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Sample records for asdex upgrade tokamak

  1. 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...

  2. 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.

  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

    NARCIS (Netherlands)

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

    2013-01-01

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

  5. 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.

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

    Science.gov (United States)

    Äkäslompolo, S.; Bonheure, G.; Tardini, G.; Kurki-Suonio, T.; The ASDEX Upgrade Team

    2015-10-01

    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 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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-07-01

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

  8. 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...

  9. 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.

  10. Neue Anwendungsgebiete der Elektronzyklotronresonanzheizung an ASDEX Upgrade

    OpenAIRE

    Höhnle, Hendrik

    2012-01-01

    In dieser Arbeit wurden Heizszenarien der Elektronzyklotronresonanzheizung (ECRH) für neue Parametergebiete am Tokamak ASDEX Upgrade im Hinblick auf ITER entwickelt. Die ECRH wird seit dem Umbau des Materials der ersten Wand von Kohlenstoff zu Wolfram auch für die Kontrolle der Wolframkonzentration im Plasmazentrum gebraucht. In ITER-relevanten Entladungen an ASDEX Upgrade wird der Einsatz der ECRH in der üblich verwendeten außerordentlichen Mode an der zweiten Harmonischen (X2-Mode) jedoch b...

  11. 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.

  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. 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.

  14. 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

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

    Energy Technology Data Exchange (ETDEWEB)

    Casali, Livia

    2015-11-24

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

  16. A fast acquisition rate system for charge exchange measurements at the plasma edge at the ASDEX Upgrade tokamak

    CERN Document Server

    Cavedon, Marco; Viezzer, Eleonora; Dux, Ralph; Geiger, Benedikt; McDermott, Rachael Marie; Meyer, Hendrik; Stroth, Ulrich

    2016-01-01

    In this work, a new type of high through-put Czerny-Turner spectrometer has been developed which allows to acquire multiple channels simultaneously with a repetition time on the order of \\SI{10}{\\us} at different wavelengths. The spectrometer has been coupled to the edge charge exchange recombination system at ASDEX Upgrade which has been recently refurbished with new lines of sight. Construction features, calibration methods, and initial measurements obtained with the new setup will be presented.

  17. 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...

  18. 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...

  19. 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

  20. ICRF wave field measurements in the presence of scrape off layer turbulence on the ASDEX Upgrade tokamak (invited)

    Science.gov (United States)

    Ochoukov, R.; Bobkov, V.; Faugel, H.; Fünfgelder, H.; Jacquot, J.; Noterdaeme, J.-M.; Suárez López, G.

    2016-11-01

    A new array of B-dot probes was installed on ASDEX Upgrade. The purpose of the new diagnostic is to study Ion Cyclotron Range-off Frequencies (ICRF) wave field distributions in the evanescent scrape-off layer (SOL) plasma region on the low field side of ASDEX Upgrade. The vacuum measurements (no gas, BT = 0 T) reveal ICRF wave field measurements consistent with the profiles expected from the newly installed 3-strap ICRF antennas outside the antenna box: the shape of the toroidal distribution of both the amplitude and the phase is the same for the case of only the central straps being active, as for the case of only the side straps being active. These profiles become strongly modified during plasma operations. The modifications can be separated into two types: "Inter-edge localized mode (ELM)" and "During-ELM" periods. The phase distribution of the ICRF wave fields remains well-defined during the Inter-ELM period; however, it becomes more spread out over the entire 360° range during ELMs. The observed modulations cannot be explained by the observed changes in the ICRF power, as monitored in the transmission line. However, they are consistent with ICRF coupling changes introduced by plasma filaments: the plasma density perturbations due to the filaments are high enough to change the nature of the fast ICRF wave field from evanescent to propagating. The coverage of the present diagnostic is being expanded to include both the low field side and the high field side probes. Additionally, a manipulator probe head is being developed to measure ICRF wave field radial profiles across the SOL region.

  1. Growth of axisymmetric instabilities in ASDEX upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Sehmer, Till; Lackner, Karl; Strumberger, Erika; Fable, Emiliano; Kardaun, Otto [Max-Planck-Institut fuer Plasma-Physik, EURATOM Association Boltzmannstrasse 2, 85748 Garching (Germany); McCarthy, Patrick [University College Cork (Ireland)

    2014-07-01

    Modern poloidal divertor tokamaks, such as ASDEX upgrade (AUG), produce elongated plasmas, which are unstable against vertical displacement. The growth rate of this 2D instability in the presence of stabilizing passive conductors (PSL) with finite resistivity was calculated for 5416 AUG typical equilibria. For this, a general ideal MHD code package (NEMEC, CAS3DN, STARWALL) was used, which is able to take into account also the 3D structure of the PSL. The comparison of the resulting growth rates with the previously used rigid displacement model (movement only in z-direction, no skin effect for PSL considered, no induced surface currents) shows that the latter simplified model gives a consistently lower limit for typical AUG parameters (elongation, triangularity, current profile and axis position in radial direction). A statistical analysis of the results of the rigid displacement model shows the expected dependencies except for the triangularity, which has a stabilizing effect in this model. Based on results of our present, more general model, we conclude that a rigid displacement model gives an over-optimistic result regarding the effect of triangularity, in line with the experimental observation on AUG of an increasing discrepancy between previously predicted and observed growth rates for strongly triangular plasmas.

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

    DEFF Research Database (Denmark)

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

    2008-01-01

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

  3. 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...

  4. A large divertor manipulator for ASDEX Upgrade

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-10-15

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

  5. 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

  6. The enhanced ASDEX Upgrade pellet centrifuge launcher

    Science.gov (United States)

    Plöckl, B.; Lang, P. T.

    2013-10-01

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

  7. Characterisation of the core poloidal flow at ASDEX upgrade

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-07-01

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

  8. Piezoelectric valve for massive gas injection in ASDEX upgrade

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-07-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-07-01

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

  10. 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 PLH occurs indicates that ITER could take advantage of it to initiate H-mode at lower density than that of the final Q = 10 operational point. Core density fluctuation measurements resolved in radius and wave number show that an increase of R/LTe introduced by off-axis electron cyclotron resonance heating (ECRH) mainly increases the large scale fluctuations. The radial variation of the fluctuation level is in agreement with simulations using the GENE code. Fast particles are shown to undergo classical slowing down in the absence of large scale magnetohydrodynamic (MHD) events and for low heating power, but show signs of anomalous radial redistribution at large heating power, consistent with a broadened off-axis neutral beam current drive current profile under these conditions. Neoclassical tearing mode (NTM) suppression experiments using electron cyclotron current drive (ECCD) with feedback controlled deposition have allowed to test several control strategies for ITER, including automated control of (3,2) and (2,1) NTMs during a single 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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-10-15

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

  12. A fast feedback controlled magnetic drive for the ASDEX Upgrade fast-ion loss detectors

    Science.gov (United States)

    Ayllon-Guerola, J.; Gonzalez-Martin, J.; Garcia-Munoz, M.; Rivero-Rodriguez, J.; Herrmann, A.; Vorbrugg, S.; Leitenstern, P.; Zoletnik, S.; Galdon, J.; Garcia Lopez, J.; Rodriguez-Ramos, M.; Sanchis-Sanchez, L.; Dominguez, A. D.; Kocan, M.; Gunn, J. P.; Garcia-Vallejo, D.; Dominguez, J.

    2016-11-01

    A magnetically driven fast-ion loss detector system for the ASDEX Upgrade tokamak has been designed and will be presented here. The device is feedback controlled to adapt the detector head position to the heat load and physics requirements. Dynamic simulations have been performed taking into account effects such as friction, coil self-induction, and eddy currents. A real time positioning control algorithm to maximize the detector operational window has been developed. This algorithm considers dynamical behavior and mechanical resistance as well as measured and predicted thermal loads. The mechanical design and real time predictive algorithm presented here may be used for other reciprocating systems.

  13. Fringe jump analysis and implementation of polarimetry on the ASDEX Upgrade DCN interferometer.

    Science.gov (United States)

    Mlynek, A; Casali, L; Ford, O; Eixenberger, H

    2014-11-01

    The ASDEX Upgrade tokamak is equipped with a 5-channel DCN interferometer with a probing wavelength of 195 μm. Up to now, phase measurement and density calculation have been accomplished by hard-wired phase counting electronics. Meanwhile, a fast digitizer has been installed which acquires the raw signals. That way, the various causes of counting errors by integer multiples of 2π, so-called fringe jumps, can be analyzed, and phase reconstruction schemes based on digital signal processing can be developed. In addition, a prototype polarimeter setup has been installed on one channel and allows for measurement of the Faraday rotation experienced by the probing beam.

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

    Energy Technology Data Exchange (ETDEWEB)

    Granetz, R.; Gruber, O.; Zohm, H. [and others

    1994-09-01

    The emphasis of this year`s ASDEX/DOE workshop was on disruptions in diverted tokamaks. The meeting was held here at MIT on 14--15 March. It is particularly appropriate that MIT hosted the workshop this year, since Alcator C-Mod had just recently completed its very first run campaign, and disruptions are one of the key areas of research in our program. There were a total of 14 speakers, with participants from IPP (Garching), CRPP (Lausanne), Culham, General Atomics, PPPL, Sandia, ORNL, the ITER JCT, and MIT. The subjects addressed included statistical analysis of disruption probabilities in ASDEX, modelling of the vertical axisymmetric plasma motion in DIII-D, impact of disruptions on the design of the ITER divertors, modelling of runaway electrons, and TSC calculations of disruption-induced currents and forces in TPX, etc. One item of particular interest to us was the experimental correlation of halo current magnitude with plasma current on ASDEX-Upgrade. The data indicates at least a linear, and possibly even a quadractic dependence. This has important implications for Alcator C-Mod, since it would predict halo currents of order 1 MA or more at full performance. At the conclusion of the talks, an informal discussion of disruption databases was held, primarily for the purpose of helping us develop a useful one for C-Mod.

  15. 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...

  16. 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.

  17. On the effect of neoclassical flows on intrinsic momentum in ASDEX Upgrade Ohmic L-mode plasmas

    Science.gov (United States)

    Hornsby, W. A.; Angioni, C.; Fable, E.; Manas, P.; McDermott, R.; Peeters, A. G.; Barnes, M.; Parra, F.; The ASDEX Upgrade Team

    2017-04-01

    A gyro-kinetic analysis of intrinsic rotation is presented for the ASDEX Upgrade tokamak. The gyro-kinetic turbulence code, GKW and the neoclassical transport code, NEO are coupled so that the neoclassical equilibrium distribution function is included in the background distribution function in the gyro-kinetic turbulence simulation. This implementation is benchmarked against a similar implementation in the gyro-kinetic code, GS2 (Dorland et al 2000 Phys. Rev. Lett. 85 5579) and against analytical predictions. A quasi-linear and non-linear gyro-kinetic turbulence analysis is performed on Ohmic L-mode ASDEX Upgrade plasmas showing that the symmetry breaking effects due to neoclassical background flows can produce significant toroidal momentum transport. While its magnitude is of the order of other symmetry breaking mechanisms, such as the Coriolis pinch, up–down asymmetry in the magnetic flux surfaces and E× B flow shear, the flow gradients it can sustain are appreciably smaller than the maximum gradients measured at the mid-radius of the ASDEX Upgrade tokamak core, which can be up to an order of magnitude larger. It is found that the gradient of the diamagnetic flow, and therefore the second derivatives of the density and temperature gradients are critical to the production of residual toroidal momentum flux. A quasi-linear estimate indicated that the second derivatives required to match the experimental flow gradient are up to an order of magnitude higher than the measured second derivatives. This analysis suggests that turbulent transport driven by neoclassical flows is not sufficient to explain the maximum flow gradients observed in ASDEX Upgrade.

  18. Imaging motional Stark effect measurements at ASDEX Upgrade

    Science.gov (United States)

    Ford, O. P.; Burckhart, A.; McDermott, R.; Pütterich, T.; Wolf, R. C.

    2016-11-01

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

  19. 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.

  20. Development of the Q  =  10 scenario for ITER on ASDEX Upgrade (AUG)

    Science.gov (United States)

    Schweinzer, J.; Beurskens, M.; Frassinetti, L.; Joffrin, E.; Bobkov, V.; Dux, R.; Fischer, R.; Fuchs, C.; Kallenbach, A.; Hopf, C.; Lang, P. T.; Mlynek, A.; Pütterich, T.; Ryter, F.; Stober, J.; Tardini, G.; Wolfrum, E.; Zohm, H.; the EUROfusion MST1 Team; the ASDEX Upgrade Team

    2016-10-01

    The development of the baseline H-mode scenario foreseen for ITER on the ASDEX Upgrade tokamak, i.e. discharges at q 95  =  3, relatively low β N ~ 1.8, high normalized density n/n GW ~ 0.85 and high triangularity δ  =  0.4, focused on the integration of elements foreseen for ITER and available on ASDEX Upgrade, such as ELM mitigation techniques and impurity seeding in combination with a metallic wall. Values for density and energy confinement simultaneously came close to the requirements of the ITER baseline scenario as long as β N stayed above 2. At lower heating power and thus lower β N normalized energy confinement H 98y2 ~ 0.85 is obtained. It has been found that stationary discharges are not easily achieved under these conditions due to the low natural ELM frequency occurring at the low q 95/high δ operational point. Up until now the ELM parameters were uncontrollable with the tools developed in other scenarios. Therefore studies on an alternative operational point at higher β N and q 95 have been conducted. In order to prepare for the ITER first non-activation operational phase, Helium operation has been investigated as well.

  1. 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.

  2. Electromagnetic effects on turbulent transport in high-performance ASDEX Upgrade discharges

    Energy Technology Data Exchange (ETDEWEB)

    Doerk, H.; Dunne, M.; Ryter, F.; Schneider, P. A.; Wolfrum, E. [Max-Planck-Institut für Plasmaphysik, Boltzmannstraße 2, D-85748 Garching (Germany); Jenko, F. [Max-Planck-Institut für Plasmaphysik, Boltzmannstraße 2, D-85748 Garching (Germany); Department of Physics and Astronomy, University of California, Los Angeles, California 90095 (United States)

    2015-04-15

    Modern tokamak H-mode discharges routinely operate at high plasma beta. Dedicated experiments performed on multiple machines measure contradicting dependence of the plasma confinement on this important parameter. In view of designing high-performance scenarios for next-generation devices like ITER, a fundamental understanding of the involved physics is crucial. Theoretical results—most of which have been obtained for simplified setups—indicate that increased beta does not only modify the characteristics of microturbulence but also potentially introduces fundamentally new physics. Empowered by highly accurate measurements at ASDEX Upgrade, the GENE turbulence code is used to perform a comprehensive gyrokinetic study of dedicated H-Mode plasmas. We find the stabilization of ion-temperature-gradient driven turbulence to be the most pronounced beta effect in these experimentally relevant cases. The resulting beta-improved core confinement should thus be considered for extrapolations to future machines.

  3. Video analysis of dust events in full-tungsten ASDEX Upgrade

    Science.gov (United States)

    Brochard, F.; Shalpegin, A.; Bardin, S.; Lunt, T.; Rohde, V.; Briançon, J. L.; Pautasso, G.; Vorpahl, C.; Neu, R.; The ASDEX Upgrade Team

    2017-03-01

    Fast video data recorded during seven consecutive operation campaigns (2008-2012) in full-tungsten ASDEX Upgrade have been analyzed with an algorithm developed to automatically detect and track dust particles. A total of 2425 discharges have been analyzed, corresponding to 12 204 s of plasma operation. The analysis aimed at precisely identifying and sorting the discharge conditions responsible of the dust generation or remobilization. Dust rates are found to be significantly lower than in tokamaks with carbon PFCs. Significant dust events occur mostly during off-normal plasma phases such as disruptions and particularly those preceded by vertical displacement events (VDEs). Dust rates are also increased but to a lower extent during type-I ELMy H-modes. The influences of disruption energy, heating scenario, vessel venting and vessel vibrations are also presented.

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

    Science.gov (United States)

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

    2016-11-01

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

  5. 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.

  6. 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.

  7. 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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-10-15

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

  9. 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.

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

    Science.gov (United States)

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

    2017-02-01

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

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

    Science.gov (United States)

    Jaulmes, F.; Geiger, B.; Odstrčil, T.; Weiland, M.; Salewski, M.; Jacobsen, A. S.; Rasmussen, J.; Stejner, M.; Nielsen, S. K.; Westerhof, E.; the EUROfusion MST1 Team; the ASDEX Upgrade Team

    2016-11-01

    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 EBdyna_go code. This contribution aims at studying the behaviour of ions, both impurity and fast particles, in the pattern of reconnecting field lines during sawtoothing plasma experiments in the ASDEX Upgrade tokamak by using the newly developed numerical framework. Simulations of full reconnection with tungsten impurity that include the centrifugal force are achieved and recover the soft x-ray measurements. Based on this full-reconnection description of the sawtooth, a simple tool dedicated to estimate the duration of the reconnection is introduced. This work then studies the redistribution of fast ions during several experimentally observed sawteeth. In some cases of sawteeth at ASDEX Upgrade, full reconnection is not always observed or expected so the code gives an upper estimate of the actual experimental redistribution. The results of detailed simulations of the crashes are compared with measurements from various diagnostics such as collective Thomson scattering and fast-ion D-alpha (FIDA) spectroscopy, including FIDA tomography. A convincing qualitative agreement is found in different parts of velocity space.

  12. 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.)

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

    Science.gov (United States)

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

    2017-01-01

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

  14. ELM behavior in ASDEX Upgrade with and without nitrogen seeding

    Science.gov (United States)

    Frassinetti, L.; Dunne, M. G.; Beurskens, M.; Wolfrum, E.; Bogomolov, A.; Carralero, D.; Cavedon, M.; Fischer, R.; Laggner, F. M.; McDermott, R. M.; Meyer, H.; Tardini, G.; Viezzer, E.; the EUROfusion MST1 Team; the ASDEX-Upgrade Team

    2017-02-01

    The Type I ELM behavior in ASDEX Upgrade with full W plasma facing components is studied in terms of time scales and energy losses for a large set of shots characterized by similar operational parameters but different nitrogen seeding rate and input power. ELMs with no nitrogen can have two typical behaviors, that can be classified depending on their duration, the long and the short ELMs. The work shows that both short and long ELMs have a similar first phase, but the long ELMs are characterized by a second phase with further energy losses. The second phase disappears when nitrogen is seeded with a flux rate above 1022 (e s-1). The phenomenon is compatible with a threshold effect. The presence of the second phase is related to a high divertor/scrape-off layer (SOL) temperature and/or to a low pedestal temperature. The ELM energy losses of the two phases are regulated by different mechanisms. The energy losses of the first phase increase with nitrogen which, in turn, produce the increase of the pedestal temperature. So the energy losses of the first phase are regulated by the pedestal top parameters and the increase with nitrogen is due to the decreasing pedestal collisionality. The energy losses of the second phase are related to the divertor/SOL conditions. The long ELMs energy losses increase with increasing divertor temperature and with the number of the expelled filaments. In terms of the power lost by the plasma, the nitrogen seeding increases the power losses of the short ELMs. The long ELMs have a first phase with power losses comparable to the short ELMs losses. Assuming no major difference in the wetted area, these results suggest that (i) the nitrogen might increase the divertor heat fluxes during the short ELMs and that (ii) the long ELMs, despite the longer time scale, are not beneficial in terms of divertor heat loads.

  15. 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.

  16. Long term project in ASDEX upgrade: Implementation of ferritic steel as in vessel wall

    Energy Technology Data Exchange (ETDEWEB)

    Zammuto, I., E-mail: irene.zammuto@ipp.mpg.de [Max-Planck-Institut für Plasmaphysik, D-85740 Garching (Germany); Giannone, L. [Max-Planck-Institut für Plasmaphysik, D-85740 Garching (Germany); Houben, A. [Institute of Energy and Climate Research, Plasma Physics, Forschungszentrum Jülich GmbH, Trilateral Euregio Cluster, 52425 Jülich (Germany); Herrmann, A.; Kallenbach, A. [Max-Planck-Institut für Plasmaphysik, D-85740 Garching (Germany)

    2015-10-15

    A long term project is started at the ASDEX Upgrade (AUG) tokamak aimed at the exploration of the compatibility of reduced activation ferritic/martensitic steel (RAFM) with fusion devices. The topic is oriented toward the preparation of future experiments such as ITER with its test blanket modules and DEMO with its first wall designed with RAFM. The goal of the project is to gather experience with ferromagnetic materials inside the vacuum vessel, dealing with magnetic perturbations, both in plasma and magnetic probes, and facing up the additional magnetic forces acting on the supporting structures. The project envisages a stepwise replacement of the traditional graphite tiles with ferritic steel. For the time being, the main AUG actor is the inner heat shield (IHS), but further development can be imagined in the future. Since 2013, two of the 15 tile rows of the IHS have been replaced with ferritic steel and since now the experimental campaign has not suffered any particular problem related to the perturbation field induced by the steel tiles, as predicted by the calculation. In the present paper, the preliminary study accomplished for the first phase for the evaluation of the forces and magnetic perturbation is reported, together with the further calculations required for the extension of the steel wall.

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

    Science.gov (United States)

    Křivská, A.; Bobkov, V.; Colas, L.; Jacquot, J.; Milanesio, D.; Ochoukov, R.

    2015-12-01

    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.

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

    Science.gov (United States)

    Chernyshova, M.; Malinowski, K.; Czarski, T.; Wojeński, A.; Vezinet, D.; Poźniak, K. T.; Kasprowicz, G.; Mazon, D.; Jardin, A.; Herrmann, A.; Kowalska-Strzeciwilk, E.; Krawczyk, R.; Kolasiński, P.; Zabołotny, W.; Zienkiewicz, P.

    2016-11-01

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

  19. 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...

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

    DEFF Research Database (Denmark)

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

    2011-01-01

    to a simple model, motivated by observations. A new diagnostic in the form of a reciprocating probe with three magnetic pickup loops was developed for ASDEX Upgrade (AUG). Measurements during the passage of type-I ELM filaments determine the filaments to be in the scrape off layer (SOL) and to carry currents...

  1. 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..

    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...

  2. 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...

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

    DEFF Research Database (Denmark)

    Michelsen, S.; Korsholm, Søren Bang; Bindslev, H.

    2004-01-01

    spectral channels at TEXTOR and 50 spectral channels at ASDEX Upgrade. The antenna patterns of probe and receiver, both steerable, determine size and location of the measuring volume, and the direction of the resolved fast ion velocity. With overmoded transmission lines, consisting of waveguides...

  4. Assessment of SOLPS5.0 divertor solutions with drifts and currents against L-mode experiments in ASDEX Upgrade and JET

    Science.gov (United States)

    Aho-Mantila, L.; Potzel, S.; Coster, D. P.; Wischmeier, M.; Brix, M.; Fischer, R.; Marsen, S.; Meigs, A.; Müller, H. W.; Scarabosio, A.; Stamp, M. F.; Brezinsek, S.; the ASDEX Upgrade Team; JET Contributors, the

    2017-03-01

    The divertor solutions obtained with the plasma edge modelling tool SOLPS5.0 are discussed. The code results are benchmarked against carefully analysed L-mode discharges at various density levels with and without impurity seeding in the full-metal tokamaks ASDEX Upgrade and JET. The role of the cross-field drifts and currents in the solutions is analysed in detail, and the improvements achieved by fully activating the drift and current terms in view of matching the experimental signals are addressed. The persisting discrepancies are also discussed.

  5. 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

  6. 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 rad...... 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....

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

    DEFF Research Database (Denmark)

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

    2009-01-01

    In ASDEX Upgrade (AUG) electrostatic and magnetic fluctuations in the edge plasma region were measured simultaneously during ELMy H-mode (high confinement) plasmas and L-mode (low confinement) plasmas and during a transition between the two modes. A special probe was used containing six Langmuir ...... into the scrape-off layer outside the last closed flux surface. The main emphasis is put on type I ELMs and from the results the radial turbulent particle flux and magnetic field variations are determined....

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-11-15

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

  9. 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.

  10. 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.;

    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...

  11. 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.

  12. 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.

