high-pressure turbine sections and on the high-pressure feed water heaters. This paper covers selected technical aspects of the upgrade of the condensers and turbine flow paths. (orig.)

  7. Innovation and upgrading in global production networks

    OpenAIRE

    Dev Nathan; Sandip Sarkar

    2013-01-01

    Abstract This paper deals with the role of innovation in upgrading within global production networks (GPNs). Because of the distribution of production segments across firms and countries, there is also a distribution of production knowledge. The paper looks at some ways of upgrading by developing economy firms – the roles of distributed knowledge, reverse innovation and new types of innovation, based on frugal engineering in emerging economies. Process changes could also be innovation, though...

  8. BNL ACCELERATOR TEST FACILITY CONTROL SYSTEM UPGRADE.

    Energy Technology Data Exchange (ETDEWEB)

    MALONE,R.; BEN-ZVI,I.; WANG,X.; YAKIMENKO,V.

    2001-06-18

    Brookhaven National Laboratory's Accelerator Test Facility (ATF) has embarked on a complete upgrade of its decade old computer system. The planned improvements affect every major component: processors (Intel Pentium replaces VAXes), operating system (Linux/Real-Time Linux supplants OpenVMS), and data acquisition equipment (fast Ethernet equipment replaces CAMAC serial highway.) This paper summarizes the strategies and progress of the upgrade along with plans for future expansion.

  9. Combined Electrolysis and Catalytic Exchange (CECE) upgraders - an alternative to Water Distillation (DW) heavy water upgraders

    International Nuclear Information System (INIS)

    All operating CANDU stations are equipped with Water Distillation (DW) systems for heavy water upgrading. An alternative process, Combined Electrolysis and Catalytic Exchange (CECE), is being considered for use in future CANDU stations. The CECE process has several operating advantages over DW systems, including lower emissions and heavy water losses. Changes in nuclear standards may change seismic requirements and classification of upgrader systems. These changes will likely increase the cost of heavy water upgraders, but the cost increase will be smaller for a CECE upgrader. Research at Chalk River Labs has identified materials for use in the CECE process that will not chemically or mechanically degrade when exposed to highly tritiated water. (author)

  10. Pulsed power supply for Nova Upgrade

    International Nuclear Information System (INIS)

    This report describes work carried out at the Center for Electromechanics at The University of Texas at Austin (CEM-UT). A baseline design of the Nova Upgrade has been completed by Lawrence Livermore National Laboratory. The Nova Upgrade is an 18 beamline Nd: glass laser design utilizing fully relayed 4x4 30 cm aperture segmented optical components. The laser thus consists of 288 independent beamlets nominally producing 1.5 to 2.0 MJ of 0.35 μm light in a 3 to 5 ns pulse. The laser design is extremely flexible and will allow a wide range of pulses to irradiate ICF targets. This facility will demonstrate ignition/gain and the scientific feasibility of ICF for energy and defense applications. The pulsed power requirements for the Nova Upgrade are given. CEM-UT was contracted to study and develop a design for a homopolar generator/inductor (HPG/inductor) opening switch system which would satisfy the pulsed power supply requirements of the Nova Upgrade. The Nd:glass laser amplifiers used in the Nova Upgrade will be powered by light from xenon flashlamps. The pulsed power supply for the Nova Upgrade powers the xenon flashlamps. This design and study was for a power supply to drive flashlamps

  11. IPNS upgrade: A feasibility study

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-04-01

    Many of Argonne National Laboratory`s (ANL`s) scientific staff members were very active in R&D work related to accelerator-based spoliation sources in the 1970s and early 1980s. In 1984, the Seitz/Eastman Panel of the National Academy of Sciences reviewed U.S. materials science research facilities. One of the recommendations of this panel was that the United States build a reactor-based steady-state source, the Advanced Neutron Source (ANS), at Oak Ridge National Laboratory. Subsequently, R&D activities related to the design of an accelerator-based source assumed a lower priority. The resumption of pulsed-source studies in this country started simultaneously with design activities in Europe aimed at the European Spallation Source (ESS). The European Community funded a workshop in September 1991 to define the parameters of the ESS. Participants in this workshop included both accelerator builders and neutron source users. A consortium of European countries has proposed to build a 5-MW pulsed source, and a feasibility study is currently under way. Soon after the birth of the ESS, a small group at ANL set about bringing themselves up to date on pulsed-source information since 1984 and studied the feasibility of upgrading ANL`s Intense Pulsed Neutron Source (IPNS) to 1 MW by means of a rapidly cycling synchrotron that could be housed, along with its support facilities, in existing buildings. In early 1993, the Kohn panel recommended that (1) design and construction of the ANS should be completed according to the proposed project schedule and (2) development of competitive proposals for cost-effective design and construction of a 1-MW pulsed spallation source should be authorized immediately.

  12. PSL Icing Facility Upgrade Overview

    Science.gov (United States)

    Griffin, Thomas A.; Dicki, Dennis J.; Lizanich, Paul J.

    2014-01-01

    The NASA Glenn Research Center Propulsion Systems Lab (PSL) was recently upgraded to perform engine inlet ice crystal testing in an altitude environment. The system installed 10 spray bars in the inlet plenum for ice crystal generation using 222 spray nozzles. As an altitude test chamber, the PSL is capable of simulating icing events at altitude in a groundtest facility. The system was designed to operate at altitudes from 4,000 to 40,000 ft at Mach numbers up to 0.8M and inlet total temperatures from -60 to +15 degF. This paper and presentation will be part of a series of presentations on PSL Icing and will cover the development of the icing capability through design, developmental testing, installation, initial calibration, and validation engine testing. Information will be presented on the design criteria and process, spray bar developmental testing at Cox and Co., system capabilities, and initial calibration and engine validation test. The PSL icing system was designed to provide NASA and the icing community with a facility that could be used for research studies of engine icing by duplicating in-flight events in a controlled ground-test facility. With the system and the altitude chamber we can produce flight conditions and cloud environments to simulate those encountered in flight. The icing system can be controlled to set various cloud uniformities, droplet median volumetric diameter (MVD), and icing water content (IWC) through a wide variety of conditions. The PSL chamber can set altitudes, Mach numbers, and temperatures of interest to the icing community and also has the instrumentation capability of measuring engine performance during icing testing. PSL last year completed the calibration and initial engine validation of the facility utilizing a Honeywell ALF502-R5 engine and has duplicated in-flight roll back conditions experienced during flight testing. This paper will summarize the modifications and buildup of the facility to accomplish these tests.

  13. IPNS upgrade: A feasibility study

    International Nuclear Information System (INIS)

    Many of Argonne National Laboratory's (ANL's) scientific staff members were very active in R ampersand D work related to accelerator-based spoliation sources in the 1970s and early 1980s. In 1984, the Seitz/Eastman Panel of the National Academy of Sciences reviewed U.S. materials science research facilities. One of the recommendations of this panel was that the United States build a reactor-based steady-state source, the Advanced Neutron Source (ANS), at Oak Ridge National Laboratory. Subsequently, R ampersand D activities related to the design of an accelerator-based source assumed a lower priority. The resumption of pulsed-source studies in this country started simultaneously with design activities in Europe aimed at the European Spallation Source (ESS). The European Community funded a workshop in September 1991 to define the parameters of the ESS. Participants in this workshop included both accelerator builders and neutron source users. A consortium of European countries has proposed to build a 5-MW pulsed source, and a feasibility study is currently under way. Soon after the birth of the ESS, a small group at ANL set about bringing themselves up to date on pulsed-source information since 1984 and studied the feasibility of upgrading ANL's Intense Pulsed Neutron Source (IPNS) to 1 MW by means of a rapidly cycling synchrotron that could be housed, along with its support facilities, in existing buildings. In early 1993, the Kohn panel recommended that (1) design and construction of the ANS should be completed according to the proposed project schedule and (2) development of competitive proposals for cost-effective design and construction of a 1-MW pulsed spallation source should be authorized immediately