  13. The I-mode confinement regime at ASDEX Upgrade: global properties and characterization of strongly intermittent density fluctuations

    Science.gov (United States)

    Happel, T.; Manz, P.; Ryter, F.; Bernert, M.; Dunne, M.; Hennequin, P.; Hetzenecker, A.; Stroth, U.; Conway, G. D.; Guimarais, L.; Honoré, C.; Viezzer, E.; The ASDEX Upgrade Team

    2017-01-01

    Properties of the I-mode confinement regime on the ASDEX Upgrade tokamak are summarized. A weak dependence of the power threshold for the L-I transition on the toroidal magnetic field strength is found. During improved confinement, the edge radial electric field well deepens. Stability calculations show that the I-mode pedestal is peeling-ballooning stable. Turbulence investigations reveal strongly intermittent density fluctuations linked to the weakly coherent mode in the confined plasma, which become stronger as the confinement quality increases. Across all investigated structure sizes ({{k}\\bot}≈ 5 -12 cm-1, with {{k}\\bot} the perpendicular wavenumber of turbulent density fluctuations), the intermittent turbulence bursts are observed. Comparison with bolometry data shows that they move poloidally toward the X-point and finally end up in the divertor. This might be indicative that they play a role in inhibiting the density profile growth, such that no pedestal is formed in the edge density profile.

  14. Interplay between turbulence, neoclassical and zonal flows during the transition from low to high confinement mode at ASDEX Upgrade

    Science.gov (United States)

    Cavedon, M.; Pütterich, T.; Viezzer, E.; Birkenmeier, G.; Happel, T.; Laggner, F. M.; Manz, P.; Ryter, F.; Stroth, U.; The ASDEX Upgrade Team

    2017-01-01

    The spatio-temporal interplay between turbulence, mean and zonal flows has been investigated at the L-H and H-L transitions in the edge region of the ASDEX Upgrade tokamak. Close to both transitions, an intermediate phase (I-phase) characterized by ‘limit cycle like oscillations’ (LCOs) is observed in which periodic bursts of turbulence correlate with \\mathbf{E}× \\mathbf{B} flow reduction and relaxation of gradients. During the I-phase, the \\mathbf{E}× \\mathbf{B} velocity is dominated by the mean flows indicating that turbulence driven flows are small. Periodic dithers between L-mode and the phases with LCOs are also observed just before the H-mode onset where the edge density and temperature profile gradients evolve on similar timescale as the flows. Thus connection between mean and \\mathbf{E}× \\mathbf{B} flows holds during the all evolution from L-mode to H-mode demonstrating the fundamental role of the neoclassical flows in the L-H transition physics.

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

    Energy Technology Data Exchange (ETDEWEB)

    Mlynek, Alexander

    2010-07-20

    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 2{pi} 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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-10-15

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

  17. Avoidance of disruptions at high βN in ASDEX Upgrade with off-axis ECRH

    Science.gov (United States)

    Esposito, B.; Granucci, G.; Maraschek, M.; Nowak, S.; Gude, A.; Igochine, V.; Lazzaro, E.; McDermott, R.; Poli, E.; Stober, J.; Suttrop, W.; Treutterer, W.; Zohm, H.; Brunetti, D.; ASDEX Upgrade Team

    2011-08-01

    Experiments on disruption avoidance have been carried out in H-mode ASDEX Upgrade plasmas: the localized perpendicular injection of ECRH (1.5 MW ~ 0.2Ptot) onto the q = 2 resonant surface has led to the delay and/or complete avoidance of disruptions in a high βN scenario (Ip = 1 MA, Bt = 2.1 T, q95 ~ 3.6, with NBI ~7.5 MW). In these discharges (at low q95 and low density) neoclassical tearing modes (NTMs) are excited: the growth and locking of the m/n = 2/1 mode leads to the disruption. The scheme of the experiment is successfully applied in the same way as in previous disruption avoidance experiments in FTU and ASDEX Upgrade. As soon as the disruption precursor signal (the locked mode detector and/or the loop voltage) reaches the preset threshold, the ECRH power is triggered by real-time control. A poloidal scan in deposition location (ρdep) has been carried out by setting the poloidal launching mirrors at different angles in each discharge. The results depend on ρdep: complete disruption avoidance can be achieved when the power is injected close to or onto the 2/1 island. When ECRH is injected outside the island (either at radii inside or outside the q = 2 surface), the discharge is disrupted as in the reference case.

  18. 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.

  19. ICRF antennas optimized for operation with a high-Z metallic wall in ASDEX Upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Zammuto, I. [Euratom Association, Max Planck-Institut fuer Plasmaphysik, Boltzmannstrasse 2, D-85748 Garching (Germany)], E-mail: i.zammuto@libero.it; Krivska, A. [Euratom Association, Institute of Plasma Physics ASCR, Prague (Czech Republic); Telecommunication Engineering Department, Czech Technical University of Prague, Prague (Czech Republic); Bobkov, V.; Braun, F.; Bilato, R. [Euratom Association, Max Planck-Institut fuer Plasmaphysik, Boltzmannstrasse 2, D-85748 Garching (Germany); Noterdaeme, J.-M. [Euratom Association, Max Planck-Institut fuer Plasmaphysik, Boltzmannstrasse 2, D-85748 Garching (Germany); EESA Department, University of Gent, Gent (Belgium)

    2009-06-15

    High-Z materials are considered the best candidates for plasma facing components (PFCs) in future fusion devices, while ion cyclotron range of frequencies (ICRF) heating is a method of choice because of its flexibility, cost effectiveness, and plug-to-power efficiency. But high-Z materials and ICRF have been a difficult combination. ASDEX Upgrade (AUG) is pioneering the use of a tungsten (W) wall and in the next years it will prove (or disprove) the appropriateness of this combination for the future. This paper describes the optimization procedure for and the main features of a new proposed ICRF antenna for AUG specifically designed to improve the compatibility of ICRF with a high-Z metallic wall. The optimization criteria for a new design are based on a reduction of the parasitic parallel electric field responsible of the impurity production. The evolutionary design of the 2-strap antenna is compared with a redesigned 4-strap antenna embedded in the wall. Moreover, options and constraints on how to integrate a wider antenna in the present configuration of ASDEX Upgrade and its integration on the stabilizing wall are discussed.

  20. Measurements and modeling of Alfven eigenmode induced fast ion transport and loss in DIII-D and ASDEX Upgrade

    NARCIS (Netherlands)

    VanZeeland, M. A.; Heidbrink, W. W.; Fisher, R. K.; Munoz, M. G.; Kramer, G. J.; Pace, D. C.; White, R. B.; Akaslompolo, S.; Austin, M. E.; Boom, J. E.; Classen, I.G.J.; da Graca, S.; Geiger, B.; Gorelenkova, M.; Gorelenkov, N. N.; Hyatt, A. W.; Luhmann, N.; Maraschek, M.; McKee, G. R.; Moyer, R. A.; Muscatello, C. M.; Nazikian, R.; Park, H.; Sharapov, S.; Suttrop, W.; Tardini, G.; Tobias, B. J.; Zhu, Y. B.

    2011-01-01

    Neutral beam injection into reversed magnetic shear DIII-D and ASDEX Upgrade plasmas produces a variety of Alfvenic activity including toroidicity-induced Alfven eigenmodes and reversed shear Alfven eigenmodes (RSAEs). These modes are studied during the discharge current ramp phase when incomplete c

  1. On the determination of the poloidal velocity and the shear layer in the SOL of ASDEX Upgrade

    DEFF Research Database (Denmark)

    Mehlmann, F.; Costea, S.; Naulin, Volker

    A reciprocating probe with six pins was used for localized measurements in the scrape-off layer (SOL) of ASDEX Upgrade (AUG) up to the shear layer (SL) and a few mm inside it. The probe was used to determine the poloidal velocity with three different methods which are critically compared to each...

  2. 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.

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

    Science.gov (United States)

    Orain, F.; Hölzl, M.; Viezzer, E.; Dunne, M.; Bécoulet, M.; Cahyna, P.; Huijsmans, G. T. A.; Morales, J.; Willensdorfer, M.; Suttrop, W.; Kirk, A.; Pamela, S.; Günter, S.; Lackner, K.; Strumberger, E.; Lessig, A.; the ASDEX Upgrade Team; the EUROfusion MST1 Team

    2017-02-01

    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 kink component (m  >  nq) 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 amplification can only partly explain the density pumpout observed in experiments.

  4. Disruption mitigation by injection of small quantities of noble gas in ASDEX Upgrade

    Science.gov (United States)

    Pautasso, G.; Bernert, M.; Dibon, M.; Duval, B.; Dux, R.; Fable, E.; Fuchs, J. C.; Conway, G. D.; Giannone, L.; Gude, A.; Herrmann, A.; Hoelzl, M.; McCarthy, P. J.; Mlynek, A.; Maraschek, M.; Nardon, E.; Papp, G.; Potzel, S.; Rapson, C.; Sieglin, B.; Suttrop, W.; Treutterer, W.; The ASDEX Upgrade Team; The EUROfusion MST1 Team

    2017-01-01

    The most recent experiments of disruption mitigation by massive gas injection in ASDEX Upgrade have concentrated on small—relatively to the past—quantities of noble gas injected, and on the search for the minimum amount of gas necessary for the mitigation of the thermal loads on the divertor and for a significant reduction of the vertical force during the current quench. A scenario for the generation of a long-lived runaway electron beam has been established; this allows the study of runaway current dissipation by moderate quantities of argon injected. This paper presents these recent results and discusses them in the more general context of physical models and extrapolation, and of the open questions, relevant for the realization of the ITER disruption mitigation system.

  5. 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

    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......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...... 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...

  6. In-out divertor flow asymmetries during ELMs in ASDEX Upgrade H-mode plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Tsalas, M. [NCSR ' Demokritos' , Institute of Nuclear Technology - Radiation Protection, 153 10 Aghia Paraskevi, Attica (Greece) and EDFA-JET CSU, Abingdon OX14 3DB, Oxon (United Kingdom)]. E-mail: maximos@ipta.demokritos.gr; Coster, D. [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, Garching (Germany); Fuchs, C. [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, Garching (Germany); Herrmann, A. [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, Garching (Germany); Kallenbach, A. [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, Garching (Germany); Mueller, H.W. [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, Garching (Germany); Neuhauser, J. [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, Garching (Germany); Rohde, V. [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, Garching (Germany); Tsois, N. [NCSR ' Demokritos' , Institute of Nuclear Technology - Radiation Protection, 153 10 Aghia Paraskevi, Attica (Greece)

    2007-06-15

    In ASDEX Upgrade, a fast reciprocating probe positioned in the lower divertor, capable of accessing the low-field side (LFS) and high-field side (HFS) scrape-off layer (SOL) just below the x-point, as well as the private flux region, was equipped with a Mach head and used to investigate fast flow fluctuations and in-out divertor flow asymmetries during ELMs. We compare the flow behaviour during ELMs in the three separate regions. Flow enhancement is observed in the HFS SOL, with Mach number values reaching or exceeding M = 2, flow reversal in the LFS SOL, and complex fluctuating behaviour in the private flux region (which includes flow reversal). We discuss the possible mechanisms that could drive these observations.

  7. 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.

  8. Gyrokinetic studies of core turbulence features in ASDEX Upgrade H-mode plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Navarro, A. Bañón, E-mail: banon@physics.ucla.edu; Told, D. [Max-Planck-Institut für Plasmaphysik, Boltzmannstrase 2, 85748 Garching (Germany); Department of Physics and Astronomy, University of California, Los Angeles, California 90095 (United States); Happel, T.; Görler, T.; Abiteboul, J.; Bustos, A.; Doerk, H. [Max-Planck-Institut für Plasmaphysik, Boltzmannstrase 2, 85748 Garching (Germany); Jenko, F. [Max-Planck-Institut für Plasmaphysik, Boltzmannstrase 2, 85748 Garching (Germany); Department of Physics and Astronomy, University of California, Los Angeles, California 90095 (United States); Max-Planck/Princeton Center for Plasma Physics (United States)

    2015-04-15

    Gyrokinetic validation studies are crucial for developing confidence in the model incorporated in numerical simulations and thus improving their predictive capabilities. As one step in this direction, we simulate an ASDEX Upgrade discharge with the GENE code, and analyze various fluctuating quantities and compare them to experimental measurements. The approach taken is the following. First, linear simulations are performed in order to determine the turbulence regime. Second, the heat fluxes in nonlinear simulations are matched to experimental fluxes by varying the logarithmic ion temperature gradient within the expected experimental error bars. Finally, the dependence of various quantities with respect to the ion temperature gradient is analyzed in detail. It is found that density and temperature fluctuations can vary significantly with small changes in this parameter, thus making comparisons with experiments very sensitive to uncertainties in the experimental profiles. However, cross-phases are more robust, indicating that they are better observables for comparisons between gyrokinetic simulations and experimental measurements.

  9. 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.

  10. Making ICRF power compatible with a high-Z wall in ASDEX Upgrade

    Science.gov (United States)

    Bobkov, V.; Aguiam, D.; Bilato, R.; Brezinsek, S.; Colas, L.; Faugel, H.; Fünfgelder, H.; Herrmann, A.; Jacquot, J.; Kallenbach, A.; Milanesio, D.; Maggiora, R.; Neu, R.; Noterdaeme, J.-M.; Ochoukov, R.; Potzel, S.; Pütterich, T.; Silva, A.; Tierens, W.; Tuccilo, A.; Tudisco, O.; Wang, Y.; Yang, Q.; Zhang, W.; ASDEX Upgrade Team; the EUROfusion MST1 Team

    2017-01-01

    A comparison of the ASDEX Upgrade 3-strap ICRF antenna data with the linear electro-magnetic TOPICA calculations is presented. The comparison substantiates a reduction of the local electric field at the radially protruding plasma-facing elements of the antenna as a relevant approach for minimizing tungsten (W) sputtering in conditions when the slow wave is strongly evanescent. The measured reaction of the time-averaged RF current at the antenna limiters to the antenna feeding variations is less sensitive than predicted by the calculations. This is likely to have been caused by temporal and spatial fluctuations in the 3D plasma density distribution affected by local non-linear interactions. The 3-strap antenna with the W-coated limiters produces drastically less W sputtering compared to the W-coated 2-strap antennas. This is consistent with the non-linear asymptotic SSWICH-SW calculations for RF sheaths.

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

    Energy Technology Data Exchange (ETDEWEB)

    Varela, P.; Manso, M. [Associacao EURATOM/IST, Centro de Fusao Nuclear, Instituto Superior Tecnico, Lisboa (Portugal); Conway, G. [Max-Planck-Instituet fuer Plasmaphysik, EURATOM Association, Garching (Germany)

    2001-05-01

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

  12. 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

  13. 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

  14. 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...

  15. Electric probe measurements of the poloidal velocity in the scrape-off layer of ASDEX upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Mehlmann, F.; Costea, S.; Schrittwieser, R.; Lux, C.; Ionita, C. [Institute for Ion Physics and Applied Physics, University of Innsbruck, Association EURATOM/OeAW (Austria); Naulin, V.; Rasmussen, J.J.; Nielsen, A.H. [Association EURATOM-DTU, Dept. of Physics, Technical University of Denmark, Lyngby (Denmark); Mueller, H.W.; Carralero, D.; Rohde, V. [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, Garching (Germany); Vianello, N. [Consorzio RFX, Associazione Euratom-ENEA sulla Fusione, Padova (Italy); Collaboration: ASDEX Upgrade Team

    2014-04-15

    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 vθ 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{sub r} measured by two radially staggered probe pins, with vθ being due to the E{sub r} x B{sub φ}-drift (B{sub φ} 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 correlation were used to determine the poloidal velocity and its jump, yielding comparable results to the first method. Also the method of conditional averaging was applied to the latter signals. (copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  16. 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.

  17. 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.

  18. ASDEX Upgrade Edge Transport Studies by Turbulence and Braginskii Divertor Transport Codes

    Energy Technology Data Exchange (ETDEWEB)

    Nishimura, Y.; Coster, D.P.; Kim, J.W.; Scott, B.D. [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, Garching (Germany)

    2001-07-01

    The equilibration time for diverter transport simulations is in the range of milliseconds to seconds. There, perpendicular transport is given empirically and usually assumed to be constant in time and space. In this work, we aim at describing edge plasma profiles in both the H-mode and the L-mode confinement regimes using a model that couples the transport scale to the underlying turbulence scale. There are 2d and 3d variants of DALF, which is a turbulence code that describes short time scale nonlinear phenomena based on first principles of plasma physics. B2 employs an implicit method which is suitable for describing long time scale, quasi-steady state behavior, while fluctuation/intermittency is inherent in turbulence and typically gives rise to short time scale variations of the radial flux. We coarse rained the information from the 2d version of DALF within the order of turbulence auto correlation time and iterated over the divertor simulation (and thus passed plasma parameters to the turbulence code). Numerical algorithm and criteria for convergence in bridging the physics of two different scales is discussed. The generation mechanism of radial electric field in steep gradient regimes is revisited in the ASDEX Upgrade divertor geometry with realistic parameters. Inclusion of turbulent suppression effects by E x B shear flow is considered. (orig.)

  19. Design and concept validation of the new solid tungsten divertor for ASDEX Upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Herrmann, A., E-mail: albrecht.herrmann@ipp.mpg.de; Greuner, H.; Jaksic, N.; Böswirth, B.; Reimold, F.; Scarabosio, A.; Vorbrugg, S.; Wischmeier, M.

    2013-10-15

    Div-III, a divertor with solid tungsten target tiles for ASDEX Upgrade is designed and tested and will be installed in 2013. It is a further step in exploring tungsten as material for plasma facing components. It avoids the restrictions of tungsten coatings on graphite and realizes an operation range up to 50 MJ energy removing capability in the outer divertor. In addition, it allows physics investigation such as erosion and deuterium retention as well as effects of castellation and target tilting. The design of the target itself and the attachment was optimized with FE-analysis and was intensively high heat tested up to a double overload. Cyclic tests reveal that the target and the attachment can be operated with the design load of 50 MJ without any damage. Even a twofold overload results in local recrystallization and minor cracks but the targets did not fail during operation. The redesign of the divertor structure was used to increase the conductance between the cryo-pump and the divertor region. The impact of the changed pumping efficiency was investigated with SOLPS/Eirene modeling. The modeling results are an indication for an easier access to lower SOL densities as expected for a higher pumping efficiency in the main chamber.

  20. Filament transport, warm ions and erosion in ASDEX Upgrade L-modes

    Science.gov (United States)

    Birkenmeier, G.; Manz, P.; Carralero, D.; Laggner, F. M.; Fuchert, G.; Krieger, K.; Maier, H.; Reimold, F.; Schmid, K.; Dux, R.; Pütterich, T.; Willensdorfer, M.; Wolfrum, E.; The ASDEX Upgrade Team

    2015-03-01

    The dynamics of blob filaments are investigated in the scrape-off layer of ASDEX Upgrade by means of lithium beam emission spectroscopy. A comparison of the measurements in L-mode with a recently developed analytical blob model based on a drift-interchange-Alfvén fluid model indicates an influence of a finite ion temperature on the blob dynamics which has typically been neglected in other blob models. The blob dynamics agree well with the sheath-connected regime at lower plasma densities, and inertial effects play only a minor role. At higher densities, a transition into another regime with large blob amplitudes and increased transport is found. This points to a prominent role of blob transport at higher Greenwald fractions. On the basis of the measured blob properties, the erosion on plasma facing components is estimated. For pure deuterium plasmas, the high ion temperatures of blobs lead to a dominant erosion induced by blobs. However, if an impurity concentration of 1% is taken into account, the blob-induced erosion plays a minor role and background plasma parameters determine the total gross erosion.

  1. 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.

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

    Science.gov (United States)

    Schneider, P A; Blank, H; Geiger, B; Mank, K; Martinov, S; Ryter, F; Weiland, M; Weller, A

    2015-07-01

    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.

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

    Science.gov (United States)

    Schneider, P. A.; Blank, H.; Geiger, B.; Mank, K.; Martinov, S.; Ryter, F.; Weiland, M.; Weller, A.

    2015-07-01

    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.

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

    DEFF Research Database (Denmark)

    Bin, W.; Bruschi, A.; D'Arcangelo, O.;

    2015-01-01

    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 i...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-10-15

    Highlights: • The main motivation for the HHF investigation of tungsten tiles was an untypical deformation of some specimens under thermal loading, observed during the previous tests in GLADIS test facility. • A nonlinear finite element (FE) model for simulations of the GLADIS tests has been built. • The unexpected plastic deformations are mainly caused by internal stresses due to the manufacturing process. The small discrepancies among the FEA investigated and measured plastic deformations are most likely caused, beside of the practical difficulties by measuring of low items, also by tile internal stresses. • The influences of the residual stresses caused by special production processes have to be taken into account by design of the structural part made of solid tungsten. - Abstract: Tungsten as plasma-facing material for fusion devices is currently the most favorable candidate. In general solid tungsten is used for shielding the plasma chamber interior against the high heat generated from the plasma. For the purposes of implementation at ASDEX Upgrade and as a contribution to ITER the thermal performance of tungsten tiles has been extensively tested in the high heat flux test facility GLADIS during the development phase and beyond. These tests have been performed on full scale tungsten tile prototypes including their clamping and cooling structure. Simulating the adiabatically thermal loading due to plasma operation in ASDEX Upgrade, the tungsten tiles have been subjected to a thermal load with central heat flux of 10–24 MW/m{sup 2} and absorbed energy between 370 and 680 kJ. This loading results in maximum surface temperatures between 1300 °C and 2800 °C. The tests in GLADIS have been accompanied by intensive numerical investigations using FEA methods. For this purpose a multiple nonlinear finite element model has been set up. This paper discusses the main results of the high heat flux final tests and their numerical simulation. Moreover, first

  6. 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.

  7. 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.

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

    DEFF Research Database (Denmark)

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

    2013-01-01

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

  9. How to upgrade a control system for a tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Tenten, W. (Zentrallabor fuer Elektronik, Forschungszentrum Juelich GmbH (KFA), 52425 Juelich (Germany)); Dohms, U. (Zentrallabor fuer Elektronik, Forschungszentrum Juelich GmbH (KFA), 52425 Juelich (Germany)); Fuss, L. (Zentrallabor fuer Elektronik, Forschungszentrum Juelich GmbH (KFA), 52425 Juelich (Germany)); Huppertz, H. (Zentrallabor fuer Elektronik, Forschungszentrum Juelich GmbH (KFA), 52425 Juelich (Germany)); Lerch, J. (Zentrallabor fuer Elektronik, Forschungszentrum Juelich GmbH (KFA), 52425 Juelich (Germany)); Mueller, K.D. (Zentrallabor fuer Elektronik, Forschungszentrum Juelich GmbH (KFA), 52425 Juelich (Germany)); Reinhart, P. (Zentrallabor fuer Elektronik, Forschungszentrum Juelich GmbH (KFA), 52425 Juelich (Germany)); Rongen, F. (Zentrallabor fuer Elektronik, Forschungszentrum Juelich GmbH (KFA), 52425 Juelich (Germany))

    1994-12-15

    The TEXTOR tokamak for technology-oriented research in Juelich has been in operation since 1981. Its control system consists basically of a CAMAC computer system (PDP-11) for remote control and display, linked to programmable controllers (SIEMENS S3) for subsystem control via fibre optic cables. Due to several reasons, an upgrade of this well-established control system has become unavoidable. The main objective for this process is to provide better availability and reliability for another decade of operation and to reduce maintenance costs significantly. In this respect all CAMAC instrumentation had to be preserved completely. The paper describes in detail the background, design and layout of the new control system. Because upgrading an existing control system substantially differs from constructing a new system for a new device, special attention is given to the steps of achieving a smooth upgrade procedure that avoids unnecessary interferences with the TEXTOR operation. ((orig.))

  10. Comparison between 2D turbulence model ESEL and experimental data from AUG and COMPASS tokamaks

    DEFF Research Database (Denmark)

    Ondac, Peter; Horacek, Jan; Seidl, Jakub;

    2015-01-01

    In this article we have used the 2D fluid turbulence numerical model, ESEL, to simulate turbulent transport in edge tokamak plasma. Basic plasma parameters from the ASDEX Upgrade and COMPASS tokamaks are used as input for the model, and the output is compared with experimental observations obtained...

  11. Compatibility of ITER scenarios with full tungsten wall in ASDEX Upgrade

    Science.gov (United States)

    Gruber, O.; Sips, A. C. C.; Dux, R.; Eich, T.; Fuchs, J. C.; Herrmann, A.; Kallenbach, A.; Maggi, C. F.; Neu, R.; Pütterich, T.; Schweinzer, J.; Stober, J.; ASDEX Upgrade Team

    2009-11-01

    The transition of ASDEX Upgrade (AUG) from a graphite device to a full tungsten device is demonstrated with a reduction by an order of magnitude in both the carbon deposition and deuterium retention. The tungsten source is dominated by sputtering from intrinsic light impurities, and the tungsten influxes from the outboard limiters are the main source for the plasma. In H-mode discharges, central heating (neutral beams, ECRH) is used to increase turbulent outward transport avoiding tungsten accumulation. ICRH can only be used after boronization as its application otherwise results in large W influxes due to light impurities accelerated by electrical fields at the ICRH antennas. ELMs are important in reducing the inward transport of tungsten in the H-mode edge barrier and are controlled by gas puffing. Even without boronization, stationary, ITER baseline H-modes (confinement enhancement factor from ITER 98(y, 2) scaling H98 ~ 1, normalized beta βN ~ 2), with W concentrations below 3 × 10-5 were routinely achieved up to 1.2 MA plasma current. The compatibility of high performance improved H-modes with unboronized W wall was demonstrated, achieving H98 = 1.1 and βN up to 2.6 at modest triangularities δ cooled by N2 seeding. N2 seeding does not only protect the divertor tiles but also considerably improves the performance of improved H-mode discharges. The energy confinement increased to H98-factors of 1.25 (βN ~ 2.7) and thereby exceeded the best values in a carbon-dominated AUG machine under similar conditions. Recent investigations show that this improvement is due to higher temperatures rather than to peaking of the electron density profile. Further ITER discharge scenario tests include the demonstration of ECRF assisted low voltage plasma start-up and current rise to q95 = 3 at toroidal electric fields below 0.3 V m-1, to achieve a ITER compatible range of plasma internal inductance of 0.71-0.97. The results reported here strongly support tungsten as a first

  12. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-10-15

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

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

    Science.gov (United States)

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

    2004-11-01

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

  15. 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.

  16. Implementation of the new multichannel X-mode edge density profile reflectometer for the ICRF antenna on ASDEX Upgrade

    Science.gov (United States)

    Aguiam, D. E.; Silva, A.; Bobkov, V.; Carvalho, P. J.; Carvalho, P. F.; Cavazzana, R.; Conway, G. D.; D'Arcangelo, O.; Fattorini, L.; Faugel, H.; Fernandes, A.; Fünfgelder, H.; Gonçalves, B.; Guimarais, L.; De Masi, G.; Meneses, L.; Noterdaeme, J. M.; Pereira, R. C.; Rocchi, G.; Santos, J. M.; Tuccillo, A. A.; Tudisco, O.

    2016-11-01

    A new multichannel frequency modulated continuous-wave reflectometry diagnostic has been successfully installed and commissioned on ASDEX Upgrade to measure the plasma edge electron density profile evolution in front of the Ion Cyclotron Range of Frequencies (ICRF) antenna. The design of the new three-strap ICRF antenna integrates ten pairs (sending and receiving) of microwave reflectometry antennas. The multichannel reflectometer can use three of these to measure the edge electron density profiles up to 2 × 1019 m-3, at different poloidal locations, allowing the direct study of the local plasma layers in front of the ICRF antenna. ICRF power coupling, operational effects, and poloidal variations of the plasma density profile can be consistently studied for the first time. In this work the diagnostic hardware architecture is described and the obtained density profile measurements were used to track outer radial plasma position and plasma shape.

  17. 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.

  18. ECE RADIOMETER UPGRADE ON THE DIII-D TOKAMAK

    Energy Technology Data Exchange (ETDEWEB)

    AUSTIN, ME; LOHR, J

    2002-08-01

    OAK A271 ECE RADIOMETER UPGRADE ON THE DIII-D TOKAMAK. The electron cyclotron emission (ECE) heterodyne radiometer diagnostic on DIII-D has been upgraded with the addition of eight channels for a total of 40. The new, higher frequency channels allow measurements of electron temperature into the magnetic axis in discharges at maximum field, 2.15 T. The complete set now extends over the full usable range of second harmonic emission frequencies at 2.0 T covering radii from the outer edge inward to the location of third harmonic overlap on the high field side. Full coverage permits the measurement of heat pulses and magnetohydrodynamic (MHD) fluctuations on both sides of the magnetic axis. In addition, the symmetric measurements are used to fix the location of the magnetic axis in tokamak magnetic equilibrium reconstructions. Also, the new higher frequency channels have been used to determine central T{sub e} with good time resolution in low field, high density discharges using third harmonic ECE in the optically gray and optically thick regimes.

  19. 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...

  20. 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.

  1. Upgraded data service system for HT-7 Tokamak

    Institute of Scientific and Technical Information of China (English)

    QU Lian-Zheng; LUO Jia-Rong; WEI Pei-Jie; LI Gui-Ming; CHENG Ting; QI Na

    2005-01-01

    A data service system plays an indispensable role in HT-7 Tokamak experiment. Since the former system doesn't provide the function of timely data procession and analysis, and all client software are based on Windows, it can't fulfill virtual fusion laboratory for remote researchers. Therefore, a new system which is simplified by three kinds of data servers and one data analysis and visualization software tool has been developed. The data servers include a data acquisition server based on file system, an MDSplus server used as the central repository for analysis data, and a web server. Users who prefer the convenience of application that can be run in a Web Browser can easily access the experiment data without knowing X-Windows. In order to adjust instruments to control experiment the operators need to plot data duly as soon as they are gathered. To satisfy their requirement, an upgraded data analysis and visualization software GT-7 is developed. It not only makes 2D data visualization more efficient, but also it can be capable of processing, analyzing and displaying interactive 2D and 3D graph of raw, analyzed data by the format of ASCII, LZO and MDSplus.

  2. 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)

  3. Upgraded ECE radiometer on the Tore Supra Tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Segui, J.L.; Molina, D.; Goniche, M.; Maget, P.; Udintsev, V.S. [Association Euratom-CEA, Centre d' Etudes de Cadarache, 13 - Saint-Paul-lez-Durance (France). Dept. de Recherches sur la Fusion Controlee; Antar, G.Y. [Center for Energy Research, UCSD, La Jolla CA (United States); Kraemer-Flecken, A. [Forschungszentrum Juelich GmbH (Germany). Inst. fuer Plasmaphysik

    2004-07-01

    An upgraded 32-channel heterodyne radiometer, 1 GHz spaced, is used on the Tore-Supra tokamak to measure the electron cyclotron emission (ECE) in the frequency range 78-110 GHz for the ordinary mode (O1) and 94-126.5 GHz for the extraordinary mode (X2). From now radial resolution is essentially limited by ECE relativistic effects related to electron temperature and density, not by the channels frequency spacing. For example, this leads to precise electron temperature mapping during magneto hydrodynamic activities (MHD). In the equatorial plane, we use a dual polarisation Gaussian optics lens antenna. It has low spreading and a perpendicular line-of-sight that gives ECE measurements very low refraction and Doppler effects. Assuming that the plasma is a black body and there is no overlap between ECE harmonics, one can deduce the electron temperature profile by using the first harmonic ordinary mode (O1) or the second harmonic extraordinary mode (X2). The principle radio frequency emitter (RF) has its frequencies down shifted into intermediary frequencies (IF) that span from 2 to 18 GHz in the single side band mode (SSB). It is amplified by low noise IF amplifiers before forming channels. A separate O/X mode RF front-end allows the use of an IF electronic mode selector. This gives the potentiality of simultaneous O/X mode measurements in the 94-110 GHz. RF and IF filters reject the gyrotron frequency (118 GHz) in order to perform electron temperature measurements during electron cyclotron resonance heated plasmas. A precise absolute spectral calibration is performed outside the tokamak vacuum vessel by using a 600 deg C black body hot source, a double coherent digital signal averaging (trigger, turn and clock) on the waveform generated by a mechanical chopper, and a simulated tokamak window. The use of differential electronics and strong electromagnetic shielding improves also the calibration precision. The fast and slow data acquisition systems are free of aliasing

  4. Non-boronized compared with boronized operation of ASDEX Upgrade with full-tungsten plasma facing components

    Science.gov (United States)

    Kallenbach, A.; Dux, R.; Mayer, M.; Neu, R.; Pütterich, T.; Bobkov, V.; Fuchs, J. C.; Eich, T.; Giannone, L.; Gruber, O.; Herrmann, A.; Horton, L. D.; Maggi, C. F.; Meister, H.; Müller, H. W.; Rohde, V.; Sips, A.; Stäbler, A.; Stober, J.; ASDEX Upgrade Team

    2009-04-01

    After completion of the tungsten coating of all plasma facing components, ASDEX Upgrade has been operated without boronization for 1 1/2 experimental campaigns. This has allowed the study of fuel retention under conditions of relatively low D co-deposition with low-Z impurities as well as the operational space of a full-tungsten device for the unfavourable condition of a relatively high intrinsic impurity level. Restrictions in operation were caused by the central accumulation of tungsten in combination with density peaking, resulting in H-L backtransitions induced by too low separatrix power flux. Most important control parameters have been found to be the central heating power, as delivered predominantly by ECRH, and the ELM frequency, most easily controlled by gas puffing. Generally, ELMs exhibit a positive impact, with the effect of impurity flushing out of the pedestal region overbalancing the ELM-induced W source. The restrictions of plasma operation in the unboronized W machine occurred predominantly under low or medium power conditions. Under medium-high power conditions, stable operation with virtually no difference between boronized and unboronized discharges was achieved. Due to the reduced intrinsic radiation with boronization and the limited power handling capability of VPS coated divertor tiles (≈10 MW m-2), boronized operation at high heating powers was possible only with radiative cooling. To enable this, a previously developed feedback system using (thermo-)electric current measurements as approximate sensor for the divertor power flux was introduced into the standard AUG operation. To avoid the problems with reduced ELM frequency due to core plasma radiation, nitrogen was selected as radiating species since its radiative characteristic peaks at lower electron temperatures in comparison with Ne and Ar, favouring SOL and divertor radiative losses. Nitrogen seeding resulted not only in the desired divertor power load reduction but also in improved

  5. Optical emission measurements of H 2 and D 2 molecules in the divertor region of ASDEX Upgrade

    Science.gov (United States)

    Fantz, U.; Behringer, K.; Gafert, J.; Coster, D.; ASDEX Upgrade Team

    A spectroscopic method has been developed for measuring molecular influxes and particle densities in fusion edge plasmas, which is based on the H 2 and D 2 Fulcher emission bands around 600 nm wavelength. A first application to the ASDEX Upgrade divertor plasma is described. The influx of hydrogen molecules was determined from the population of the upper Fulcher state using the theoretical number of ionization and dissociation events per Fulcher photon ( Seff + Deff)/XB Ful, as calculated by a collisional-radiative model. These results were compared with expectations on the basis of the atomic hydrogen fluxes and a typical molecule/atom ratio. Measurements and calculations agree in their time dependence, but the experimental values are somewhat lower, which may be within the error margin or of more significance. The Fulcher radiation was also compared directly to B2-EIRENE predictions, resulting in a higher discrepancy. In addition, the vibrational population of the ground state molecules was determined from that of the excited state using a method based on Franck-Condon factors. It can be characterized by a Tvib between 3000 and 9000 K, inversely correlated with electron temperature. This variation is predicted by the collisional-radiative code and even allows an estimate of Te. Vibrational excitation increases ionization and dissociation rate coefficients, as clearly demonstrated by the code calculations. It is therefore very likely that the observed discrepancy in molecular intensity is mainly caused by the omission of vibrational excitation in the present version of B2-EIRENE. The described flux measurements are expected to be accurate above Te=5 eV, but are more difficult at lower temperatures due to the strong Te dependence of ( Seff + Deff)/XB Ful in that region.

  6. Convective and Diffusive Energetic Particle Losses Induced by Shear Alfven Waves in the ASDEX Upgrade Tokamak

    NARCIS (Netherlands)

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

    2010-01-01

    We present here the first phase-space characterization of convective and diffusive energetic particle losses induced by shear Alfven waves in a magnetically confined fusion plasma. While single toroidal Alfven eigenmodes (TAE) and Alfven cascades (AC) eject resonant fast ions in a convective process

  7. A new thermal He-beam diagnostic for electron density and temperature measurements in the scrape-off layer of ASDEX Upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Griener, Michael; Wolfrum, Elisabeth; Eich, Thomas; Herrmann, Albrecht; Rohde, Volker [Max Planck Institute for Plasma Physics, Garching (Germany); Schmitz, Oliver [Engineering Physics Department, University of Wisconsin-Madison (United States); Stroth, Ulrich [Max Planck Institute for Plasma Physics, Garching (Germany); Physik Department E28, Technische Universitaet Muenchen, Garching (Germany); Collaboration: the ASDEX Upgrade Team

    2015-05-01

    In a nuclear fusion device power is exhausted across the last closed flux surface into the so-called 'scrape-off layer', SOL. In order to study the transport dynamics to (a) the divertor via parallel heat flux and (b) to the wall via filaments, a diagnostic for the determination of n{sub e} and T{sub e} with high spatial and temporal resolution is required. Although the diagnostic capabilities of the ASDEX Upgrade edge plasma are excellent, there is a lack of spatially and temporally highly resolved electron temperature measurements in the SOL. Therefore a piezo valve will be installed in ASDEX Upgrade in April 2015. It allows fast chopping of a thermal He-beam which is part of the new diagnostic. In the first campaign, existing lines of sight of the CXRS diagnostic will be used to measure various He I transitions to confirm the collisional radiative model for He. The principle of the thermal He-diagnostic as well as calculations of the achievable spatial resolution of the initial set-up are presented.

  8. 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

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

    Science.gov (United States)

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

    2015-03-01

    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 independent heterodyne receiver systems enables subtraction of the additional part from the total spectrum, revealing the resulting CTS spectrum. Here we present CTS measurements from the plasma centre obtained in L-mode and H-mode plasmas with and without neutral beam injection (NBI). For the first time, the measured spectra agree quantitatively with the synthetic spectra in periods with and without NBI heating. For the discharges investigated, the central velocity distribution of neutral beam ions can be described by classical slowing down. These results will have a major impact on ITER physics exploration, since CTS is presently the only diagnostic to measure the confined alpha particles produced by the fusion reactions.

  10. Note: Upgrade of electron cyclotron emission imaging system and preliminary results on HL-2A tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, M., E-mail: jiangm@swip.ac.cn; Shi, Z. B.; Zhong, W. L.; Chen, W.; Liu, Z. T.; Ding, X. T.; Yang, Q. W.; Zhang, B. Y.; Shi, P. W.; Liu, Y.; Fu, B. Z.; Xu, Y. [Southwestern Institute of Physics, P.O. Box 432, Chengdu 610041 (China); Domier, C. W.; Luhmann, N. C. [Department of Electrical and Computer Engineering, University of California, Davis, California 95616 (United States); Yang, Z. C. [School of Physics and Chemistry, Xihua University, Chengdu 610039 (China)

    2015-07-15

    The electron cyclotron emission imaging system on the HL-2A tokamak has been upgraded to 24 (poloidally) × 16 (radially) channels based on the previous 24 × 8 array. The measurement region can be flexibly shifted due to the independence of the two local oscillator sources, and the field of view can be adjusted easily by changing the position of the zoom lenses. The temporal resolution is about 2.5 μs and the achievable spatial resolution is 1 cm. After laboratory calibration, it was installed on HL-2A tokamak in 2014, and the local 2D mode structures of MHD activities were obtained for the first time.

  11. Upgrade of plasma density feedback control system in HT-7 tokamak

    Institute of Scientific and Technical Information of China (English)

    ZHAO Da-Zheng; LUO Jia-Rong; LI Gang; JI Zhen-Shan; WANG Feng

    2004-01-01

    The HT-7 is a superconducting tokamak in China used to make researches on the controlled nuclear fusion as a national project for the fusion research. The plasma density feedback control subsystem is the one of the subsystems of the distributed control system in HT-7 tokamak (HT7DCS). The main function of the subsystem is to control the plasma density on real-time. For this reason, the real-time capability and good stability are the most significant factors, which will influence the control results. Since the former plasma density feedback control system (FPDFCS) based on Windows operation system could not fulfill such requirements well, a new subsystem has to be developed. The paper describes the upgrade of the plasma density feedback control system (UPDFCS), based on the dual operation system (Windows and Linux), in detail.

  12. Modelling of the ICRF induced E  ×  B convection in the scrape-off-layer of ASDEX Upgrade

    Science.gov (United States)

    Zhang, W.; Feng, Y.; Noterdaeme, J.-M.; Bobkov, V.; Colas, L.; Coster, D.; Lunt, T.; Bilato, R.; Jacquot, J.; Ochoukov, R.; Van Eester, D.; Křivská, A.; Jacquet, P.; Guimarais, L.; the ASDEX Upgrade Team

    2016-09-01

    In magnetic controlled fusion devices, plasma heating with radio-frequency (RF) waves in the ion cyclotron (IC) range of frequency relies on the electric field of the fast wave to heat the plasma. However, the slow wave can be generated parasitically. The electric field of the slow wave can induce large biased plasma potential (DC potential) through sheath rectification. The rapid variation of the rectified potential across the equilibrium magnetic field can cause significant convective transport (E  ×  B drifts) in the scrape-off layer (SOL). In order to understand this phenomenon and reproduce the experiments, 3D realistic simulations are carried out with the 3D edge plasma fluid and kinetic neutral code EMC3-Eirene in ASDEX Upgrade. For this, we have added the prescribed drift terms to the EMC3 equations and verified the 3D code results against the analytical ones in cylindrical geometry. The edge plasma potential derived from the experiments is used to calculate the drift velocities, which are then treated as input fields in the code to obtain the final density distributions. Our simulation results are in good agreement with the experiments.

  13. 2-dimensional mapping of ICRF-induced scrape-off layer modifications with a retarding field analyser on ASDEX-Upgrade

    Science.gov (United States)

    Colas, L.; Bobkov, V.; Carralero, D.; Kočan, M.; Müller, H. W.; Manz, P.; Kubič, M.; Gunn, J. P.; Herrmann, A.; Rohde, V.; ASDEX-Upgrade Team

    2014-02-01

    Using a reciprocating Retarding Field Analyser (RFA), Scrape-Off Layer (SOL) modifications were investigated on ASDEX-Upgrade during heating with waves in the Ion Cyclotron Range of Frequencies (ICRF), suspected for enhanced impurity production in this all-metal machine. Two quantities involved in the sputtering were measured: the current Islit on a saturated slit plate, proportional to the parallel ion flux and the mean parallel energy t of collected ions, averaged over many RF cycles. Combining multiple RFA reciprocations over a scan of q95 provided 2D poloidal/radial resolution. In the outer SOL a localized RF-perturbed zone was evidenced on the RFA side magnetically connected to an active ICRF antenna. A flat 2D Islit pattern surrounded by steep gradients was observed, correlatively with t exceeding 150eV. The centre of the zone is connected radially slightly behind the leading edge of antenna side limiters, with a radial extension up to ±2cm. The zone is broadest and t is largest near the bottom of the active antenna. This is interpreted as a zone of local plasma biasing via sheath rectification, creating density convection around it. The Islit pattern is qualitatively consistent with simple considerations about E×B particle convection.

  14. 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.

  15. 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.

  16. 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 in...

  17. FT Tokamak Upgrade (FTU) vacuum vessel section cleaning by glow discharge in hydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Ciotti, M.; Apicella, M.L.; Verdini, L.; Ferro, C.

    1991-09-01

    The possibility of applying glow discharge in hydrogen for the cleaning of the FTU (Frascati Tokamak Upgrade) vacuum chamber was analyzed on a 1:1 scale toroidal section by using the same operating conditions as foreseen for the machine. The discharge was maintained for six hours in the chamber with the wall temperature kept at 150 degrees C. The partial pressures at the end of the cleaning run were compared with those obtained by using only thermal outgassing at the same temperature. A reduction of about a factor of two in the H/sub 2/0 and C0/sub 2/ partial pressures was observed, related to a better cleanness of the surface. It was found that the high temperature during the glow discharge cleaning not only increases the efficiency of the discharge, but it is an efficient tool to remove impurities from the hidden regions, defined by the thermal shields that cover all the vacuum vessel walls not directly exposed to the glow discharge.

  18. Tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Meglicki, Z

    1995-09-19

    We describe in detail the implementation of a weighted differences code, which is used to simulate a tokamak using the Maschke-Perrin solution as an initial condition. The document covers the mainlines of the program and the most important problem-specific functions used in the initialization, static tests, and dynamic evolution of the system. The mathematics of the Maschke-Perrin solution is discussed in parallel with its realisation within the code. The results of static and dynamic tests are presented in sections discussing their implementation.The code can also be obtained by ftp -anonymous from cisr.anu.edu.au Directory /pub/papers/meglicki/src/tokamak. This code is copyrighted. (author). 13 refs.

  19. Upgrade of Langmuir probe diagnostic in ITER-like tungsten mono-block divertor on experimental advanced superconducting tokamak

    Science.gov (United States)

    Xu, J. C.; Wang, L.; Xu, G. S.; Luo, G. N.; Yao, D. M.; Li, Q.; Cao, L.; Chen, L.; Zhang, W.; Liu, S. C.; Wang, H. Q.; Jia, M. N.; Feng, W.; Deng, G. Z.; Hu, L. Q.; Wan, B. N.; Li, J.; Sun, Y. W.; Guo, H. Y.

    2016-08-01

    In order to withstand rapid increase in particle and power impact onto the divertor and demonstrate the feasibility of the ITER design under long pulse operation, the upper divertor of the EAST tokamak has been upgraded to actively water-cooled, ITER-like tungsten mono-block structure since the 2014 campaign, which is the first attempt for ITER on the tokamak devices. Therefore, a new divertor Langmuir probe diagnostic system (DivLP) was designed and successfully upgraded on the tungsten divertor to obtain the plasma parameters in the divertor region such as electron temperature, electron density, particle and heat fluxes. More specifically, two identical triple probe arrays have been installed at two ports of different toroidal positions (112.5-deg separated toroidally), which can provide fundamental data to study the toroidal asymmetry of divertor power deposition and related 3-dimension (3D) physics, as induced by resonant magnetic perturbations, lower hybrid wave, and so on. The shape of graphite tip and fixed structure of the probe are designed according to the structure of the upper tungsten divertor. The ceramic support, small graphite tip, and proper connector installed make it possible to be successfully installed in the very narrow interval between the cassette body and tungsten mono-block, i.e., 13.5 mm. It was demonstrated during the 2014 and 2015 commissioning campaigns that the newly upgraded divertor Langmuir probe diagnostic system is successful. Representative experimental data are given and discussed for the DivLP measurements, then proving its availability and reliability.

  20. On the measurement of the threshold electric field for runaway electron generation in the Frascati Tokamak Upgrade

    Science.gov (United States)

    Popovic, Z.; Esposito, B.; Martín-Solís, J. R.; Bin, W.; Buratti, P.; Carnevale, D.; Causa, F.; Gospodarczyk, M.; Marocco, D.; Ramogida, G.; Riva, M.

    2016-12-01

    Experiments have been carried out to evaluate the threshold electric field for runaway generation during the flat-top phase of ohmic discharges in the Frascati Tokamak Upgrade tokamak. An investigation of the conditions for runaway electron generation and suppression has been performed for a wide range of plasma parameter values. The measured threshold electric field is found to be significantly larger ( ˜2 -5 times) than predicted by the relativistic collissional theory of runaway generation, ER=ne e3 lnΛ/4 π ɛ02 me c2 , and can be explained to a great extent by an increase of the critical electric field due to the effect of the electron synchrotron radiation losses. These findings are consistent with the results of an ITPA joint experiment to study the onset, growth, and decay of relativistic runaway electrons [Granetz et al., Phys. Plasmas 21, 072506 (2014)]. Confirmation of these results for disruptions with high electric field might imply significantly lower requirements on electron densities for suppression and prevention of runaway formation in ITER.

  1. 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...

  2. 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...

  3. Applications of ECH on the DIII-D tokamak and projections for future ECH upgrades

    Directory of Open Access Journals (Sweden)

    Solomon W.M.