  14. Design upgrading on Ignitor Machine

    International Nuclear Information System (INIS)

    Ignitor is a high field compact machine conceived to achieve ignition in D-T plasma. The upgraded design of the Plasma Chamber (PC) and of the First Wall (FW) system consider the updated scenarios for IGNITOR vertical plasma disruption (VDE). The electromagnetic (EM) loads arising from halo currents and net horizontal force with the proper toroidal distribution have been envisaged. The dynamic elastic-plastic structural analysis of the PC has brought to a tayloring of the wall thickness such to reduce the displacements within the clearance with toroidal coil. A detailed 3D finite elements model has been developed in order to evaluate the electromagnetic loads on FW. The thermal loads arisen from plasma heat loads (peak value 1.8 MW/m2) have been also considered. In any case the maximum calculated stresses are within the allowable limits. The relevant 3D virtual mockup software simulates the inside of the PC including the entire boom with end-effector. This allowed for the analysis of the boom kinematics to cover all positions with the various end-effectors to assess the Remote Handling task operations. The structural analysis of the IGNITOR machine Load Assembly has been performed taking into account the friction coefficients between the significant components. The non linear analysis takes into account for both the in-plane and the out-of-plane loads. The vertical plasma disruption conditions (VDE) result in bigger out-of-plane loads than the normal operating conditions. Keys of proper dimensions between the 30o extension C-Clamps modules was adopted to assure structural stability. As far as the interlaminar shear stresses on toroidal field coils are concerned, the related safety factors are decreased respect to the normal operating conditions, but remaining around 2. (author)

  15. Invited presentations. College on soil physics 2003

    International Nuclear Information System (INIS)

    The present book is a partial compilation of contributions from selected former participants of the College on Soil Physics invited to make presentations related to their achievements as a result of attending the College. It also serves as a testimony of the existing links between soil physicists throughout the world strengthened by the support and programs of the International Centre for Theoretical Physics originally envisioned by Abdus Salam to foster the growth of advanced studies and physics research in developing countries

  16. Breaking the megaproject paradigm: Regional upgrading

    International Nuclear Information System (INIS)

    A discussion is presented of the changing circumstances that impact on the future relationship between upgrading of Athabasca bitumen and the bitumen production operations which supply the feedstock. In the early years of oil sands development in Alberta, initial proposals for bitumen upgrading were based on large-scale operations integrated with oil sand production. After over 25 years of commercial operation, further development of Alberta's oil sands is at a crossroads, and positive steps need to be taken today in order to prepare for future growth. Advances in surface extraction technology have reduced capital costs and halved the process energy requirements, while gains in upgrading technology have been more incremental. Environmental requirements have become more stringent, leading to increasing costs for establishing new mine sites, for limiting emissions from new upgrading capacity, and for producing the quality of fuel products for future markets. The Syncrude and Suncor operations are approaching the limits of their original mines. In the Athabasca deposit, in-situ production is not yet sufficiently advanced to be employed for immediate large-scale replacement of surface mine based capacity. Upgrading of bitumen, which requires some kind of thermal cracking or hydroconversion process, remains capital-intensive. It is clear that obstacles to new integrated operations or independent upgrading operations are at least as formidable as in the past. Managed growth of existing upgraders or refineries is seen as the best near-term prospect for the oil sands to make additional increases of supply to Canada's petroleum needs. 6 figs., 2 tabs

  17. Safety upgrades to the NRU research reactor

    International Nuclear Information System (INIS)