    2012-09-01

    Full Text Available Electron Cyclotron Heating and Current Drive plays an important role in the DIII-D program. In high performance discharges EC power contributes greatly to MHD stability, and this is particularly important for discharges with low rotational torque applied, as will be the case for ITER. Off-axis EC current drive also plays a key role in the actualization of steady-state scenarios by supporting the desired current profile. In order to carry out these applications at higher beta and higher field, an upgrade of the EC power to 15 MW is needed, and the best gyrotron frequency for the DIII-D program is 117.5 GHz.

  4. First studies of ITER-diagnostic mirrors in a tokamak with an all-metal interior: results of the first mirror test in ASDEX Upgrade

    NARCIS (Netherlands)

    Litnovsky, A.; Matveeva, M.; Herrmann, A.; Rohde, V.; Mayer, M.; Sugiyama, K.; Krieger, K.; Voitsenya, V.; Vayakis, G.; Costley, A. E.; Reichle, R.; De Temmerman, G.; Richter, S.; Breuer, U.; Buzi, L.; Möller, S.; Philipps, V.; Samm, U.; Wienhold, P.

    2013-01-01

    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 associated diagnostics. The most adverse effect on mirror performance is caused by the deposition of impurities. It is e

  5. GPEC, a real-time capable Tokamak equilibrium code

    CERN Document Server

    Rampp, Markus; Fischer, Rainer

    2015-01-01

    A new parallel equilibrium reconstruction code for tokamak plasmas is presented. GPEC allows to compute equilibrium flux distributions sufficiently accurate to derive parameters for plasma control within 1 ms of runtime which enables real-time applications at the ASDEX Upgrade experiment (AUG) and other machines with a control cycle of at least this size. The underlying algorithms are based on the well-established offline-analysis code CLISTE, following the classical concept of iteratively solving the Grad-Shafranov equation and feeding in diagnostic signals from the experiment. The new code adopts a hybrid parallelization scheme for computing the equilibrium flux distribution and extends the fast, shared-memory-parallel Poisson solver which we have described previously by a distributed computation of the individual Poisson problems corresponding to different basis functions. The code is based entirely on open-source software components and runs on standard server hardware and software environments. The real-...

  6. Electron cyclotron emission radiometer upgrade on the J-TEXT tokamak

    Science.gov (United States)

    Yang, Z. J.; Pan, X. M.; Ma, X. D.; Ruan, B. W.; Zhou, R. B.; Zhang, C.

    2016-11-01

    To meet experimental requirements, the J-TEXT electron cyclotron emission (ECE) diagnostic is being upgraded. The front end antenna and transmission line have been modified and a new 8-channel W-band detecting unit has been developed. The improved ECE system will extend the frequency range from 94.5-124.5 GHz to 80.5-124.5 GHz. This will enable the system to cover the most plasma in the radius direction for BT = 1.8-2.2 T, and it even can cover almost the whole plasma range ρ = - 0.8-0.9 (minus means the high field side) at BT = 1.8 T. A new auxiliary channel bank with 8 narrow band, tunable yttrium iron garnet filters is planned to add to the ECE system. Due to observations along a major radius, perpendicular to BT, and relatively low electron temperature, Doppler and relativistic broadening are minimal and thus high spatial resolution measurements can be made at variable locations with these tunable channels.

  7. 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...

  8. 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 ...

  9. 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 ...

  10. 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 ...

  11. UPGRADES

    CERN Multimedia

    D. Contardo and J. Spalding

    2013-01-01

      LS1 and Phase 1 The detector projects targeting LS1 are progressing well, and a fully integrated schedule developed by Technical Coordination includes installation milestones and a detailed work-plan. The first chambers of the RPC system were produced and are being qualified. Production will ramp up this year to a rate of 20 chambers per month. 32 chambers of the CSC system have been fabricated for the ME4/2 CSC stations, and production proceeds at a rate of 4 per month. The new ME1/1 Front-End Board is in production and the off-detector electronics integration tests are ongoing. The new Theta Trigger Boards for the DT readout production is started and the relocation of the Sector Collector boards with new Optical Links as been successfully tested. All the components for the upgrade of the Forward Hadron Calorimeter PMTs have been received at CERN and assemblies are being qualified. The situation is similar for the Hadron Outer Calorimeter new SiPMs and readout modules. Three projects are plan...

  12. Recent advances in gyrokinetic full-f particle simulation of medium sized Tokamaks with ELMFIRE

    Energy Technology Data Exchange (ETDEWEB)

    Janhunen, S.J.; Kiviniemi, T.P.; Korpio, T.; Leerink, S.; Nora, M. [Helsinki University of Technology, Euratom-Tekes Association, Espoo (Finland); Heikkinen, J.A. [VTT, Euratom-Tekes Association, Espoo (Finland); Ogando, F. [Helsinki University of Technology, Euratom-Tekes Association, Espoo (Finland); Universidad Nacional de Educacion a Distancia, Madrid (Spain)

    2010-05-15

    Large-scale kinetic simulations of toroidal plasmas based on first principles are called for in studies of transition from low to high confinement mode and internal transport barrier formation in the core plasma. Such processes are best observed and diagnosed in detached plasma conditions in mid-sized tokamaks, so gyrokinetic simulations for these conditions are warranted. A first principles test-particle based kinetic model ELMFIRE[1] has been developed and used in interpretation[1,2] of FT-2 and DIII-D experiments. In this work we summarize progress in Cyclone (DIII-D core) and ASDEX Upgrade pedestal region simulations, and show that in simulations the choice of adiabatic electrons results in quenching of turbulence (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  13. Analysis of fast ion induced instabilities in tokamak plasmas

    CERN Document Server

    Horváth, László

    2015-01-01

    In magnetic confinement fusion devices like tokamaks, it is crucial to confine the high energy fusion-born helium nuclei ($\\alpha$-particles) to maintain the energy equilibrium of the plasma. However, energetic ions can excite various instabilities which can lead to their enhanced radial transport. Consequently, these instabilities may degrade the heating efficiency and they can also cause harmful power loads on the plasma-facing components of the device. Therefore, the understanding of these modes is a key issue regarding future burning plasma experiments. One of the main open questions concerning energetic particle (EP) driven instabilities is the non-linear evolution of the mode structure. In this thesis, I present my results on the investigation of $\\beta$-induced Alfv\\'{e}n eigenmodes (BAEs) and EP-driven geodesic acoustic modes (EGAMs) observed in the ramp-up phase of off-axis NBI heated plasmas in the ASDEX Upgrade tokamak. These modes were well visible on several line-of-sights (LOSs) of the soft X-ra...

  14. Sawtooth mitigation in 3D MHD tokamak modelling with applied magnetic perturbations

    Science.gov (United States)

    Bonfiglio, D.; Veranda, M.; Cappello, S.; Chacón, L.; Escande, D. F.

    2017-01-01

    The effect of magnetic perturbations (MPs) on the sawtoothing dynamics of the internal kink mode in the tokamak is discussed in the framework of nonlinear 3D MHD modelling. Numerical simulations are performed with the pixie3d code (Chacón 2008 Phys. Plasmas 15 056103) based on a D-shaped configuration in toroidal geometry. MPs are applied as produced by two sets of coils distributed along the toroidal direction, one set located above and the other set below the outboard midplane, like in experimental devices such as DIII-D and ASDEX Upgrade. The capability of n  =  1 MPs to affect quasi-periodic sawteeth is shown to depend on the toroidal phase difference Δ φ between the perturbations produced by the two sets of coils. In particular, sawtooth mitigation is obtained for the Δ φ =π phasing, whereas no significant effect is observed for Δ φ =0 . Numerical findings are explained by the interplay between different poloidal harmonics in the spectrum of applied MPs, and appear to be consistent with experiments performed in the DIII-D device. Sawtooth mitigation and stimulation of self-organized helical states by applied MPs have been previously demonstrated in both circular tokamak and reversed-field pinch (RFP) experiments in the RFX-mod device, and in related 3D MHD modelling.

  15. Bulk ion heating with ICRF waves in tokamaks

    Energy Technology Data Exchange (ETDEWEB)

    Mantsinen, M. J., E-mail: mervi.mantsinen@bsc.es [Catalan Institution for Research and Advanced Studies, Barcelona (Spain); Barcelona Supercomputing Center, Barcelona (Spain); Bilato, R.; Bobkov, V. V.; Kappatou, A.; McDermott, R. M.; Odstrčil, T.; Tardini, G.; Bernert, M.; Dux, R.; Maraschek, M.; Noterdaeme, J.-M.; Ryter, F.; Stober, J. [Max-Planck-Institut für Plasmaphysik, Garching (Germany); Nocente, M. [Dipartimento di Fisica “G. Occhialini”, Università degli Studi di Milano-Bicocca, Milano (Italy); Istituto di Fisica del Plasma “P. Caldirola”, CNR, Milano (Italy); Hellsten, T. [Dept. of Fusion Plasma Physics, EES, KTH, Stockholm (Sweden); Mantica, P.; Tardocchi, M. [Istituto di Fisica del Plasma “P. Caldirola”, CNR, Milano (Italy); Nielsen, S. K.; Rasmussen, J.; Stejner, M. [Technical University of Denmark, Department of Physics, Lyngby (Denmark); and others

    2015-12-10

    Heating with ICRF waves is a well-established method on present-day tokamaks and one of the heating systems foreseen for ITER. However, further work is still needed to test and optimize its performance in fusion devices with metallic high-Z plasma facing components (PFCs) in preparation of ITER and DEMO operation. This is of particular importance for the bulk ion heating capabilities of ICRF waves. Efficient bulk ion heating with the standard ITER ICRF scheme, i.e. the second harmonic heating of tritium with or without {sup 3}He minority, was demonstrated in experiments carried out in deuterium-tritium plasmas on JET and TFTR and is confirmed by ICRF modelling. This paper focuses on recent experiments with {sup 3}He minority heating for bulk ion heating on the ASDEX Upgrade (AUG) tokamak with ITER-relevant all-tungsten PFCs. An increase of 80% in the central ion temperature T{sub i} from 3 to 5.5 keV was achieved when 3 MW of ICRF power tuned to the central {sup 3}He ion cyclotron resonance was added to 4.5 MW of deuterium NBI. The radial gradient of the T{sub i} profile reached locally values up to about 50 keV/m and the normalized logarithmic ion temperature gradients R/LT{sub i} of about 20, which are unusually large for AUG plasmas. The large changes in the T{sub i} profiles were accompanied by significant changes in measured plasma toroidal rotation, plasma impurity profiles and MHD activity, which indicate concomitant changes in plasma properties with the application of ICRF waves. When the {sup 3}He concentration was increased above the optimum range for bulk ion heating, a weaker peaking of the ion temperature profile was observed, in line with theoretical expectations.

  16. Texas Experimental Tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Wootton, A.J.

    1993-04-01

    This progress report covers the period from November 1, 1990 to April 30, 1993. During that period, TEXT was operated as a circular tokamak with a material limiter. It was devoted to the study of basic plasma physics, in particular to study of fluctuations, turbulence, and transport. The purpose is to operate and maintain TEXT Upgrade as a complete facility for applied tokamak physics, specifically to conduct a research program under the following main headings: (1) to elucidate the mechanisms of working gas, impurity, and thermal transport in tokamaks, in particular to understand the role of turbulence; (2) to study physics of the edge plasma, in particular the turbulence; (3) to study the physics or resonant magnetic fields (ergodic magnetic divertors, intra island pumping); and (4) to study the physics of electron cyclotron heating (ECRH). Results of studies in each of these areas are reported.

  17. High speed cine film studies of plasma behaviour and plasma surface interactions in tokamaks

    Energy Technology Data Exchange (ETDEWEB)

    Goodall, D.H.J. (Euratom/UKAEA Fusion Association, Abingdon (UK). Culham Lab.)

    High speed cine photography is a useful diagnostic aid for studying plasma behaviour and plasma surface interactions. Several workers have filmed discharges in tokamaks including ASDEX, DITE, DIVA, ISX, JFT2, TFR and PLT. These films are discussed and examples given of the observed phenomena which include plasma limiter interactions, diverted discharges, disruptions, magnetic islands and moving glowing objects often known as 'UFOs'. Examples of plasma structures in ASDEX and DITE not previously published are also given. The paper also reports experiments in DITE to determine the origin of UFOs.

  18. Investigation of power spreading in a tokamak divertor using numerical tools

    Energy Technology Data Exchange (ETDEWEB)

    Hoppe, Felix; Scarabosio, Andrea; Wischmeier, Marco [Max-Planck Institut fuer Plasmaphysik, Boltzmannstr. 2, 85748 Garching (Germany); Collaboration: ASDEX Upgrade Team

    2013-07-01

    Divertors are widely used in today's fusion devices in order to reduce plasma core impurities and improve energy confinement. As the divertor targets are exposed to the largest part of the particle and heat loads reaching the wall, these loads must be reduced to prevent material damage. An enhancement of the plasma-wetted area on the targets is one approach. In low density plasmas, the plasma-wetted area is mainly given by the width of the scrap-off-layer (SOL) plasma at the divertor entrance, modified by heat diffusion into the private flux region (PFR) in the divertor. The heat diffusion broadens the heat flux profile at the targets. This can be approximated by a convolution of the upstream profile with a Gaussian of width S. The SOLPS5.0 code package is used to study the influence of divertor geometry and neutral pressure on S. The code is then validated by comparing the numerical results to the experimental findings in the ASDEX Upgrade tokamak.

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

    DEFF Research Database (Denmark)

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

    2015-01-01

    to be the decisive element for the L–H power threshold. A physics based scaling of the density at which the minimum PLH occurs indicates that ITER could take advantage of it to initiate H-mode at lower density than that of the final Q = 10 operational point. Core density fluctuation measurements resolved in radius...

  20. Global performance enhancements via pedestal optimisation on ASDEX Upgrade

    Science.gov (United States)

    Dunne, M. G.; Frassinetti, L.; Beurskens, M. N. A.; Cavedon, M.; Fietz, S.; Fischer, R.; Giannone, L.; Huijsmans, G. T. A.; Kurzan, B.; Laggner, F.; McCarthy, P. J.; McDermott, R. M.; Tardini, G.; Viezzer, E.; Willensdorfer, M.; Wolfrum, E.; The EUROfusion MST1 Team; The ASDEX Upgrade Team

    2017-02-01

    Results of experimental scans of heating power, plasma shape, and nitrogen content are presented, with a focus on global performance and pedestal alteration. In detailed scans at low triangularity, it is shown that the increase in stored energy due to nitrogen seeding stems from the pedestal. It is also shown that the confinement increase is driven through the temperature pedestal at the three heating power levels studied. In a triangularity scan, an orthogonal effect of shaping and seeding is observed, where increased plasma triangularity increases the pedestal density, while impurity seeding (carbon and nitrogen) increases the pedestal temperature in addition to this effect. Modelling of these effects was also undertaken, with interpretive and predictive models being employed. The interpretive analysis shows a general agreement of the experimental pedestals in separate power, shaping, and seeding scans with peeling-ballooning theory. Predictive analysis was used to isolate the individual effects, showing that the trends of additional heating power and increased triangularity can be recoverd. However, a simple change of the effective charge in the plasma cannot explain the observed levels of confinement improvement in the present models.

  1. Fast particle-driven ion cyclotron emission (ICE) in tokamak plasmas and the case for an ICE diagnostic in ITER

    CERN Document Server

    McClements, K G; Dendy, R O; Carbajal, L; Chapman, S C; Cook, J W S; Harvey, R W; Heidbrink, W W; Pinches, S D

    2014-01-01

    Fast particle-driven waves in the ion cyclotron frequency range (ion cyclotron emission or ICE) have provided a valuable diagnostic of confined and escaping fast ions in many tokamaks. This is a passive, non-invasive diagnostic that would be compatible with the high radiation environment of deuterium-tritium plasmas in ITER, and could provide important information on fusion {\\alpha}-particles and beam ions in that device. In JET, ICE from confined fusion products scaled linearly with fusion reaction rate over six orders of magnitude and provided evidence that {\\alpha}-particle confinement was close to classical. In TFTR, ICE was observed from super-Alfv\\'enic {\\alpha}-particles in the plasma edge. The intensity of beam-driven ICE in DIII-D is more strongly correlated with drops in neutron rate during fishbone excitation than signals from more direct beam ion loss diagnostics. In ASDEX Upgrade ICE is produced by both super-Alfv\\'enic DD fusion products and sub-Alfv\\'enic deuterium beam ions.

  2. Gyrokinetic study of turbulent convection of heavy impurities in tokamak plasmas at comparable ion and electron heat fluxes

    Science.gov (United States)

    Angioni, C.; Bilato, R.; Casson, F. J.; Fable, E.; Mantica, P.; Odstrcil, T.; Valisa, M.; ASDEX Upgrade Team; Contributors, JET

    2017-02-01

    In tokamaks, the role of turbulent transport of heavy impurities, relative to that of neoclassical transport, increases with increasing size of the plasma, as clarified by means of general scalings, which use the ITER standard scenario parameters as reference, and by actual results from a selection of discharges from ASDEX Upgrade and JET. This motivates the theoretical investigation of the properties of the turbulent convection of heavy impurities by nonlinear gyrokinetic simulations in the experimentally relevant conditions of comparable ion and electron heat fluxes. These conditions also correspond to an intermediate regime between dominant ion temperature gradient turbulence and trapped electron mode turbulence. At moderate plasma toroidal rotation, the turbulent convection of heavy impurities, computed with nonlinear gyrokinetic simulations, is found to be directed outward, in contrast to that obtained by quasi-linear calculations based on the most unstable linear mode, which is directed inward. In this mixed turbulence regime, with comparable electron and ion heat fluxes, the nonlinear results of the impurity transport can be explained by the coexistence of both ion temperature gradient and trapped electron modes in the turbulent state, both contributing to the turbulent convection and diffusion of the impurity. The impact of toroidal rotation on the turbulent convection is also clarified.

  3. Characterization and scaling of the tokamak edge transport barrier

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, Philip Adrian

    2012-04-24

    The high confinement regime (H-mode) in a tokamak plasma displays a remarkable edge region. On a small spatial scale of 1-2 cm the properties of the plasma change significantly. Certain parameters vary 1-2 orders of magnitude in this region, called the pedestal. Currently, there is no complete understanding of how the pedestal forms or how it is sustained. The goal of this thesis is to contribute to the theoretical understanding of the pedestal and provide scalings towards larger machines, like ITER and DEMO. A pedestal database was built with data from different tokamaks: ASDEX Upgrade, DIIID and JET. The pedestal was characterized with the same method for all three machines. This gives the maximum value, gradient and width of the pedestal in n{sub e}, T{sub e} and T{sub i}. These quantities were analysed along with quantities derived from them, such as the pressure or the confinement time. For this purpose two parameter sets were used: normalized parameters (pressure {beta}, time {nu}{sub *}, length {rho}{sub *}, shape f{sub q}) and machine parameters (size a, magnetic field B{sub t}, plasma current I{sub p}, heating P). All results are dependent on the choice of the coordinate system: normalized poloidal flux {Psi}{sub N} and real space r/a. The most significant result, which was obtained with both parameter sets, shows a different scaling of the pedestal width for the electron temperature and the electron density. The presented scalings predict that in ITER and DEMO the temperature pedestal will be appreciably wider than the density pedestal. The pedestal top scaling for the pressure reveals differences between the electron and the ion pressure. In extrapolations this results in values for T{sub e,ped} of 4 keV (ITER) and 10 keV (DEMO), but significantly lower values for the ion temperature. A two-term method was applied to use the pedestal pressure to determine the pedestal contribution to the global confinement time {tau}{sub E}. The dependencies in the

  4. Status of tokamak research

    Energy Technology Data Exchange (ETDEWEB)

    Rawls, J.M. (ed.)

    1979-10-01

    An overall review of the tokamak program is given with particular emphasis upon developments over the past five years in the theoretical and experimental elements of the program. A summary of the key operating parameters for the principal tokamaks throughout the world is given. Also discussed are key issues in plasma confinement, plasma heating, and tokamak design. (MOW)

  5. 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...

  6. 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.

  7. 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.

  8. ECE Imaging Bandwidth Upgrade for TEXTOR

    Science.gov (United States)

    Domier, C. W.; Zhang, P.; Luhmann, N. C., Jr.; Park, H. K.; van de Pol, M. J.; Spakman, G. W.; Jaspers, R.; Donne, A. J. H.

    2007-11-01

    The 128 channel 2-D Electron Cyclotron Emission (ECE) Imaging system collects time-resolved 16x8 images of electron temperature profiles and fluctuations on the TEXTOR tokamak. This instrument was upgraded in February 2007 with new wideband ECE electronics which increased the instantaneous frequency coverage by >50% to 6.4 GHz with a corresponding increase in horizontal plasma coverage. Frequency extenders have been developed to combine modules together to double the instantaneous coverage to 12.8 GHz. Technical details regarding both the electronics upgrade and the frequency extenders as well as the preliminary physics results will be presented. Implementation of a similar but new ECEI instrument on the DIII-D tokamak will be extensively discussed.

  9. Tokamak engineering mechanics

    CERN Document Server

    Song, Yuntao; Du, Shijun

    2013-01-01

    Tokamak Engineering Mechanics offers concise and thorough coverage of engineering mechanics theory and application for tokamaks, and the material is reinforced by numerous examples. Chapter topics include general principles, static mechanics, dynamic mechanics, thermal fluid mechanics and multiphysics structural mechanics of tokamak structure analysis. The theoretical principle of the design and the methods of the analysis for various components and load conditions are presented, while the latest engineering technologies are also introduced. The book will provide readers involved in the study

  10. Scoping study for compact high-field superconducting net energy tokamaks

    Science.gov (United States)

    Mumgaard, R. T.; Greenwald, M.; Freidberg, J. P.; Wolfe, S. M.; Hartwig, Z. S.; Brunner, D.; Sorbom, B. N.; Whyte, D. G.

    2016-10-01

    The continued development and commercialization of high temperature superconductors (HTS) may enable the construction of compact, net-energy tokamaks. HTS, in contrast to present generation low temperature superconductors, offers improved performance in high magnetic fields, higher current density, stronger materials, higher temperature operation, and simplified assembly. Using HTS along with community-consensus confinement physics (H98 =1) may make it possible to achieve net-energy (Q>1) or burning plasma conditions (Q>5) in DIII-D or ASDEX-U sized, conventional aspect ratio tokamaks. It is shown that, by operating at high plasma current and density enabled by the high magnetic field (B>10T), the required triple products may be achieved at plasma volumes under 20m3, major radii under 2m, with external heating powers under 40MW. This is at the scale of existing devices operated by laboratories, universities and companies. The trade-offs in the core heating, divertor heat exhaust, sustainment, stability, and proximity to known plasma physics limits are discussed in the context of the present tokamak experience base and the requirements for future devices. The resulting HTS-based design space is compared and contrasted to previous studies on high-field copper experiments with similar missions. The physics exploration conducted with such HTS devices could decrease the real and perceived risks of ITER exploitation, and aid in quickly developing commercially-applicable tokamak pilot plants and reactors.

  11. 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...... the fast-ion distribution function in 2D velocity space....

  12. 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

    during on-axis injection and outwards shifted profiles during off-axis injection. Due to this change of the fast-ion population, a clear modification of the plasma current profile is predicted but not observed by a motional Stark effect diagnostic. The fast-ion transport caused by MHD activity has been...... studied in low collisionality discharges that exhibit strong (1, 1) modes. In particular due to sawtooth crashes, significant radial redistribution of co-rotating fast-ions is observed which can very well be described by the Kadomtsev model. In addition, first tomographic reconstructions of the central 2D...

  13. 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

    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....

  14. Arc erosion of full metal plasma facing components at the inner baffle region of ASDEX Upgrade

    Directory of Open Access Journals (Sweden)

    V. Rohde

    2016-12-01

    Full Text Available At the inner baffle of the AUG divertor massive polished inserts of tungsten and P92 steel were installed to measure the erosion by arcing. For tungsten most of the traces are less than 0.4µm deep and a similar amount of tungsten is deposited close to the traces. Few craters up to 4µm resulting in an average erosion rate of 2×1013 at cm−2s−1 are observed. The behaviour for P92 steel is quite different: most of the traces are 4µm deep, up to 80µm were observed. An average erosion rate of 400×1013 at cm−2s−1, i.e. more than a factor of hundred higher compared to tungsten, is found. Therefore, erosion by arcing has to be taken into account to determine the optimal material mix for future fusion devices.

  15. 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;

    2014-01-01

    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...

  16. 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...

  17. 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 device...

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

    DEFF Research Database (Denmark)

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

    2008-01-01

    GHz) to resolve the one-dimensional velocity distribution of the confined fast ions. The steerable antennas will allow different scattering geometries to fully explore the anisotropic fast ion distributions at different spatial locations. This paper covers the capabilities and operational limits...

  19. Trends of W behavior in ICRF assisted discharges in ASDEX Upgrade

    Science.gov (United States)

    Czarnecka, A.; Bobkov, V.; Dux, R.; Pütterich, T.; Sertoli, M.

    2015-08-01

    During Ion Cyclotron Range of Frequencies (ICRF) operation with metallic plasma facing components, plasma wall interaction processes are modified, which needs to be understood in order to reduce the ICRF-related rise in impurity concentration and maximize ICRF coupling. This contribution is focused on gathering and analyzing a database on W-behavior during ICRF spanning a multi-parameter space. The gas puff dependence is investigated in selected pulses that feature the injection of deuterium (D2) main gas, with impurity gas nitrogen (N2), argon (Ar) and krypton (Kr). CW was found to decrease with the total gas injection rate, which was also correlated with the changes of electron density in the location of the CW measurements. Although the addition of N2, Ar and Kr impacted on the increase in sputtering, to achieve a similar CW level with mixed puffing, one needs to inject considerably more gas. Moreover, CW is shown to change after implementation of boron coatings on the ICRF antenna limiters.

  20. 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.

  1. 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

    . The paper discusses a comparable simple extension of the model by introducing a non-zero characteristic velocity of the Maxwellian distributed particles. This way the experimentally observed temporal evolution as well as the in/out energy imbalance can be described. The extended model named free......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...

  2. ATLAS UPGRADES

    CERN Document Server

    Lacasta, C; The ATLAS collaboration

    2014-01-01

    After the successful LHC operation at the center-of-mass energies of 7 and 8 TeV in 2010 - 2012, 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 final 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. Current planning in ATLAS envisions significant upgrades to the detector during the consolidation of the LHC to reach full LHC energy and further upgrades. The challenge of coping with the HL-LHC instantaneous and integrated luminosity, along with the associated radiation levels, requires further major changes to the ATLAS detector. The designs are developing rapidly for ...

  3. Texas Experimental Tokamak. Technical progress report, April 1990--April 1993

    Energy Technology Data Exchange (ETDEWEB)

    Wootton, A.J.

    1993-04-01

    This progress report covers the period from November 1, 1990 to April 30, 1993. During that period, TEXT was operated as a circular tokamak with a material limiter. It was devoted to the study of basic plasma physics, in particular to study of fluctuations, turbulence, and transport. The purpose is to operate and maintain TEXT Upgrade as a complete facility for applied tokamak physics, specifically to conduct a research program under the following main headings: (1) to elucidate the mechanisms of working gas, impurity, and thermal transport in tokamaks, in particular to understand the role of turbulence; (2) to study physics of the edge plasma, in particular the turbulence; (3) to study the physics or resonant magnetic fields (ergodic magnetic divertors, intra island pumping); and (4) to study the physics of electron cyclotron heating (ECRH). Results of studies in each of these areas are reported.

  4. Advanced tokamak concepts

    NARCIS (Netherlands)

    Oomens, A. A. M.

    1998-01-01

    From a discussion of fusion reactor designs based on today's well-established experience gained in the operation of large tokamaks, it is concluded that such reactors are economically not attractive. The physics involved in the various options for concept improvement is described and the main e

  5. Advanced tokamak concepts

    NARCIS (Netherlands)

    Oomens, A. A. M.

    1996-01-01

    From a discussion of fusion reactor designs based on today's well-established experience gained in the operation of large tokamaks, it is concluded that such reactors are economically not attractive. The physics involved in the various options for concept improvement is described and the main e

  6. Transport in gyrokinetic tokamaks

    Energy Technology Data Exchange (ETDEWEB)

    Mynick, H.E.; Parker, S.E.

    1995-01-01

    A comprehensive study of transport in full-volume gyrokinetic (gk) simulations of ion temperature gradient driven turbulence in core tokamak plasmas is presented. Though this ``gyrokinetic tokamak`` is much simpler than experimental tokamaks, such simplicity is an asset, because a dependable nonlinear transport theory for such systems should be more attainable. Toward this end, we pursue two related lines of inquiry. (1) We study the scalings of gk tokamaks with respect to important system parameters. In contrast to real machines, the scalings of larger gk systems (a/{rho}{sub s} {approx_gt} 64) with minor radius, with current, and with a/{rho}{sub s} are roughly consistent with the approximate theoretical expectations for electrostatic turbulent transport which exist as yet. Smaller systems manifest quite different scalings, which aids in interpreting differing mass-scaling results in other work. (2) With the goal of developing a first-principles theory of gk transport, we use the gk data to infer the underlying transport physics. The data indicate that, of the many modes k present in the simulation, only a modest number (N{sub k} {approximately} 10) of k dominate the transport, and for each, only a handful (N{sub p} {approximately} 5) of couplings to other modes p appear to be significant, implying that the essential transport physics may be described by a far simpler system than would have been expected on the basis of earlier nonlinear theory alone. Part of this analysis is the inference of the coupling coefficients M{sub kpq} governing the nonlinear mode interactions, whose measurement from tokamak simulation data is presented here for the first time.

  7. Time-resolved spectroscopy in the Rijnhuizen Tokamak Project tokamak

    NARCIS (Netherlands)

    Box, F. M. A.; Howard, J.; VandeKolk, E.; Meijer, F. G.

    1997-01-01

    At the Rijnhuizen Tokamak Project tokamak spectrometers are used to diagnose the velocity distribution and abundances of impurity ions. Quantities can be measured as a function of time, and the temporal resolution depends on the line emissivity and can be as good as 0.2 ms for the strongest lines. S

  8. Overview of physics results from MAST towards ITER/DEMO and the MAST Upgrade

    NARCIS (Netherlands)

    Meyer, H.; Abel, I. G.; Akers, R. J.; Allan, A.; Allan, S. Y.; Appel, L. C.; Asunta, O.; Barnes, M.; Barratt, N. C.; N. Ben Ayed,; Bradley, J. W.; Canik, J.; Cahyna, P.; Cecconello, M.; Challis, C. D.; Chapman, I.T.; Ciric, D.; Colyer, G.; Conway, N. J.; Cox, M.; Crowley, B. J.; Cowley, S. C.; Cunningham, G.; Danilov, A.; Darke, A.; de Bock, M. F. M.; De Temmerman, G.; Dendy, R. O.; Denner, P.; Dickinson, D.; Dnestrovskij, A. Y.; Dnestrovsky, Y.; Driscoll, M. D.; Dudson, B.; Dunai, D.; Dunstan, M.; Dura, P.; Elmore, S.; Field, A. R.; Fishpool, G.; Freethy, S.; Fundamenski, W.; Garzotti, L.; Ghim, Y. C.; Gibson, K. J.; Gryaznevich, M. P.; Harrison, J.; E. Havlíčková,; Hawkes, N. C.; Heidbrink, W. W.; Hender, T. C.; Highcock, E.; Higgins, D.; Hill, P.; Hnat, B.; Hole, M. J.; J. Horáček,; Howell, D. F.; Imada, K.; Jones, O.; Kaveeva, E.; Keeling, D.; Kirk, A.; M. Kočan,; Lake, R. J.; Lehnen, M.; Leggate, H. J.; Liang, Y.; Lilley, M. K.; Lisgo, S. W.; Liu, Y. Q.; Lloyd, B.; Maddison, G. P.; Mailloux, J.; Martin, R.; McArdle, G. J.; McClements, K. G.; McMillan, B.; Michael, C.; Militello, F.; Molchanov, P.; Mordijck, S.; Morgan, T.; Morris, A. W.; Muir, D. G.; Nardon, E.; Naulin, V.; Naylor, G.; Nielsen, A. H.; O' Brien, M. R.; O' Gorman, T.; Pamela, S.; Parra, F. I.; Patel, A.; Pinches, S. D.; Price, M. N.; Roach, C. M.; Robinson, J. R.; Romanelli, M.; Rozhansky, V.; Saarelma, S.; Sangaroon, S.; Saveliev, A.; Scannell, R.; Seidl, J.; Sharapov, S. E.; Schekochihin, A. A.; Shevchenko, V.; Shibaev, S.; Stork, D.; Storrs, J.; Sykes, A.; Tallents, G. J.; Tamain, P.; Taylor, D.; Temple, D.; Thomas-Davies, N.; Thornton, A.; Turnyanskiy, M. R.; M. Valovič,; Vann, R. G. L.; Verwichte, E.; Voskoboynikov, P.; Voss, G.; Warder, S. E. V.; Wilson, H. R.; Wodniak, I.; Zoletnik, S.; Zagorski, R.; MAST Team,; NBI Team,

    2013-01-01

    New diagnostic, modelling and plant capability on the Mega Ampère Spherical Tokamak (MAST) have delivered important results in key areas for ITER/DEMO and the upcoming MAST Upgrade, a step towards future ST devices on the path to fusion currently under procurement. Micro-stability analysis of the pe

  9. Overview of physics results from MAST towards ITER/DEMO and the MAST Upgrade

    DEFF Research Database (Denmark)

    Meyer, H.; Abel, I.G.; Akers, R.J.

    2013-01-01

    New diagnostic, modelling and plant capability on the Mega Ampère Spherical Tokamak (MAST) have delivered important results in key areas for ITER/DEMO and the upcoming MAST Upgrade, a step towards future ST devices on the path to fusion currently under procurement. Micro-stability analysis of the...

  10. Magnetic confinement experiment -- 1: Tokamaks

    Energy Technology Data Exchange (ETDEWEB)

    Goldston, R.J.

    1994-12-31

    This report reviews presentations made at the 15th IAEA Conference on Plasma Physics and Controlled Nuclear Fusion on experimental tokamak physics, particularly on advances in core plasma physics, divertor and edge physics, heating and current drive, and tokamak concept optimization.

  11. LIDAR Thomson scattering for advanced tokamaks. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Molvik, A.W.; Lerche, R.A.; Nilson, D.G. [and others

    1996-03-18

    The LIDAR Thomson Scattering for Advanced Tokamaks project made a valuable contribution by combining LLNL expertise from the MFE Program: tokamak design and diagnostics, and the ICF Program and Physics Dept.: short-pulse lasers and fast streak cameras. This multidisciplinary group evaluated issues involved in achieving a factor of 20 higher high spatial resolution (to as small as 2-3 mm) from the present state of the art in LIDAR Thomson scattering, and developed conceptual designs to apply LIDAR Thomson scattering to three tokamaks: Upgraded divertor measurements in the existing DIII-D tokamak; Both core and divertor LIDAR Thomson scattering in the proposed (now cancelled) TPX; and core, edge, and divertor LIDAR Thomson scattering on the presently planned International Tokamak Experimental Reactor, ITER. Other issues were evaluated in addition to the time response required for a few millimeter spatial resolution. These include the optimum wavelength, 100 Hz operation of the laser and detectors, minimizing stray light - always the Achilles heel of Thomson scattering, and time dispersion in optics that could prevent good spatial resolution. Innovative features of our work included: custom short pulsed laser concepts to meet specific requirements, use of a prism spectrometer to maintain a constant optical path length for high temporal and spatial resolution, the concept of a laser focus outside the plasma to ionize gas and form an external fiducial to use in locating the plasma edge as well as to spread the laser energy over a large enough area of the inner wall to avoid laser ablation of wall material, an improved concept for cleaning windows between shots by means of laser ablation, and the identification of a new physics issue - nonlinear effects near a laser focus which could perturb the plasma density and temperature that are to be measured.

  12. 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

  13. Edge turbulence in tokamaks

    Science.gov (United States)

    Nedospasov, A. V.

    1992-12-01

    Edge turbulence is of decisive importance for the distribution of particle and energy fluxes to the walls of tokamaks. Despite the availability of extensive experimental data on the turbulence properties, its nature still remains a subject for discussion. This paper contains a review of the most recent theoretical and experimental studies in the field, including mainly the studies to which Wootton (A.J. Wooton, J. Nucl. Mater. 176 & 177 (1990) 77) referred to most in his review at PSI-9 and those published later. The available theoretical models of edge turbulence with volume dissipation due to collisions fail to fully interpret the entire combination of experimental facts. In the scrape-off layer of a tokamak the dissipation prevails due to the flow of current through potential shifts near the surface of limiters of divertor plates. The different origins of turbulence at the edge and in the core plasma due to such dissipation are discussed in this paper. Recent data on the electron temperature fluctuations enabled one to evaluate the electric probe measurements of turbulent flows of particles and heat critically. The latest data on the suppression of turbulence in the case of L-H transitions are given. In doing so, the possibility of exciting current instabilities in biasing experiments (rather than only to the suppression of existing turbulence) is given some attention. Possible objectives of further studies are also discussed.

  14. Upgrading uncompetitive products economically

    DEFF Research Database (Denmark)

    Lu, Hua; Jensen, Christian Søndergaard

    2012-01-01

    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...... by the join approach to prune upgrade candidates with uncompetitive upgrade costs. Empirical studies with synthetic and real data show that the join approach is efficient and scalable....

  15. 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.

  16. Microwave Imaging Reflectometer (MIR) Development for the EAST Tokamak

    Science.gov (United States)

    Domier, Calvin; Hu, Xing; Spear, Alexander; Zhu, Yilun; Xie, Jinlin; Luhmann, Neville

    2016-10-01

    An upgraded MIR system is being developed for the EAST tokamak based on the successful DIII-D MIR system. The EAST MIR system has 8 radial channels consisting of 8 independent probing frequencies ranging from 75 to 103 GHz, driven by fast tuning synthesizers and active frequency multipliers. There are 12 poloidal channels in the heterodyne down-conversion receiver system, with each channel corresponding to a separate poloidal position inside the tokamak. The down-conversion electronics are designed to optimize signal to noise ratio and are embedded with a microcontroller to realize remote computer control. Considerable improvements are also seen in the front-end plasma facing optics. This new optical system provides features including focusing, zoom, field curvature adjustment, and incident angle adjustment. These functions can be realized together or independently depending on the configuration setup of the large aperture lenses. This MIR system is expected to be installed on the EAST tokamak in December 2016, co-located with the Electron Cyclotron Emission Imaging (ECEI) system, to simultaneously measure electron density and temperature fluctuations. This work was supported by U.S. DOE Grant DE-FG02-99ER54531 and by the National MCF energy development program of China.

  17. Spherical tokamak development in Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Ludwig, G.O.; Del Bosco, E.; Ferreira, J.G.; Berni, L.A.; Oliveira, R.M.; Andrade, M.C.R.; Shibata, C.S.; Ueda, M.; Barroso, J.J.; Castro, P.J. [Instituto Nacional de Pesquisas Espaciais (INPE), Sao Jose dos Campos, SP (Brazil). Lab. Associado de Plasma; Barbosa, L.F.W. [Universidade do Vale do Paraiba (UNIVAP), Sao Jose dos Campos, SP (Brazil). Faculdade de Engenharia, Arquitetura e Urbanismo; Patire Junior, H. [Instituto Nacional de Pesquisas Espaciais (INPE), Sao Jose dos Campos, SP (Brazil). Div. de Mecanica Espacial e Controle; The high-power microwave sources group

    2003-12-01

    This paper describes the general characteristics of spherical tokamaks, or spherical tori, with a brief overview of work in this area already performed or in progress at several institutions worldwide. The paper presents also the steps in the development of the ETE (Experimento Tokamak Esferico) project, its research program, technical characteristics and operating conditions as of December, 2002 at the Associated Plasma Laboratory (LAP) of the National Space Research Institute (INPE) in Brazil. (author)

  18. Spherical tokamak development in Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Ludwig, Gerson Otto; Bosco, Edson Del; Ferreira, Julio Guimaraes [Instituto Nacional de Pesquisas Espaciais (INPE), Sao Jose dos Campos, SP (Brazil). Lab. Associado de Plasma] (and others)

    2003-07-01

    The general characteristics of spherical tokamaks, or spherical tori, with a brief view of work in this area already performed or in progress at several institutions worldwide are described. The paper presents also the steps in the development of the ETE (Experiment Tokamak spheric) project, its research program, technical characteristics and operating conditions as of December, 2002 a the Associated Plasma Laboratory (LAP) of the National Space Research Institute (INPE) in Brazil. (author)

  19. The ETE spherical Tokamak project

    Energy Technology Data Exchange (ETDEWEB)

    Ludwig, Gerson Otto; Andrade, Maria Celia Ramos de; Barbosa, Luis Filipe Wiltgen [Instituto Nacional de Pesquisas Espaciais (INPE), Sao Jose dos Campos, SP (Brazil). Lab. Associado de Plasma] [and others]. E-mail: ludwig@plasma.inpe.br

    1999-07-01

    This paper describes the general characteristics of spherical tokamaks, with a brief overview of work in the area of spherical torus already performed or in progress at several institutions. The paper presents also the historical development of the ETE (Spherical Tokamak Experiment) project, its research program, technical characteristics and status of construction in September, 1998 at the Associated plasma Laboratory (LAP) of the National Institute for Space Research (INPE) in Brazil. (author)

  20. The ARIES tokamak reactor study

    Energy Technology Data Exchange (ETDEWEB)

    1989-10-01

    The ARIES study is a community effort to develop several visions of tokamaks as fusion power reactors. The aims are to determine the potential economics, safety, and environmental features of a range of possible tokamak reactors, and to identify physics and technology areas with the highest leverage for achieving the best tokamak reactor. Three ARIES visions are planned, each having a different degree of extrapolation from the present data base in physics and technology. The ARIES-I design assumes a minimum extrapolation from current tokamak physics (e.g., 1st stability) and incorporates technological advances that can be available in the next 20 to 30 years. ARIES-II is a DT-burning tokamak which would operate at a higher beta in the 2nd MHD stability regime. It employs both potential advances in the physics and expected advances in technology and engineering. ARIES-II will examine the potential of the tokamak and the D{sup 3}He fuel cycle. This report is a collection of 14 papers on the results of the ARIES study which were presented at the IEEE 13th Symposium on Fusion Engineering (October 2-6, 1989, Knoxville, TN). This collection describes the ARIES research effort, with emphasis on the ARIES-I design, summarizing the major results, the key technical issues, and the central conclusions.

  1. 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 ...

  2. 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 current drive efficiency...

  3. 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...

  4. Fast ion measurements by collective Thomson scattering in TEXTOR and ASDEX Upgrade and proposal for the ITER CTS system

    DEFF Research Database (Denmark)

    Korsholm, Søren Bang; Bindslev, Henrik; Furtula, Vedran;

    Moving towards the era of burning fusion plasmas, a better knowledge of the physics of highly energetic particles, such as fusion born alpha particles, becomes essential. Diagnosing the fast ions in a fusion plasma is a challenging task, but the technique of collective Thomson scattering (CTS......) provides the possibility of revealing the velocity distribution of the confined fast ions along a given direction – resolved both in time and space. Recently, the ITER baseline design has been expanded to include the enabling of the front end of a fast ion CTS diagnostic system resolving dynamics...... perpendicular to the magnetic field. The feasibility study and conceptual design of this diagnostic was provided by the CTS group at Risø DTU. The development of the ITER CTS diagnostic builds on the experiences and expertise gained from the construction and current operation of the CTS diagnostic systems...

  5. Investigation of inter-ELM ion heat transport in the H-mode pedestal of ASDEX Upgrade plasmas

    Science.gov (United States)

    Viezzer, E.; Fable, E.; Cavedon, M.; Angioni, C.; Dux, R.; Laggner, F. M.; Bernert, M.; Burckhart, A.; McDermott, R. M.; Pütterich, T.; Ryter, F.; Willensdorfer, M.; Wolfrum, E.; the ASDEX Upgrade Team; the EUROfusion MST1 Team

    2017-02-01

    The ion heat transport in the pedestal of H-mode plasmas is investigated in various H-mode discharges with different pedestal ion collisionalities. Interpretive modelling suggests that in all analyzed discharges the ion heat diffusivity coefficient, {χ\\text{i}} , in the pedestal is close to the neoclassical prediction within the experimental uncertainties. The impact of changing the deposition location of the electron cyclotron resonance heating on the ion heat transport has been studied. The effect on the background profiles is small. The pre-ELM (edge localized modes) edge profiles as well as the behaviour of the electron temperature and density, ion temperature and impurity toroidal rotation during the ELM cycle are very similar in discharges with on- and off-axis ECRH heating. No significant deviation of {χ\\text{i}} from neoclassics is observed when changing the ECRH deposition location to the plasma edge.

  6. Moving Divertor Plates in a Tokamak

    Energy Technology Data Exchange (ETDEWEB)

    S.J. Zweben, H. Zhang

    2009-02-12

    Moving divertor plates could help solve some of the problems of the tokamak divertor through mechanical ingenuity rather than plasma physics. These plates would be passively heated on each pass through the tokamak and cooled and reprocessed outside the tokamak. There are many design options using varying plate shapes, orientations, motions, coatings, and compositions.

  7. Fusion potential for spherical and compact tokamaks

    Energy Technology Data Exchange (ETDEWEB)

    Sandzelius, Mikael

    2003-02-01

    The tokamak is the most successful fusion experiment today. Despite this, the conventional tokamak has a long way to go before being realized into an economically viable power plant. In this master thesis work, two alternative tokamak configurations to the conventional tokamak has been studied, both of which could be realized to a lower cost. The fusion potential of the spherical and the compact tokamak have been examined with a comparison of the conventional tokamak in mind. The difficulties arising in the two configurations have been treated from a physical point of view concerning the fusion plasma and from a technological standpoint evolving around design, materials and engineering. Both advantages and drawbacks of either configuration have been treated relative to the conventional tokamak. The spherical tokamak shows promising plasma characteristics, notably a high {beta}-value but have troubles with high heat loads and marginal tritium breeding. The compact tokamak operates at a high plasma density and a high magnetic field enabling it to be built considerably smaller than any other tokamak. The most notable down-side being high heat loads and neutron transport problems. With the help of theoretical reactor studies, extrapolating from where we stand today, it is conceivable that the spherical tokamak is closer of being realized of the two. But, as this study shows, the compact tokamak power plant concept offers the most appealing prospect.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. LHC Upgrade Scenarios

    CERN Document Server

    Zimmermann, F

    2007-01-01

    The EU CARE-HHH and US-LARP studies for an LHC luminosity upgrade aim at increasing the peak luminosity by a factor of 10, to 1035 cm-2s-1. The luminosity can be raised by rebuilding the interaction regions (IRs) in combination with a consistent change of beam parameters. In addition to advanced low-beta quadrupoles, the upgraded IRs may accommodate other new elements such as slim s.c. dipoles or quadrupoles embedded deep inside the detectors, global low-angle crab cavities, and wire compensators of long-range beam-beam effects. Important constraints on the upgrade path are the maximum acceptable number of detector pile-up events, favoring many closely spaced bunches, and the heat load on the cold-magnet beam screens, pointing towards fewer and more intense bunches. In order to translate the increased peak luminosity into a correspondingly higher integrated luminosity, the upgrade of the LHC ring should be complemented by an upgrade of the injector complex. I will present preferred upgrade scenarios for the L...

  13. 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.

  14. MAST-Upgrade Divertor Facility and Assessing Performance of Long-Legged Divertors

    CERN Document Server

    Fishpool, G; Cunningham, G; Harrison, J; Katramados, I; Kirk, A; Kovari, M; Meyer, H; Scannell, R

    2013-01-01

    A potentially important feature in a divertor design for a high-power tokamak is an extended and expanded divertor leg. The upgrade to MAST will allow a wide range of such divertor leg geometries to be produced, and hence will allow the roles of greatly increased connection length and flux expansion to be experimentally tested. This will include testing the potential of the Super-X configuration [1]. The design process for the upgrade has required analysis of producing and controlling the magnetic configurations, and has included consideration of the roles that divertor closure and increasing magnetic connection length will play.