    The NRU (National Research Universal) Reactor is a 135 MW thermal research facility located at Chalk River Laboratories, and is owned and operated by Atomic Energy of Canada Limited. One of the largest and most versatile research reactors in the world, it serves as the R and D workhorse for Canada's CANDU business while at the same time filling the role as one of the world's major producers of medical radioisotopes. AECL plans to extend operation of the NRU reactor to approximately the year 2005 when a new replacement, the Irradiation Research Facility (IRF) will be available. To achieve this, AECL has undertaken a program of safety reassessment and upgrades to enhance the level of safety consistent with modem requirements. An engineering assessment/inspection of critical systems, equipment and components was completed and seven major safety upgrades are being designed and installed. These upgrades will significantly reduce the reactor's vulnerability to common mode failures and external hazards, with particular emphasis on seismic protection. The scheduled completion date for the project is 1999 December at a cost approximately twice the annual operating cost. All work on the NRU upgrade project is planned and integrated into the regular operating cycles of the reactor; no major outages are anticipated. This paper describes the safety upgrades and discusses the technical and managerial challenges involved in extending the operating life of the NRU reactor. (author)

  18. Climate balance of biogas upgrading systems

    International Nuclear Information System (INIS)

    One of the numerous applications of renewable energy is represented by the use of upgraded biogas where needed by feeding into the gas grid. The aim of the present study was to identify an upgrading scenario featuring minimum overall GHG emissions. The study was based on a life-cycle approach taking into account also GHG emissions resulting from plant cultivation to the process of energy conversion. For anaerobic digestion two substrates have been taken into account: (1) agricultural resources and (2) municipal organic waste. The study provides results for four different upgrading technologies including the BABIU (Bottom Ash for Biogas Upgrading) method. As the transport of bottom ash is a critical factor implicated in the BABIU-method, different transport distances and means of conveyance (lorry, train) have been considered. Furthermore, aspects including biogas compression and energy conversion in a combined heat and power plant were assessed. GHG emissions from a conventional energy supply system (natural gas) have been estimated as reference scenario. The main findings obtained underlined how the overall reduction of GHG emissions may be rather limited, for example for an agricultural context in which PSA-scenarios emit only 10% less greenhouse gases than the reference scenario. The BABIU-method constitutes an efficient upgrading method capable of attaining a high reduction of GHG emission by sequestration of CO2.

  19. Upgrade of the ALICE Inner Tracking System

    CERN Document Server

    Belikov, Iouri

    2016-01-01

    A Large Ion Collider Experiment (ALICE) is built to study the properties of the strongly interacting matter created in heavy-ion collisions at the LHC. With the upgrade of its Inner Tracking System (ITS), the ALICE experiment is going to increase the rate of data taking by almost two orders of magnitude. At the same time, the precision of secondary vertex reconstruction will become by at least a factor 3 better than it currently is. In this talk, we briefly show some selected physics results motivating the upgrade of the ITS, describe the design goals and the layout of the new detector, and highlight a few important measurements that will be realized after the completion of this upgrade.

  20. Upgrade of the Tevatron cryogenic system

    International Nuclear Information System (INIS)

    Fermilabs superconducting Tevatron accelerator has reached its tenth year of operation. This year, three significant upgrades to the cryogenic system will become operational; a second central helium liquefier, a Tevatron satellite refrigerator lower temperature upgrade, and a satellite refrigerator controls system upgrade. The decision to build a second central helium liquefier (CHL) was originally based on redundancy; protecting accelerator operation from a major CHL failure such as a heat exchanger. Higher capacity turbines were used in the second coldbox, which will result in an estimated 5400 liters per hour production rate. Preliminary commissioning of the coldbox took place in 1992. Full capacity testing will take place in 1993. To aid in the discovery of the top quark, it is desirable to increase the particle energy in the Tevatron accelerator. The machine is limited to an energy of 900 GeV due to magnet conductor short sample current at the existing operating temperature. An upgrade is underway to lower the temperature of the accelerator ∼1K. The short term goal is 1000 GeV operation with a 1100 GeV long term goal. Cold vapor compressors will be used in each of the 24 satellite refrigerators to achieve the temperature reduction. An upgrade of the existing satellite refrigerator controls system is necessary to incorporate the added control devices, instrumentation, and controls algorithms required by the low temperature upgrade. The existing Z80 Multibus I based system will be replaced with a 386 Multibus II system. New features will be incorporated, including processor to processor communications, fast event driven circular buffer, hierarchical alarm system, higher level language support, and more elaborate controlling algorithms