  15. An enhanced tokamak startup model

    Science.gov (United States)

    Goswami, Rajiv; Artaud, Jean-François

    2017-01-01

    The startup of tokamaks has been examined in the past in varying degree of detail. This phase typically involves the burnthrough of impurities and the subsequent rampup of plasma current. A zero-dimensional (0D) model is most widely used where the time evolution of volume averaged quantities determines the detailed balance between the input and loss of particle and power. But, being a 0D setup, these studies do not take into consideration the co-evolution of plasma size and shape, and instead assume an unchanging minor and major radius. However, it is known that the plasma position and its minor radius can change appreciably as the plasma evolves in time to fill in the entire available volume. In this paper, an enhanced model for the tokamak startup is introduced, which for the first time takes into account the evolution of plasma geometry during this brief but highly dynamic period by including realistic one-dimensional (1D) effects within the broad 0D framework. In addition the effect of runaway electrons (REs) has also been incorporated. The paper demonstrates that the inclusion of plasma cross section evolution in conjunction with REs plays an important role in the formation and development of tokamak startup. The model is benchmarked against experimental results from ADITYA tokamak.

  16. 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.

  17. 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.

  18. HIRFL Operation and Upgrade

    Institute of Scientific and Technical Information of China (English)

    ZhaoHongwei; WangYifang; ZhanWenlong; WeiBaowen; HIRFLTeam

    2003-01-01

    After almost one year shutdown for upgrading the vacuum chamber of the iniector SFC,SFC has been in operation separately since May 2003. The SFC operation statistics and accelerated heams from May to December 2003 are shown in Table 1 and 2. The main cyclotron SSC has beenfor still shut down in 2003 for upgrading the SSC power supply system, control and diagnostic system, and themain experimental area, LECR3, an ECR ion source dedicated for atomic physics and surface physics research, has provided 2488 hours beams for experiments of atomic physics research.

  19. The UKIRT Upgrades Programme

    Science.gov (United States)

    Adamson, Andy; Davies, John; Robson, Ian

    Tim Hawarden presented this paper to the 30th anniversary workshop, just a month before his untimely death. The editors have done their best to convert his talk into this paper, and gratefully acknowledge the assistance of Nick Rees (a member of the Upgrades team, now at Diamond Light Source). Tim's discussion concerned the UKIRT Upgrades Project, which ran through the 1990s and transformed the telescope and made it truly competitive on the world stage for operation into the twenty-first century. The reference list at the end of the paper is comprehensive; some of these are referred to in the paper itself and some are included for completeness only.

  20. ATLAS/CMS Upgrades

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00370685; 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.

  1. 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

  2. LHCb VELO upgrade

    Science.gov (United States)

    Hennessy, Karol

    2017-02-01

    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 2×1033 cm-2 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 55×55 μm2 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, separated from the beam vacuum by a thin custom made foil. The foil will be manufactured through milling and possibly thinned further by chemical etching. The material budget will be minimised by the use of evaporative CO2 coolant circulating in microchannels within 400 μm thick silicon substrates. The current status of the VELO upgrade is described and latest results from operation of irradiated sensor assemblies are presented.

  3. 3D-MAPTOR Code for computation of magnetic fields in tokamaks

    Science.gov (United States)

    ChÁVez-AlarcÓN, Esteban; Herrera-VelÁZquez, Julio

    2009-11-01

    A 3dimensional code has been developed in order to determine the magnetic field in tokamaks, starting from the assumption that the toroidal and vertical field coils are all circular, as well as the cross section of the plasma current distribution. It was earlier used to study the stochastization of the outer magnetic surfaces [1] and to reconstruct the evolution of the plasma column, using the experimental signals of tokamak discharges. These results were compared with tomographic reconsructions of the ISTTOK tokamak [2]. We present an upgrade of the code, in which rectangular toroidal field coils and D shaped plasma current cross sections can be included. The code is particularly useful to study the effect of the ripple along the toroidal coordinate.[4pt] [1] E. Ch'avez, et al., ``Stochastization of Magnetic Field Surfaces in Tokamaks by an Inner Coil'' in Plasma and Fusion Science, AIP Conference Proceedings Series 875 (2006) pp.347-349.[0pt] [2] B.B. Carvalho, et al., ``Real-time plasma control based on the ISTTOK tomography diagnostic'', Rev. Sci. Instrum. 79 (2008)10F329.

  4. A compact Tokamak transmutation reactor

    Institute of Scientific and Technical Information of China (English)

    QiuLi-Jian; XiaoBing-Jia

    1997-01-01

    The low aspect ration tokamak is proposed for the driver of a transmutation reactor.The main parameters of the reactor core,neutronic analysis of the blanket are given>the neutron wall loading can be lowered from the magnitude order of 1 MW/m2 to 0.5MW/m2 which is much easier to reach in the near future,and the transmutation efficiency (fission/absorption ratio)is raised further.The blanket power density is about 200MW/m3 which is not difficult to deal with.The key components such as diverter and center conductor post are also designed and compared with conventional TOkamak,Finally,by comparison with the other drivers such as FBR,PWR and accelerator,it can be anticipated that the low aspect ratio transmutation reactor would be one way of fusion energy applications in the near future.

  5. Bootstrap Current in Spherical Tokamaks

    Institute of Scientific and Technical Information of China (English)

    王中天; 王龙

    2003-01-01

    Variational principle for the neoclassical theory has been developed by including amomentum restoring term in the electron-electron collisional operator, which gives an additionalfree parameter maximizing the heat production rate. All transport coefficients are obtained in-cluding the bootstrap current. The essential feature of the study is that the aspect ratio affects thefunction of the electron-electron collision operator through a geometrical factor. When the aspectratio approaches to unity, the fraction of circulating particles goes to zero and the contribution toparticle flux from the electron-electron collision vanishes. The resulting diffusion coefficient is inrough agreement with Hazeltine. When the aspect ratio approaches to infinity, the results are inagreement with Rosenbluth. The formalism gives the two extreme cases a connection. The theoryis particularly important for the calculation of bootstrap current in spherical tokamaks and thepresent tokamaks, in which the square root of the inverse aspect ratio, in general, is not small.

  6. Cryogenic needs for future tokamaks

    Science.gov (United States)

    Katheder, H.

    The ITER tokamak is a machine using superconducting magnets. The windings of these magnets will be subjected to high heat loads resulting from a combination of nuclear energy absorption and AC-losses. It is estimated that about 100 kW at 4.5 K are needed. The total cooling mass flow rate will be around 10 - 15 kg/s. In addition to the large cryogenic power required for the superconducting magnets cryogenic power is also needed for refrigerated radiation shield, various cryopumps, fuel processing and test beds. A general description of the overall layout and the envisaged refrigerator cycle, necessary cold pumps and ancillary equipment is given. The basic cryogenic layout for the ITER tokakmak design, as developed during the conceptual design phase and a short overview about existing tokamak designs using superconducting magnets is given.

  7. Options for an ignited tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Sheffield, J.

    1984-02-01

    It is expected that the next phase of the fusion program will involve a tokamak with the goals of providing an ignited plasma for pulses of hundreds of seconds. A simple model is described in this memorandum which establishes the physics conditions for such a self-sustaining plasma, for given ion and electron thermal diffusivities, in terms of R/a, b/a, I, B/q, epsilon ..beta../sub p/, anti T/sub i/, and anti T/sub e//anti T/sub i/. The model is used to produce plots showing the wide range of tokamaks that may ignite or have a given ignition margin. The constraints that limit this range are discussed.

  8. Magnetic confinement experiment. I: Tokamaks

    Energy Technology Data Exchange (ETDEWEB)

    Goldston, R.J.

    1995-08-01

    Reports were presented at this conference of important advances in all the key areas of experimental tokamak physics: Core Plasma Physics, Divertor and Edge Physics, Heating and Current Drive, and Tokamak Concept Optimization. In the area of Core Plasma Physics, the biggest news was certainly the production of 9.2 MW of fusion power in the Tokamak Fusion Test Reactor, and the observation of unexpectedly favorable performance in DT plasmas. There were also very important advances in the performance of ELM-free H- (and VH-) mode plasmas and in quasi-steady-state ELM`y operation in JT-60U, JET, and DIII-D. In all three devices ELM-free H-modes achieved nT{tau}`s {approximately} 2.5x greater than ELM`ing H-modes, but had not been sustained in quasi-steady-state. Important progress has been made on the understanding of the physical mechanism of the H-mode in DIII-D, and on the operating range in density for the H-mode in Compass and other devices.

  9. Aligning component upgrades

    Directory of Open Access Journals (Sweden)

    Roberto Di Cosmo

    2011-08-01

    Full Text Available Modern software systems, like GNU/Linux distributions or Eclipse-based development environment, are often deployed by selecting components out of large component repositories. Maintaining such software systems by performing component upgrades is a complex task, and the users need to have an expressive preferences language at their disposal to specify the kind of upgrades they are interested in. Recent research has shown that it is possible to develop solvers that handle preferences expressed as a combination of a few basic criteria used in the MISC competition, ranging from the number of new components to the freshness of the final configuration. In this work we introduce a set of new criteria that allow the users to specify their preferences for solutions with components aligned to the same upstream sources, provide an efficient encoding and report on the experimental results that prove that optimising these alignment criteria is a tractable problem in practice.

  10. Gemini Instrument Upgrade Program

    Science.gov (United States)

    Diaz, Ruben; Goodsell, Stephen; Kleinman, Scot

    2016-08-01

    The Gemini Observatory* remains committed to keeping its operational instrumentation competitive and serving the needs of its user community. Currently the observatory operates a 4 instruments + 1 AO system at each site. At Gemini North the GMOS-N, GNIRS, NIFS and NIRI instruments are offered supported by the ALTAIR AO system. In the south, GMOS-S, F-2, GPI and GSAOI are offered instrumentation and GeMS is the provided AO System. This paper reviews our strategy to keep our instrumentation suite competitive, examines both our current funded upgrade projects and our potential future enhancements. We summarize the work done and the results so far obtained within the instrument upgrade program.

  11. Major upgrade of the articulated inspection arm control system to fulfill daily operation requirements

    Energy Technology Data Exchange (ETDEWEB)

    Pastor, P., E-mail: patrick.pastor@cea.fr [CEA, IRFM, Institut de Recherche sur la Fusion par confinement Magnétique (France); Villedieu, E.; Allegretti, L.; Vincent, B.; Barbuti, A.; Bruno, V.; Coquillat, P.; Dechelle, C.; Gargiulo, L.; Le, R.; Malard, P.; Martinez, A.; Nouailletas, R. [CEA, IRFM, Institut de Recherche sur la Fusion par confinement Magnétique (France); Yuntao, Song; Yong, Cheng; Chen, Liu; Hansheng, Feng; Shanshuang, Shi [ASIPP, Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, Anhui (China)

    2015-10-15

    Highlights: • We propose an overview of the work which has been done to upgrade the control system of the AIA robot (articulated inspection arm) to fulfill daily operation requirements for tokamak inspection. • The control system is based on the use of new position sensors, new electronics design and new supervisor software. • Final tests are ongoing in the EAST scale 1 tokamak mock-up. Routine operation of the robot at EAST will start in the beginning of 2015. - Abstract: An articulated inspection arm (AIA) has been developed by CEA for visual inspection between pulses inside the Tore Supra tokamak vacuum vessel without breaking temperature and vacuum conditions. The eight meters length robot is composed of a shuttle and six articulated segments with a video camera at its end. A demonstration prototype has been achieved in 2008 at Tore Supra (Gargiulo, 2007; Houry, 2008; Perrot, 2003). A project to upgrade the AIA into a fully operational robot has been undertaken by IRFM and ASIPP in an Associated Laboratory. It will be in operation first in the EAST machine and afterwards in Tore Supra in its WEST (W/Tungsten Environment in Steady-state Tokamak) configuration where it is of paramount importance to survey possible degradation of W component surface. The control system of the robot has been extensively upgraded. The effort has been focused on three areas: (1) improvement of the arm position accuracy, (2) increase of the operational robustness, (3) use of a powerful graphical user interface including simulation of trajectories and robot deployment capabilities in a 3D viewer environment. The aim of this paper is to detail the architecture of the AIA control system.

  12. The VELO Upgrade

    CERN Document Server

    Jans, Eddy

    2015-01-01

    A significant upgrade of the LHCb detector is scheduled to be installed in 2018-2019. Afterwards all sub-detectors will be read out at the LHC bunch crossing frequency of 40 MHz and the trigger will be fully implemented in software. The silicon strip vertex detector will be replaced by a hybrid pixel detector. In these proceedings the following items are discussed: frontend ASIC, data rates, data transmission, cooling, radiation hard sensors, module design and simulated performance.

  13. CMS upgrades for SLHC

    CERN Document Server

    Palla, Fabrizio

    2006-01-01

    I will discuss the impact of the LHC luminosity upgrade on CMS detector. While most of the CMS can possibly cope with the increased luminosity, the Tracker must undergo a major redesign in technology both in terms of detector substrates as well as in the data transfer links. I will show the impact on CMS of reduced bunch length and machine elements close to the interaction point.

  14. 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...

  15. ATLAS Upgrade Plans

    CERN Document Server

    Hopkins, W; The ATLAS collaboration

    2014-01-01

    After the successful LHC operation at the center-of-mass energies of 7 and 8 TeV in 2010-2012, 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 final goal is to extend the dataset from about few hundred fb−1 expected for LHC running to 3000/fb 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. Current planning in ATLAS envisions significant upgrades to the detector during the consolidation of the LHC to reach full LHC energy and further upgrades. The challenge of coping with the HL-LHC instantaneous and integrated luminosity, along with the associated radiation levels, requires further major changes to the ATLAS detector. The designs are developing rapidly for a new...

  16. The role of limiter in Egyptor Tokamak

    CERN Document Server

    Ei-Sisi, A B

    2002-01-01

    In Egyptor Tokamak, the limiter is used for separation of the plasma from the vessel. In this work an overview of limiter types, and construction of limiter in Egyptor Tokamak is discussed. Also simulation results of the radial electron density distribution in case of limiter are presented. The results of the simulation are in agreement with the experimental and analytical results.

  17. Big Dee upgrade of the Doublet III diagnostic data acquisition computer system

    Energy Technology Data Exchange (ETDEWEB)

    McHarg, B.B. Jr.

    1983-12-01

    The Big Dee upgrade of the Doublet III tokamak facility will begin operation in 1986 with an initial quantity of data expected to be 10 megabytes per shot and eventually attaining 20 to 25 megabytes per shot. This is in comparison to the 4 to 5 megabytes of data currently acquired. To handle this greater quantity of data and to serve physics needs for significantly improved between-shot processing of data will require a substantial upgrade of the existing data acquisition system. The key points of the philosophy that have been adopted for the upgraded system to handle the greater quantity of data are (1) preserve existing hardware; (2) preserve existing software; (3) configure the system in a modular fashion; and (4) distribute the data acquisition over multiple computers. The existing system using ModComp CLASSIC 16 bit minicomputers is capable of handling 5 megabytes of data per shot.

  18. A real-time data acquisition and elaboration system for instabilities control in the FTU tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Alessi, E., E-mail: alessi@ifp.cnr.it [Associazione EURATOM-ENEA, IFP-CNR, Milano (Italy); Boncagni, L. [Associazione EURATOM-ENEA, C.R. Frascati (Italy); Galperti, C.; Marchetto, C.; Nowak, S.; Sozzi, C. [Associazione EURATOM-ENEA, IFP-CNR, Milano (Italy); Apruzzese, G. [Associazione EURATOM-ENEA, C.R. Frascati (Italy); Bin, W. [Associazione EURATOM-ENEA, IFP-CNR, Milano (Italy); Belli, F.; Botrugno, A. [Associazione EURATOM-ENEA, C.R. Frascati (Italy); Bruschi, A.; Cirant, S. [Associazione EURATOM-ENEA, IFP-CNR, Milano (Italy); D' Antona, G.; Davoudi, M. [Politecnico di Milano, Dipartimento di Elettrotecnica (Italy); Figini, L. [Associazione EURATOM-ENEA, IFP-CNR, Milano (Italy); Ferrero, R. [Politecnico di Milano, Dipartimento di Elettrotecnica (Italy); Gabellieri, L. [Associazione EURATOM-ENEA, C.R. Frascati (Italy); Garavaglia, S.; Granucci, G. [Associazione EURATOM-ENEA, IFP-CNR, Milano (Italy); Grosso, A. [Associazione EURATOM-ENEA, C.R. Frascati (Italy); and others

    2013-08-21

    A real-time data acquisition and elaboration system is being implemented to control the new ECH launcher recently installed at FTU (Frascati Tokamak Upgrade). The system is aimed at controlling different kinds of magnetohydrodynamic instabilities, in particular the deleterious 3/2 and 2/1 (neoclassical) tearing modes, (N)TM, and the saw teeth period in order to prevent the seeding of NTMs. The complete system is presented here together with preliminary offline and real-time tests. © 2001 Elsevier Science. All rights reserved.

  19. Performance of V-4Cr-4Ti material exposed to the DIII-D tokamak environment

    Energy Technology Data Exchange (ETDEWEB)

    Tsai, H.; Smith, D.L.; Chung, H.M. [Argonne National Lab., IL (United States); Johnson, W.R.; Smith, J.P. [General Atomics, San Diego, CA (United States); Wampler, W.R. [Sandia National Labs. (United States)

    1998-03-01

    A series of tests is being conducted in the DIII-D tokamak to determine the effects of environmental exposure on a V-4Cr-4Ti vanadium alloy. These tests are part of the effort to build and install a water-cooled vanadium V alloy structure in the upgrade of the DIII-D radiative divertor. Data from the test series indicate that the performance of the V-4Cr-4Ti alloy would not be significantly affected by environmental exposure. Interstitial absorption by the material appears to be limited to the surface, and neither the tensile nor the impact properties of the material appear to be affected by the exposure.

  20. Development and Application of Predictive Tools for MHD Stability Limits in Tokamaks

    Energy Technology Data Exchange (ETDEWEB)

    Brennan, Dylan [Princeton Univ., NJ (United States); Miller, G. P. [Univ. of Tulsa, Tulsa, AZ (United States)

    2016-10-03

    This is a project to develop and apply analytic and computational tools to answer physics questions relevant to the onset of non-ideal magnetohydrodynamic (MHD) instabilities in toroidal magnetic confinement plasmas. The focused goal of the research is to develop predictive tools for these instabilities, including an inner layer solution algorithm, a resistive wall with control coils, and energetic particle effects. The production phase compares studies of instabilities in such systems using analytic techniques, PEST- III and NIMROD. Two important physics puzzles are targeted as guiding thrusts for the analyses. The first is to form an accurate description of the physics determining whether the resistive wall mode or a tearing mode will appear first as β is increased at low rotation and low error fields in DIII-D. The second is to understand the physical mechanism behind recent NIMROD results indicating strong damping and stabilization from energetic particle effects on linear resistive modes. The work seeks to develop a highly relevant predictive tool for ITER, advance the theoretical description of this physics in general, and analyze these instabilities in experiments such as ASDEX Upgrade, DIII-D, JET, JT-60U and NTSX. The awardee on this grant is the University of Tulsa. The research efforts are supervised principally by Dr. Brennan. Support is included for two graduate students, and a strong collaboration with Dr. John M. Finn of LANL. The work includes several ongoing collaborations with General Atomics, PPPL, and the NIMROD team, among others.

  1. Upgraded Coal Interest Group

    Energy Technology Data Exchange (ETDEWEB)

    Evan Hughes

    2009-01-08

    The Upgraded Coal Interest Group (UCIG) is an EPRI 'users group' that focuses on clean, low-cost options for coal-based power generation. The UCIG covers topics that involve (1) pre-combustion processes, (2) co-firing systems and fuels, and (3) reburn using coal-derived or biomass-derived fuels. The UCIG mission is to preserve and expand the economic use of coal for energy. By reducing the fuel costs and environmental impacts of coal-fired power generation, existing units become more cost effective and thus new units utilizing advanced combustion technologies are more likely to be coal-fired.

  2. Anomalous particle pinch in Tokamaks

    Energy Technology Data Exchange (ETDEWEB)

    Miskane, F.; Garbet, X. [Association Euratom-CEA/Cadarache, Dept. de Recherches sur la Fusion Controlee, DRFC, 13 - Saint-Paul-lez-Durance (France); Dezairi, A.; Saifaoui, D. [Faculte des Sciences Ain Chok, Casablanca (Morocco)

    2000-06-01

    The diffusion coefficient in phase space usually varies with the particle energy. A consequence is the dependence of the fluid particle flux on the temperature gradient. If the diffusion coefficient in phase space decreases with the energy in the bulk of the thermal distribution function, the particle thermodiffusion coefficient which links the particle flux to the temperature gradient is negative. This is a possible explanation for the inward particle pinch that is observed in tokamaks. A quasilinear theory shows that such a thermodiffusion is generic for a tokamak electrostatic turbulence at low frequency. This effect adds to the particle flux associated with the radial gradient of magnetic field. This behavior is illustrated with a perturbed electric potential, for which the trajectories of charged particle guiding centers are calculated. The diffusion coefficient of particles is computed and compared to the quasilinear theory, which predicts a divergence at low velocity. It is shown that at low velocity, the actual diffusion coefficient increases, but remains lower than the quasilinear value. Nevertheless, this differential diffusion between cold and fast particles leads to an inward flux of particles. (author)

  3. ATLAS Detector Upgrade Prospects

    CERN Document Server

    Dobre, Monica; The ATLAS collaboration

    2016-01-01

    After the successful operation at the centre-of-mass energies of 7 and 8 TeV in 2010-2012, the LHC is ramped up and successfully took data at the centre-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 levelling. The ultimate goal is to extend the dataset from about few hundred f b −1 expected for LHC running to 3000 f b −1 by around 2035 for ATLAS and CMS. The challenge of coping with the HL-LHC instantaneous and integrated luminosity, along with the associated radiation levels, requires further major changes to the ATLAS detector. The designs are developing rapidly for a new all-silicon tracker, significant upgrades of the calorimeter and muon systems, as well as improved triggers and data acquisition. ATLAS is also examining potential benefits of ext...

  4. ATLAS Detector Upgrade Prospects

    CERN Document Server

    Dobre, Monica; 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. The challenge of coping with the HL-LHC instantaneous and integrated luminosity, along with the associated radiation levels, requires further major changes to the ATLAS detector. The designs are developing rapidly for a new all-silicon tracker, significant upgrades of the calorimeter and muon systems, as well as improved triggers and data acquisition. ATLAS is also examining potential benefits of extens...

  5. ATLAS Detector Upgrade Prospects

    Science.gov (United States)

    Dobre, M.; ATLAS Collaboration

    2017-01-01

    After the successful operation at the centre-of-mass energies of 7 and 8 TeV in 2010-2012, the LHC was ramped up and successfully took data at the centre-of-mass energies of 13 TeV in 2015 and 2016. 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, which will deliver of the order of five times the LHC nominal instantaneous luminosity along with luminosity levelling. The ultimate goal is to extend the dataset from about few hundred fb ‑1 expected for LHC running by the end of 2018 to 3000 fb ‑1 by around 2035 for ATLAS and CMS. The challenge of coping with the HL-LHC instantaneous and integrated luminosity, along with the associated radiation levels, requires further major changes to the ATLAS detector. The designs are developing rapidly for a new all-silicon tracker, significant upgrades of the calorimeter and muon systems, as well as improved triggers and data acquisition. ATLAS is also examining potential benefits of extensions to larger pseudorapidity, particularly in tracking and muon systems. This report summarizes various improvements to the ATLAS detector required to cope with the anticipated evolution of the LHC luminosity during this decade and the next. A brief overview is also given on physics prospects with a pp centre-of-mass energy of 14 TeV.

  6. 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...

  7. Tokamak Plasmas : Mirnov coil data analysis for tokamak ADITYA

    Indian Academy of Sciences (India)

    D Raju; R Jha; P K Kaw; S K Mattoo; Y C Saxena; Aditya Team

    2000-11-01

    The spatial and temporal structures of magnetic signal in the tokamak ADITYA is analysed using recently developed singular value decomposition (SVD) technique. The analysis technique is first tested with simulated data and then applied to the ADITYA Mirnov coil data to determine the structure of current peturbation as the discharge progresses. It is observed that during the current rise phase, current perturbation undergoes transition from = 5 poloidal structure to = 4 and then to = 3. At the time of current termination, = 2 perturbation is observed. It is observed that the mode frequency remains nearly constant (≈10 kHz) when poloidal mode structure changes from = 4 to = 2. This may be either an indication of mode coupling or a consequences of changes in the plasma electron temperature and density scale length.

  8. Recent results from the DIII-D tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Petersen, P.I.

    1998-02-01

    The DIII-D national fusion research program focuses on establishing the scientific basis for optimization of the tokamak approach to fusion energy production. The symbiotic development of research, theory, and hardware continues to fuel the success of the DIII-D program. During the last year, a radiative divertor and a second cryopump were installed in the DIII-D vacuum vessel, an array of central and boundary diagnostics were added, and more sophisticated computer models were developed. These new tools have led to substantial progress in the understanding of the plasma. The authors now have a better understanding of the divertor as a means to manage the heat, particle, and impurity transport pumping of the plasma edge using the in situ divertor cryopumps effectively controls the plasma density. The evolution of diagnostics that probe the interior of the plasma, particularly the motional Stark effect diagnostic, has led to a better understanding of the core of the plasma. This understanding, together with tools to control the profiles, including electron cyclotron waves, pellet injection, and neutral beam injection, has allowed them to progress in making plasma configurations that give rise to both low energy transport and improved stability. Most significant here is the use of transport barriers to improve ion confinement to neoclassical values. Commissioning of the first high power (890 kW) 110 GHz gyrotron validates an important tool for managing the plasma current profile, key to maintaining the transport barriers. An upgraded plasma control system, ``isoflux control,`` which exploits real time MHD equilibrium calculations to determine magnetic flux at specified locations within the tokamak vessel and provides the means for precisely controlling the plasma shape and, in conjunction with other heating and fueling systems, internal profiles.

  9. Upgrade trigger: Biannual performance update

    CERN Document Server

    Aaij, Roel; Couturier, Ben; Esen, Sevda; De Cian, Michel; De Vries, Jacco Andreas; Dziurda, Agnieszka; Fitzpatrick, Conor; Fontana, Marianna; Grillo, Lucia; Hasse, Christoph; Jones, Christopher Rob; Le Gac, Renaud; Matev, Rosen; Neufeld, Niko; Nikodem, Thomas; Polci, Francesco; Del Buono, Luigi; Quagliani, Renato; Schwemmer, Rainer; Seyfert, Paul; Stahl, Sascha; Szumlak, Tomasz; Vesterinen, Mika Anton; Wanczyk, Joanna; Williams, Mark Richard James; Yin, Hang; Zacharjasz, Emilia Anna

    2017-01-01

    This document presents the performance of the LHCb Upgrade trigger reconstruction sequence, incorporating changes to the underlying reconstruction algorithms and detector description since the Trigger and Online Upgrade TDR. An updated extrapolation is presented using the most recent example of an Event Filter Farm node.

  10. OPTIMUM PLASMA STATES FOR NEXT STEP TOKAMAKS

    Energy Technology Data Exchange (ETDEWEB)

    LIN-LIU,YR; STAMBAUGH,RD

    2002-11-01

    OAK A271 OPTIMUM PLASMA STATES FOR NEXT STEP TOKAMAKS. The dependence of the ideal ballooning {beta} limit on aspect ratio, A, and elongation {kappa} is systematically explored for nearly 100% bootstrap current driven tokamak equilibria in a wide range of the shape parameters (A = 1.2-7.0, {kappa} = 1.5-6.0 with triangularity {delta} = 0.5). The critical {beta}{sub N} is shown to be optimal at {kappa} = 3.0-4.0 for all A studied and increases as A decreases with a dependence close to A{sup -0.5}. The results obtained can be used as a theoretical basis for the choice of optimum aspect ratio and elongation of next step burning plasma tokamaks or tokamak reactors.

  11. LHCb: The LHCb Upgrade

    CERN Multimedia

    Borghi, Silvia

    2012-01-01

    The LHCb experiment is designed to perform high-precision measurements of CP violation and search for New Physics using the enormous flux of beauty and charmed hadrons 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 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, especially in the hadronic channels

  12. The ETE spherical Tokamak project. IAEA report

    Energy Technology Data Exchange (ETDEWEB)

    Ludwig, Gerson Otto; Del Bosco, E.; Berni, L.A.; Ferreira, J.G.; Oliveira, R.M.; Andrade, M.C.R.; Shibata, C.S.; Barroso, J.J.; Castro, P.J.; Patire Junior, H. [Instituto Nacional de Pesquisas Espaciais (INPE), Sao Jose dos Campos, SP (Brazil). Lab. Associado de Plasma]. E-mail: ludwig@plasma.inpe.br

    2002-07-01

    This paper describes the general characteristics of spherical tokamaks, or spherical tori, with a brief overview of work in this area already performed or in progress at several institutions worldwide. The paper presents also the historical development of the ETE (Spherical Tokamak Experiment) project, its research program, technical characteristics and operating conditions as of October, 2002 at the Associated Plasma Laboratory (LAP) of the National Space Research Institute (INPE) in Brazil. (author)

  13. D-D tokamak reactor studies

    Energy Technology Data Exchange (ETDEWEB)

    Evans, K.E. Jr.; Baker, C.C.; Brooks, J.N.; Ehst, D.A.; Finn, P.A.; Jung, J.; Mattas, R.F.; Misra, B.; Smith, D.L.; Stevens, H.C.

    1980-11-01

    A tokamak D-D reactor design, utilizing the advantages of a deuterium-fueled reactor but with parameters not unnecessarily extended from existing D-T designs, is presented. Studies leading to the choice of a design and initial studies of the design are described. The studies are in the areas of plasma engineering, first-wall/blanket/shield design, magnet design, and tritium/fuel/vacuum requirements. Conclusions concerning D-D tokamak reactors are stated.

  14. The RHIC polarized source upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Zelenski, A.; Atoian, G.; Davydenko, V.; Ivanov, A.; Kolmogorov, A.; Ritter, J.; Steski, D.; Zubets, V.

    2010-09-27

    The RHIC polarized H{sup -} ion source is being upgraded to higher intensity (5-10 mA) and polarization for use in the RHIC polarization physics program at enhanced luminosity RHIC operation. The higher beam peak intensity will allow reduction of the transverse beam emittance at injection to AGS to reduce polarization losses in AGS. There is also a planned RHIC luminosity upgrade by using the electron beam lens to compensate the beam-beam interaction at collision points. This upgrade is also essential for future BNL plans for a high-luminosity electron - proton (ion) Collider eRHIC.

  15. Analysis of NSTX Upgrade OH Magnet and Center Stack

    Energy Technology Data Exchange (ETDEWEB)

    A. Zolfaghari, P. Titus, J. Chrzanowski, A. Salehzadeh, F. Dahlgren

    2010-11-30

    The new ohmic heating (OH) coil and center stack for the National Spherical Torus Experiment (NSTX) upgrade are required to meet cooling and structural requirements for operation at the enhanced 1 Tesla toroidal field and 2 MA plasma current. The OH coil is designed to be cooled in the time between discharges by water flowing in the center of the coil conductor. We performed resistive heating and thermal hydraulic analyses to optimize coolant channel size to keep the coil temperature below 100 C and meet the required 20 minute cooling time. Coupled electromagnetic, thermal and structural FEA analyses were performed to determine if the OH coil meets the requirements of the structural design criteria. Structural response of the OH coil to its self-field and the field from other coils was analyzed. A model was developed to analyze the thermal and electromagnetic interaction of centerstack components such as the OH coil, TF inner legs and the Bellville washer preload mechanism. Torsional loads from the TF interaction with the OH and poloidal fields are transferred through the TF flag extensions via a torque transfer coupling to the rest of the tokamak structure. A 3D FEA analysis was performed to qualify this design. The results of these analyses, which will be presented in this paper, have led to the design of OH coil and centerstack components that meet the requirements of the NSTX-upgrade structural design criteria.

  16. Superhilac upgrade project

    Energy Technology Data Exchange (ETDEWEB)

    Feinberg, B.; Brown, I.G.

    1985-05-01

    This project will increase the uranium output of the Bevalac heavy-ion facility from the currently available 10/sup 7/ to 5 x 10/sup 7/ ions/pulse, allowing accurate Lamb shift measurements to be made in U/sup 90 +/ and U/sup 91 +/ with important applications to the testing of quantum electrodynamics and the development of an x-ray laser. The injected beam intensity will be increased to make better use of the 10emA output space-charge limit of the Wideroe linac. Components will include a new high current MEtal Vapor Vacuum Arc (MEVVA) ion source along with an improved high current, high voltage Cockcroft-Walton power supply to handle the increased beam current. The Low Energy Beam Transport (LEBT) line will be upgraded with additional focusing to manage the increased space-charge forces and with an improved vacuum to reduce charge exchange losses. Finally, the phase matching between the 23MHz Wideroe linac and the 70MHz Alvarez linac will be improved by the addition of the appropriate buncher cavities. Physics design is underway and detailed engineering is scheduled to begin in October 1985, with installation slated for the 1986 summer shutdown.

  17. The LHCb Upgrade

    CERN Document Server

    Gallas, A

    2012-01-01

    The LHCb experiment is designed to perform high-precision measurements of CP violation and search for New Physics using the enormous flux of beauty and charmed hadrons produced at the LHC. The LHCb detector is a single-arm spectrometer with excellent tracking and particle identification capabilities. The operation and the results obtained from the data collected in 2010 and 2011 demonstrate that the detector is robust and functioning very well. In the next years, LHCb will measure a large number of interesting channels in heavy flavor decays. However, the limit of 1 fb−1 of data per year cannot be overcome without improving the detector. An upgraded spectrometer with a 40MHz readout and a much more flexible software-based triggering system will increase the data rate as well as the efficiency specially in the hadronic channels, widening our physics scope beyond that of heavy flavor. Here, the different possibilities under study for the different detectors are reviewed as well as the ongoing R&D activiti...

  18. 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...

  19. Altair performance and upgrades

    Science.gov (United States)

    Lai, Olivier; Véran, Jean-Pierre; Herriot, Glen; White, John; Ball, Jesse; Trujillo, Chad

    2014-07-01

    Altair is the facility single conjugate AO system for Gemini North. Although it has been in operation for more than 10 years (and upgraded to LGS in 2007), Altair's performance is degraded by three main issues: vibrations of the telescope and instrument support structure, spatial aliasing on centroid offsets from the M2 support structure print-through on the optical surface and static non-common path aberrations. Monte-Carlo simulations can reproduce the behavior of Altair when including these three effects and they are roughly of the same order of magnitude. Solutions or mitigations are being investigated to overcome these nefarious effects and restore Altair's performance to its nominal level. A simplex algorithm as well as a phase diversity approach are being investigated to measure and correct for static aberrations. A high accuracy phase map of the M2 print-through has been obtained and is being used to calibrate and/or filter centroids affected by aliasing. A new real time computer is under consideration, to be able to handle more advanced controllers, especially notch filters to combat vibrations. In this paper we will report on the various simulations and on-sky results of this rejuvenation of one of Gemini's workhorse instruments.

  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. 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.

  2. Vacuum System for HL-2A Tokamak

    Institute of Scientific and Technical Information of China (English)

    曹曾; 崔成和; 刘德权; 蔡萧; 高霄燕

    2005-01-01

    The vacuum system for HL-2A was built in 2003. The test results indicated that this system is feasible. It consists of three main parts: a pumping system, a pumping divertor and a glow discharge cleaning (GDC) system. For the pumping system, there are three main functions:(1) evacuating the vacuum vessel thus to produce an ultra high vacuum, (2) removal of impurities released during baking and (3) pumping during GDC. The pumping divertor controls the particles at the plasma edge and the GDC system provides a clean wall conditioning. During the first campaign of physical trial experiment on HL-2A, the ultimate pressure reached 4.6×10-6 Pa, and of ASDEX.

  3. Characteristics of Plasma Turbulence in the Mega Amp Spherical Tokamak

    CERN Document Server

    Ghim, Young-chul

    2013-01-01

    Turbulence is a major factor limiting the achievement of better tokamak performance as it enhances the transport of particles, momentum and heat which hinders the foremost objective of tokamaks. Hence, understanding and possibly being able to control turbulence in tokamaks is of paramount importance, not to mention our intellectual curiosity of it.

  4. Electron thermal transport in tokamak plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Konings, J.A.

    1994-11-30

    The process of fusion of small nuclei thereby releasing energy, as it occurs continuously in the sun, is essential for the existence of mankind. The same process applied in a controlled way on earth would provide a clean and an abundant energy source, and be the long term solution of the energy problem. Nuclear fusion requires an extremely hot (10{sup 8} K) ionized gas, a plasma, that can only be maintained if it is kept insulated from any material wall. In the so called `tokamak` this is achieved by using magnetic fields. The termal insulation, which is essential if one wants to keep the plasma at the high `fusion` temperature, can be predicted using basic plasma therory. A comparison with experiments in tokamaks, however, showed that the electron enery losses are ten to hundred times larger than this theory predicts. This `anomalous transport` of thermal energy implies that, to reach the condition for nuclear fusion, a fusion reactor must have very large dimensions. This may put the economic feasibility of fusion power in jeopardy. Therefore, in a worldwide collaboration, physicists study tokamak plasmas in an attempt to understand and control the energy losses. From a scientific point of view, the mechanisms driving anomalous transport are one of the challenges in fudamental plasma physics. In Nieuwegein, a tokamak experiment (the Rijnhuizen Tokamak Project, RTP) is dedicated to the study of anomalous transport, in an international collaboration with other laboratories. (orig./WL).

  5. Microtearing modes in tokamak discharges

    Science.gov (United States)

    Rafiq, T.; Weiland, J.; Kritz, A. H.; Luo, L.; Pankin, A. Y.

    2016-06-01

    Microtearing modes (MTMs) have been identified as a source of significant electron thermal transport in tokamak discharges. In order to describe the evolution of these discharges, it is necessary to improve the prediction of electron thermal transport. This can be accomplished by utilizing a model for transport driven by MTMs in whole device predictive modeling codes. The objective of this paper is to develop the dispersion relation that governs the MTM driven transport. A unified fluid/kinetic approach is used in the development of a nonlinear dispersion relation for MTMs. The derivation includes the effects of electrostatic and magnetic fluctuations, arbitrary electron-ion collisionality, electron temperature and density gradients, magnetic curvature, and the effects associated with the parallel propagation vector. An iterative nonlinear approach is used to calculate the distribution function employed in obtaining the nonlinear parallel current and the nonlinear dispersion relation. The third order nonlinear effects in magnetic fluctuations are included, and the influence of third order effects on a multi-wave system is considered. An envelope equation for the nonlinear microtearing modes in the collision dominant limit is introduced in order to obtain the saturation level. In the limit that the mode amplitude does not vary along the field line, slab geometry, and strong collisionality, the fluid dispersion relation for nonlinear microtearing modes is found to agree with the kinetic dispersion relation.

  6. Up-down asymmetric tokamaks

    CERN Document Server

    Ball, Justin

    2016-01-01

    Bulk toroidal rotation has proven capable of stabilising both dangerous MHD modes and turbulence. In this thesis, we explore a method to drive rotation in large tokamaks: up-down asymmetry in the magnetic equilibrium. We seek to maximise this rotation by finding optimal up-down asymmetric flux surface shapes. First, we use the ideal MHD model to show that low order external shaping (e.g. elongation) is best for creating up-down asymmetric flux surfaces throughout the device. Then, we calculate realistic up-down asymmetric equilibria for input into nonlinear gyrokinetic turbulence analysis. Analytic gyrokinetics shows that, in the limit of fast shaping effects, a poloidal tilt of the flux surface shaping has little effect on turbulent transport. Since up-down symmetric surfaces do not transport momentum, this invariance to tilt implies that devices with mirror symmetry about any line in the poloidal plane will drive minimal rotation. Accordingly, further analytic investigation suggests that non-mirror symmetri...

  7. Global gyrokinetic simulation of tokamak transport

    Energy Technology Data Exchange (ETDEWEB)

    Furnish, G.; Horton, W.; Kishimoto, Y.; LeBrun, M.J.; Tajima, T. [Univ. of Texas, Austin, TX (United States). Inst. for Fusion Studies]|[Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan)

    1998-10-01

    A kinetic simulation code based on the gyrokinetic ion dynamics in global general metric (including a tokamak with circular or noncircular cross-section) has been developed. This gyrokinetic simulation is capable of examining the global and semi-global driftwave structures and their associated transport in a tokamak plasma. The authors investigate the property of the ion temperature gradient (ITG) or {eta}{sub i}({eta}{sub i} {equivalent_to} {partial_derivative}{ell}nT{sub i}/{partial_derivative}{ell}n n{sub i}) driven drift waves in a tokamak plasma. The emergent semi-global drift wave modes give rise to thermal transport characterized by the Bohm scaling.

  8. 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.

  9. Tokamak Spectroscopy for X-Ray Astronomy

    Science.gov (United States)

    Fournier, Kevin B.; Finkenthal, M.; Pacella, D.; May, M. J.; Soukhanovskii, V.; Mattioli, M.; Leigheb, M.; Rice, J. E.

    2000-01-01

    This paper presents the measured x-ray and Extreme Ultraviolet (XUV) spectra of three astrophysically abundant elements (Fe, Ca and Ne) from three different tokamak plasmas. In every case, each spectrum touches on an issue of atomic physics that is important for simulation codes to be used in the analysis of high spectral resolution data from current and future x-ray telescopes. The utility of the tokamak as a laboratory test bed for astrophysical data is demonstrated. Simple models generated with the HULLAC suite of codes demonstrate how the atomic physics issues studied can affect the interpretation of astrophysical data.

  10. Tokamak Engineering Technology Facility scoping study

    Energy Technology Data Exchange (ETDEWEB)

    Stacey, W.M. Jr.; Abdou, M.A.; Bolta, C.C.

    1976-03-01

    A scoping study for a Tokamak Engineering Technology Facility (TETF) is presented. The TETF is a tokamak with R = 3 m and I/sub p/ = 1.4 MA based on the counterstreaming-ion torus mode of operation. The primary purpose of TETF is to demonstrate fusion technologies for the Experimental Power Reactor (EPR), but it will also serve as an engineering and radiation test facility. TETF has several technological systems (e.g., superconducting toroidal-field coil, tritium fuel cycle, impurity control, first wall) that are prototypical of EPR.

  11. The Spherical Tokamak MEDUSA for Mexico

    Science.gov (United States)

    Ribeiro, C.; Salvador, M.; Gonzalez, J.; Munoz, O.; Tapia, A.; Arredondo, V.; Chavez, R.; Nieto, A.; Gonzalez, J.; Garza, A.; Estrada, I.; Jasso, E.; Acosta, C.; Briones, C.; Cavazos, G.; Martinez, J.; Morones, J.; Almaguer, J.; Fonck, R.

    2011-10-01

    The former spherical tokamak MEDUSA (Madison EDUcation Small Aspect.ratio tokamak, R Mexican Fusion Network. Strong liaison within national and international plasma physics communities is expected. New activities on plasma & engineering modeling are expected to be developed in parallel by using the existing facilities such as a multi-platform computer (Silicon Graphics Altix XE250, 128G RAM, 3.7TB HD, 2.7GHz, quad-core processor), ancillary graph system (NVIDIA Quadro FE 2000/1GB GDDR-5 PCI X16 128, 3.2GHz), and COMSOL Multiphysics-Solid Works programs.

  12. Electron cyclotron emission diagnostics on KSTAR tokamak.

    Science.gov (United States)

    Jeong, S H; Lee, K D; Kogi, Y; Kawahata, K; Nagayama, Y; Mase, A; Kwon, M

    2010-10-01

    A new electron cyclotron emission (ECE) diagnostics system was installed for the Second Korea Superconducting Tokamak Advanced Research (KSTAR) campaign. The new ECE system consists of an ECE collecting optics system, an overmode circular corrugated waveguide system, and 48 channel heterodyne radiometer with the frequency range of 110-162 GHz. During the 2 T operation of the KSTAR tokamak, the electron temperatures as well as its radial profiles at the high field side were measured and sawtooth phenomena were also observed. We also discuss the effect of a window on in situ calibration.

  13. Electron cyclotron emission diagnostics on KSTAR tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, S. H. [Korea Atomic Energy Research Institute, 1045 Daedeokdaero, Daejeon 305-353 (Korea, Republic of); Lee, K. D.; Kwon, M. [National Fusion Research Institute, 113 Gwahangno, Daejeon 305-333 (Korea, Republic of); Kogi, Y. [Fukuoka Institute of Technology, Higashiku, Fukuoka 811-0295 (Japan); Kawahata, K.; Nagayama, Y. [National Institute for Fusion Science, Toki, Gifu 509-5292 (Japan); Mase, A. [KASTEC, Kyushu University, Kasuga, Fukuoka 816-8580 (Japan)

    2010-10-15

    A new electron cyclotron emission (ECE) diagnostics system was installed for the Second Korea Superconducting Tokamak Advanced Research (KSTAR) campaign. The new ECE system consists of an ECE collecting optics system, an overmode circular corrugated waveguide system, and 48 channel heterodyne radiometer with the frequency range of 110-162 GHz. During the 2 T operation of the KSTAR tokamak, the electron temperatures as well as its radial profiles at the high field side were measured and sawtooth phenomena were also observed. We also discuss the effect of a window on in situ calibration.

  14. Tokamak power systems studies, FY 1985

    Energy Technology Data Exchange (ETDEWEB)

    Baker, C.C.; Brooks, J.N.; Ehst, D.A.; Smith, D.L.; Sze, D.K.

    1985-12-01

    The Tokamak Power System Studies (TPSS) at ANL in FY-1985 were devoted to exploring innovative design concepts which have the potential for making substantial improvements in the tokamak as a commercial power reactor. Major objectives of this work included improved reactor economics, improved environmental and safety features, and the exploration of a wide range of reactor plant outputs with emphasis on reduced plant sizes compared to STARFIRE. The activities concentrated on three areas: plasma engineering, impurity control, and blanket/first wall/shield technology. 205 refs., 125 figs., 107 tabs.

  15. 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.

  16. 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

    , the measured spectra agree quantitatively with the synthetic spectra in periods with and without NBI heating. For the discharges investigated, the central velocity distribution of neutral beam ions can be described by classical slowing down. These results will have a major impact on ITER physics exploration......, since CTS is presently the only diagnostic to measure the confined alpha particles produced by the fusion reactions....

  17. Upgrade trigger: Bandwidth strategy proposal

    CERN Document Server

    Fitzpatrick, Conor; Meloni, Simone; Boettcher, Thomas Julian; Whitehead, Mark Peter; Dziurda, Agnieszka; Vesterinen, Mika Anton

    2017-01-01

    This document describes a selection strategy for the upgrade trigger using charm signals as a benchmark. The Upgrade trigger uses a 'Run 2-like' sequence consisting of a first and second stage, in between which the calibration and alignment is performed. The first stage, HLT1, uses an inclusive strategy to select beauty and charm decays, while the second stage uses offline-quality exclusive selections. A novel genetic algorithm-based bandwidth division is performed at the second stage to distribute the output bandwidth among different physics channels, maximising the efficiency for useful physics events. The performance is then studied as a function of the available output bandwidth.

  18. Upgrade trigger: Bandwidth strategy proposal

    CERN Document Server

    Boettcher, Thomas Julian; Meloni, Simone; Whitehead, Mark Peter; Williams, Mark Richard James

    2017-01-01

    This document describes a proposed selection strategy for the upgrade trigger using charm signals as a benchmark. The Upgrade trigger uses a 'Run2-like' sequence consisting of a first and second stage, in between which the calibration and alignment is performed. The first stage, HLT1, uses an inclusive strategy to select beauty and charm, while the second stage uses offline-quality exclusive selections. A novel genetic algorithm-based bandwidth division is performed at the second stage to maximise the output of useful physics events, and a range of possible signal efficiencies are presented as a function of the available bandwidth.

  19. LHCb DAQ network upgrade tests

    CERN Document Server

    Pisani, Flavio

    2013-01-01

    My project concerned the evaluation of new technologies for the DAQ network upgrade of LHCb. The first part consisted in developing and Open Flow-based Clos network. This new technology is very interesting and powerful but, as shown by the results, it still needs further improvements. The second part consisted in testing and benchmarking 40GbE network equipment: Mellanox MT27500, Chelsio T580 and Huawei Cloud Engine 12804. An event-building simulation is currently been performed in order to check the feasibility of the DAQ network upgrade in LS2. The first results are promising.

  20. Advanced tokamak concepts and reactor designs

    NARCIS (Netherlands)

    Oomens, A. A. M.

    2000-01-01

    From a discussion of fusion reactor designs based on today's well-established experience gained in the operation of large tokamaks, it is concluded that such reactors are economically not attractive. The physics involved in the various options for concept improvement is described, some examples

  1. UCLA Tokamak Program Close Out Report.

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, Robert John [UCLA/retired

    2014-02-04

    The results of UCLA experimental fusion program are summarized. Starting with smaller devices like Microtor, Macrotor, CCT and ending the research on the large (5 m) Electric Tokamak. CCT was the most diagnosed device for H-mode like physics and the effects of rotation induced radial fields. ICRF heating was also studied but plasma heating of University Type Tokamaks did not produce useful results due to plasma edge disturbances of the antennae. The Electric Tokamak produced better confinement in the seconds range. However, it presented very good particle confinement due to an "electric particle pinch". This effect prevented us from reaching a quasi steady state. This particle accumulation effect was numerically explained by Shaing's enhanced neoclassical theory. The PI believes that ITER will have a good energy confinement time but deleteriously large particle confinement time and it will disrupt on particle pinching at nominal average densities. The US fusion research program did not study particle transport effects due to its undue focus on the physics of energy confinement time. Energy confinement time is not an issue for energy producing tokamaks. Controlling the ash flow will be very expensive.

  2. INTEGRATED PLASMA CONTROL FOR ADVANCED TOKAMAKS

    Energy Technology Data Exchange (ETDEWEB)

    HUMPHREYS,D.A; FERRON,J.R; JOHNSON,R.D; LEUER,J.A; PENAFLOR,B.G; WALKER,M.L; WELANDER,A.S; KHAYRUTDINOV,R.R; DOKOUKA,V; EDGELL,D.H; FRANSSON,C.M

    2003-10-01

    OAK-B135 Advanced tokamaks (AT) are distinguished from conventional tokamaks by their high degree of shaping, achievement of profiles optimized for high confinement and stability characteristics, and active stabilization of MHD instabilities to attain high values of normalized beta and confinement. These high performance fusion devices thus require accurate regulation of the plasma boundary, internal profiles, pumping, fueling, and heating, as well as simultaneous and well-coordinated MHD control action to stabilize such instabilities as tearing modes and resistive wall modes. Satisfying the simultaneous demands on control accuracy, reliability, and performance for all of these subsystems requires a high degree of integration in both design and operation of the plasma control system in an advanced tokamak. The present work describes the approach, benefits, and progress made in integrated plasma control with application examples drawn from the DIII-D tokamak. The approach includes construction of plasma and system response models, validation of models against operating experiments, design of integrated controllers which operate in concert with one another as well as with supervisory modules, simulation of control action against off-line and actual machine control platforms, and iteration of the design-test loop to optimize performance.

  3. Tokamak startup with electron cyclotron heating

    Energy Technology Data Exchange (ETDEWEB)

    Holly, D J; Prager, S C; Shepard, D A; Sprott, J C

    1980-04-01

    Experiments are described in which the startup voltage in a tokamak is reduced by approx. 60% by the use of a modest amount of electron cyclotron resonance heating power for preionization. A 50% reduction in volt-second requirement and impurity reflux are also observed.

  4. Tokamak Transport Studies Using Perturbation Analysis

    NARCIS (Netherlands)

    Cardozo, N. J. L.; Dehaas, J. C. M.; Hogeweij, G. M. D.; Orourke, J.; Sips, A.C.C.; Tubbing, B. J. D.

    1990-01-01

    Studies of the transport properties of tokamak plasmas using perturbation analysis are discussed. The focus is on experiments with not too large perturbations, such as sawtooth induced heat and density pulse propagation, power modulation and oscillatory gas-puff experiments. The approximations made

  5. ATLAS Detector : Performance and Upgrades

    CERN Document Server

    Oliveira Damazio, Denis; The ATLAS collaboration

    2016-01-01

    Describe the ATLAS detector and summarize most relevant and recent information about the detector performance in 2016 with LHC colliding bunches at sqrt(s)=13 TeV with luminosity above the nominal value. Describe the different upgrade phases previewed for the detector and main activities already ongoing.

  6. 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.

  7. Topology of toroidal helical fields in non-circular cross-sectional tokamaks

    Institute of Scientific and Technical Information of China (English)

    Zha Xue-Jun; Zhu Si-Zheng; Yu Qing-Quan; Wang Yan

    2005-01-01

    The ordinary differential magnetic field line equations are solved numerically; the tokamak magnetic structure is studied on Hefei Tokamak-7 Upgrade (HT-7U) when the equilibrium field with a monotonic q-profile is perturbed by a helical magnetic field. We find that a single mode (m, n) helical perturbation can cause the formation of islands on rational surfaces with q = m/n and q = (m ± 1,±2, ±3,...)/n due to the toroidicity and plasma shape (i.e.elongation and triangularity), while there are many undestroyed magnetic surfaces called Kolmogorov-Arnold-Moser (KAM) barriers on irrational surfaces. The islands on the same rational surface do not have the same size. When the ratio between the perturbing magnetic field (B)r(r) and the toroidal magnetic field amplitude Bφ0 is large enough, the magnetic island chains on different rational surfaces will overlap and chaotic orbits appear in the overlapping area, and the magnetic field becomes stochastic. It is remarkable that the stochastic layer appears first in the plasma edge region.

  8. Experiments with Liquid Metal Walls: Status of the Lithium Tokamak Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Kaita, Robert; Boyle, Dennis; Gray, Timothy; Granstedt, Erik; Hammett, Gregory; Jacobson, Craig M; Jones, Andrew; Kozub, Thomas; Kugel, Henry; Leblanc, Benoit; Logan, Nicholas; Lucia, Matthew; Lundberg, Daniel; Majeski, Richard; Mansfield, Dennis; Menard, Jonathan; Spaleta, Jeffrey; Strickler, Trevor

    2010-02-16

    Liquid metal walls have been proposed to address the first wall challenge for fusion reactors. The Lithium Tokamak Experiment (LTX) at the Princeton Plasma Physics Laboratory (PPPL) is the first magnetic confinement device to have liquid metal plasma-facing components (PFC's) that encloses virtually the entire plasma. In the Current Drive Experiment-Upgrade (CDX-U), a predecessor to LTX at PPPL, the highest improvement in energy confinement ever observed in Ohmically-heated tokamak plasmas was achieved with a toroidal liquid lithium limiter. The LTX extends this liquid lithium PFC by using a conducting conformal shell that almost completely surrounds the plasma. By heating the shell, a lithium coating on the plasma-facing side can be kept liquefied. A consequence of the low-recycling conditions from liquid lithium walls is the need for efficient plasma fueling. For this purpose, a molecular cluster injector is being developed. Future plans include the installation of a neutral beam for core plasma fueling, and also ion temperature measurements using charge-exchange recombination spectroscopy. Low edge recycling is also predicted to reduce temperature gradients that drive drift wave turbulence. Gyrokinetic simulations are in progress to calculate fluctuation levels and transport for LTX plasmas, and new fluctuation diagnostics are under development to test these predictions. __________________________________________________

  9. Concept development and numerical analysis of tokamak heating and current drive

    Energy Technology Data Exchange (ETDEWEB)

    Ju, Myung Hee; Hong, Bong Guen [Korea Atomic Energy Research Institute, Taejon (Korea)

    1998-10-01

    We have done the analytical study on the coupling between the KSTAR plasma and RF antenna necessary for the engineering design of the KSTAR auxiliary heating and current drive system as well as the KSTAR RF antenna. With the code TORIC, the possible parameter ranges of tokamak heating and current drive operation modes using fast wave on the KSTAR are defined and analyzed. The optimized operation scenarios corresponding to the variety of KSTAR fast wave-driven heating and current drive parameters are also developed. With the code RANT3D, the characteristics of the coupling between the KSTAR plasma and RF antenna are analyzed, and the data for the conceptual design of 6 MW KSTAR RF antenna are achieved. Finally the optimum heating and current drive scenarios for the 3 KSTAR operation modes (the baseline reference mode, the upgrade reference mode, the reverse shear mode) using ACCOME and WHIST are developed, and it was shown that they can be realized in KSTAR tokamak with the planned heating and current drive systems. (author). 20 refs., 39 figs., 3 tabs.

  10. Experiments with liquid metal walls: Status of the lithium tokamak experiment

    Energy Technology Data Exchange (ETDEWEB)

    Kaita, Robert, E-mail: kaita@pppl.gov [Princeton Plasma Physics Laboratory, Princeton, NJ (United States); Berzak, Laura; Boyle, Dennis; Gray, Timothy; Granstedt, Erik; Hammett, Gregory; Jacobson, Craig M.; Jones, Andrew; Kozub, Thomas; Kugel, Henry; Leblanc, Benoit; Logan, Nicholas; Lucia, Matthew; Lundberg, Daniel; Majeski, Richard; Mansfield, Dennis; Menard, Jonathan; Spaleta, Jeffrey; Strickler, Trevor; Timberlake, John [Princeton Plasma Physics Laboratory, Princeton, NJ (United States)

    2010-11-15

    Abstarct: Liquid metal walls have been proposed to address the first wall challenge for fusion reactors. The lithium tokamak experiment (LTX) at the Princeton Plasma Physics Laboratory (PPPL) is the first magnetic confinement device to have liquid metal plasma-facing components (PFC's) that encloses virtually the entire plasma. In the current drive experiment-upgrade (CDX-U), a predecessor to LTX at PPPL, the highest improvement in energy confinement ever observed in ohmically heated tokamak plasmas was achieved with a toroidal liquid lithium limiter. The LTX extends this liquid lithium PFC by using a conducting conformal shell that almost completely surrounds the plasma. By heating the shell, a lithium coating on the plasma-facing side can be kept liquefied. A consequence of the low-recycling conditions from liquid lithium walls is the need for efficient plasma fueling. For this purpose, a molecular cluster injector is being developed. Future plans include the installation of a neutral beam for core plasma fueling, and also ion temperature measurements using charge-exchange recombination spectroscopy (CHERS). Low edge recycling is also predicted to reduce temperature gradients that drive drift wave turbulence. Gyrokinetic simulations are in progress to calculate fluctuation levels and transport for LTX plasmas, and new fluctuation diagnostics are under development to test these predictions.

  11. US fusion effort hit by tokamak losses

    Science.gov (United States)

    Gwynne, Peter

    2016-11-01

    Stewart Prager, director of the Princeton Plasma Physics Laboratory (PPPL) in the US, resigned in late September just weeks after a major setback at the lab's National Spherical Torus Experiment Upgrade (NSTX-U).

  12. Characterization of the Tokamak Novillo in cleaning regime; Caracterizacion del Tokamak Novillo en regimen de limpieza

    Energy Technology Data Exchange (ETDEWEB)

    Lopez C, R.; Melendez L, L.; Valencia A, R.; Chavez A, E.; Colunga S, S.; Gaytan G, E

    1992-02-15

    In this work the obtained results of the investigation about the experimental characterization of those low energy pulsed discharges of the Tokamak Novillo are reported. With this it is possible to fix the one operation point but appropriate of the Tokamak to condition the chamber in the smallest possible time for the cleaning discharges regime before beginning the main discharge. The characterization of the cleaning discharges in those Tokamaks is an unique process and characteristic of each device, since the good points of operation are consequence of those particularities of the design of the machine. In the case of the Tokamak Novillo, besides characterizing it a contribution is made to the cleaning discharges regime which consists on the one product of the current peak to peak of plasma by the duration of the discharge Ip{sub t} like reference parameter for the optimization of the operation of the device in the cleaning discharge regime. The maximum value of the parameter I{sub (p)}t, under different work conditions, allowed to find the good operation point to condition the discharges chamber of the Tokamak Novillo in short time and to arrive to a regime in which is not necessary the preionization for the obtaining of the cleaning discharges. (Author)

  13. Banana orbits in elliptic tokamaks with hole currents

    Science.gov (United States)

    Martin, P.; Castro, E.; Puerta, J.

    2015-03-01

    Ware Pinch is a consequence of breaking of up-down symmetry due to the inductive electric field. This symmetry breaking happens, though up-down symmetry for magnetic surface is assumed. In previous work Ware Pinch and banana orbits were studied for tokamak magnetic surface with ellipticity and triangularity, but up-down symmetry. Hole currents appear in large tokamaks and their influence in Ware Pinch and banana orbits are now considered here for tokamaks magnetic surfaces with ellipticity and triangularity.

  14. First Divertor Operation on the HL-2A Tokamak

    Institute of Scientific and Technical Information of China (English)

    YANG Qing-Wei; CAO Zeng; LI Xiao-Dong; MAO Wei-Cheng; ZHOU Cai-Pin; WANG En-Yao; YAN Jian-Cheng; LIU Yong; HL-2A team; DING Xuan-Tong; YAN Long-Wen; XUAN Wei-Min; LIU De-Quan; CHEN Liao-Yuan; SONG Xian-Ming; YUAN Bao-Shan; ZHANG Jin-Hua

    2004-01-01

    @@ HL-2A device is the first divertor tokamak in China. One of its main subjects is to study the features of the divertor plasma. In the last campaign, the first divertor configuration has been achieved and sustained on the HL-2A tokamak. Here we give a brief description about the HL-2A tokamak, diagnostics arrangements, and the equilibrium analysis results on divertor configuration. The main results of divertor experiments are also presented.

  15. 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.

  16. The upgraded Collective Thomson Scattering diagnostics of FTU

    Energy Technology Data Exchange (ETDEWEB)

    Bin, W., E-mail: wbin@ifp.cnr.it [Istituto di Fisica del Plasma – CNR, Milano (Italy); Bruschi, A. [Istituto di Fisica del Plasma – CNR, Milano (Italy); D’Arcangelo, O. [ENEA Unità Tecnica Fusione, C.R. Frascati, Frascati, Roma (Italy); Grosso, G. [Istituto di Fisica del Plasma – CNR, Milano (Italy); Lubiako, L. [Institute of Applied Physics – RAS, Nizhny Novgorod (Russian Federation); Tartari, U.; Figini, L.; Garavaglia, S. [Istituto di Fisica del Plasma – CNR, Milano (Italy); Grossetti, G. [Institute for Applied Materials – KIT, Karlsruhe (Germany); Moro, A. [Istituto di Fisica del Plasma – CNR, Milano (Italy); Orsitto, F.; Centioli, C. [ENEA Unità Tecnica Fusione, C.R. Frascati, Frascati, Roma (Italy); Galperti, C.; Granucci, G.; Mellera, V.; Minelli, D.; Nardone, A.; Simonetto, A. [Istituto di Fisica del Plasma – CNR, Milano (Italy); Vellucci, M. [ENEA Unità Tecnica Fusione, C.R. Frascati, Frascati, Roma (Italy)

    2015-10-15

    Highlights: • The new 140 GHz CTS diagnostics recently installed on the FTU device is presented. • The CTS transmission line is described in detail. • The potential of the new CTS configuration is shown with the aid of simulations. • The radiometric and data acquisition systems are described. • The new code TCSC is described for the first time. - Abstract: The 140 GHz Collective Thomson Scattering (CTS) diagnostics installed on the Frascati Tokamak Upgrade (FTU) has been upgraded. The new system now is ready both to detect the thermal CTS radiation (for the first time with the probe frequency below the 1st harmonic electron cyclotron resonance) and to study the impact of possible parametric decay instability (PDI) processes on the received signals. The EC front-steering antenna and transmission system have been complemented with a receiving line that matches a quasi-optical line feeding the homodyne multi-channel radiometer. The scattering volume can be placed in a wide range of locations by means of fast poloidal and toroidal rotations of the two plasma-facing mirrors that have an up–down symmetry with respect to the equatorial plane of the torus. The data acquisition system has been improved adding a new digitizer, with a bandwidth of 5 GHz and a maximum sampling rate of 12.5 GS/s. The possibility of directly sampling and Fourier transforming the down-converted signals greatly improves the suitability of the new diagnostics to carry out thermal ion temperature measurements and to study the competing PDI processes whenever present.

  17. Rapidly Moving Divertor Plates In A Tokamak

    Energy Technology Data Exchange (ETDEWEB)

    S. Zweben

    2011-05-16

    It may be possible to replace conventional actively cooled tokamak divertor plates with a set of rapidly moving, passively cooled divertor plates on rails. These plates would absorb the plasma heat flux with their thermal inertia for ~10-30 sec, and would then be removed from the vessel for processing. When outside the tokamak, these plates could be cooled, cleaned, recoated, inspected, and then returned to the vessel in an automated loop. This scheme could provide nearoptimal divertor surfaces at all times, and avoid the need to stop machine operation for repair of damaged or eroded plates. We describe various possible divertor plate designs and access geometries, and discuss an initial design for a movable and removable divertor module for NSTX-U.

  18. Magnetic sensor for steady state tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Neyatani, Yuzuru; Mori, Katsuharu; Oguri, Shigeru; Kikuchi, Mitsuru [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment

    1996-06-01

    A new type of magnetic sensor has been developed for the measurement of steady state magnetic fields without DC-drift such as integration circuit. The electromagnetic force induced to the current which leads to the sensor was used for the measurement. For the high frequency component which exceeds higher than the vibration frequency of sensor, pick-up coil was used through the high pass filter. From the results using tokamak discharges, this sensor can measure the magnetic field in the tokamak discharge. During {approx}2 hours measurement, no DC drift was observed. The sensor can respond {approx}10ms of fast change of magnetic field during disruptions. We confirm the extension of measured range to control the current which leads to the sensor. (author).

  19. Boundary Plasma Turbulence Simulations for Tokamaks

    Energy Technology Data Exchange (ETDEWEB)

    Xu, X; Umansky, M; Dudson, B; Snyder, P

    2008-05-15

    The boundary plasma turbulence code BOUT models tokamak boundary-plasma turbulence in a realistic divertor geometry using modified Braginskii equations for plasma vorticity, density (ni), electron and ion temperature (T{sub e}; T{sub i}) and parallel momenta. The BOUT code solves for the plasma fluid equations in a three dimensional (3D) toroidal segment (or a toroidal wedge), including the region somewhat inside the separatrix and extending into the scrape-off layer; the private flux region is also included. In this paper, a description is given of the sophisticated physical models, innovative numerical algorithms, and modern software design used to simulate edge-plasmas in magnetic fusion energy devices. The BOUT code's unique capabilities and functionality are exemplified via simulations of the impact of plasma density on tokamak edge turbulence and blob dynamics.

  20. Module description of TOKAMAK equilibrium code MEUDAS

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, Masaei; Hayashi, Nobuhiko; Matsumoto, Taro; Ozeki, Takahisa [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment

    2002-01-01

    The analysis of an axisymmetric MHD equilibrium serves as a foundation of TOKAMAK researches, such as a design of devices and theoretical research, the analysis of experiment result. For this reason, also in JAERI, an efficient MHD analysis code has been developed from start of TOKAMAK research. The free boundary equilibrium code ''MEUDAS'' which uses both the DCR method (Double-Cyclic-Reduction Method) and a Green's function can specify the pressure and the current distribution arbitrarily, and has been applied to the analysis of a broad physical subject as a code having rapidity and high precision. Also the MHD convergence calculation technique in ''MEUDAS'' has been built into various newly developed codes. This report explains in detail each module in ''MEUDAS'' for performing convergence calculation in solving the MHD equilibrium. (author)

  1. 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.

  2. Self-Organized Stationary States of Tokamaks.

    Science.gov (United States)

    Jardin, S C; Ferraro, N; Krebs, I

    2015-11-20

    We demonstrate that in a 3D resistive magnetohydrodynamic simulation, for some parameters it is possible to form a stationary state in a tokamak where a saturated interchange mode in the center of the discharge drives a near helical flow pattern that acts to nonlinearly sustain the configuration by adjusting the central loop voltage through a dynamo action. This could explain the physical mechanism for maintaining stationary nonsawtoothing "hybrid" discharges, often referred to as "flux pumping."

  3. Resistive interchange instability in reversed shear tokamaks

    Energy Technology Data Exchange (ETDEWEB)

    Furukawa, Masaru; Nakamura, Yuji; Wakatani, Masahiro [Graduate School of Energy Science, Kyoto University, Uji, Kyoto (Japan)

    1999-04-01

    Resistive interchange modes become unstable due to the magnetic shear reversal in tokamaks. In the present paper, the parameter dependences, such as q (safety factor) profile and the magnetic surface shape are clarified for improving the stability, using the local stability criterion. It is shown that a significant reduction of the beta limit is obtained for the JT-60U reversed shear configuration with internal transport barrier, since the local pressure gradient increases. (author)

  4. Internal Kink Instability in Shaped Tokamaks

    Institute of Scientific and Technical Information of China (English)

    王中天; 王龙

    2002-01-01

    A criterion of an ideal internal kink mode is derived for a shaped tokamak configuration in which q-profile is very flat in the core region. A combining criterion is obtained including the necessary criterion of Mercier and the sufficient criterion of Lortz. The new criterion makes progress compared with the necessary criterion of Mercier. In the elongated plasma, a poloidal beta can cause instability, while the triangularity has a stabilizing effect. The result is applicable for DIII-D and SUNIST.

  5. EU Integrated Tokamak Modelling (ITM) Task Force

    Institute of Scientific and Technical Information of China (English)

    A Becoulet

    2007-01-01

    @@ At the end of 2003, the European Fusion Development Agreement (EFDA) structure set-up a long-term European task force (TF) in charge of "co-ordinating the development of a coherent set of validated simulation tools for the purpose of benchmarking on existing tokamak experiments, with the ultimate aim of providing a comprehensive simulation package for ITER plasmas" [http://www.efda-taskforce-itm.org/].

  6. The ALICE pixel detector upgrade

    Science.gov (United States)

    Reidt, F.

    2016-12-01

    The ALICE experiment at the CERN LHC is designed to study the physics of strongly interacting matter, and in particular the properties of the Quark-Gluon Plasma, using proton-proton, proton-nucleus and nucleus-nucleus collisions. The ALICE collaboration is preparing a major upgrade of the experimental apparatus to be installed during the second long LHC shutdown in the years 2019-2020. A key element of the ALICE upgrade is the new, ultra-light, high-resolution Inner Tracking System. With respect to the current detector, the new Inner Tracking System will significantly enhance the pointing resolution, the tracking efficiency at low transverse momenta, and the read-out rate capabilities. This will be obtained by seven concentric detector layers based on a Monolithic Active Pixel Sensor with a pixel pitch of about 30×30 μm2. A key feature of the new Inner Tracking System, which is optimised for high tracking accuracy at low transverse momenta, is the very low mass of the three innermost layers, which feature a material budget of 0.3% X0 per layer. This contribution presents the design goals and layout of the upgraded ALICE Inner Tracking System, summarises the R&D activities focussing on the technical implementation of the main detector components, and the projected detector performance.

  7. Scenarios for the LHC Upgrade

    CERN Document Server

    Scandale, Walter

    2008-01-01

    The projected lifetime of the LHC low-beta quadrupoles, the evolution of the statistical error halving time, and the physics potential all call for an LHC luminosity upgrade by the middle of the coming decade. In the framework of the CARE-HHH network three principal scenarios have been developed for increasing the LHC peak luminosity by more than a factor of 10, to values above 1035 cm−2s−1. All scenarios imply a rebuilding of the high-luminosity interaction regions (IRs) in combination with a consistent change of beam parameters. However, their respective features, bunch structures, IR layouts, merits and challenges, and luminosity variation with β∗ differ substantially. In all scenarios luminosity leveling during a store would be advantageous for the physics experiments. An injector upgrade must complement the upgrade measures in the LHC proper in order to provide the beam intensity and brightness needed as well as to reduce the LHC turnaround time for higher integrated luminosity.

  8. Nonlinear Simulation Studies of Tokamaks and STs

    Energy Technology Data Exchange (ETDEWEB)

    W. Park; J. Breslau; J. Chen; G.Y. Fu; S.C. Jardin; S. Klasky; J. Menard; A. Pletzer; B.C. Stratton; D. Stutman; H.R. Strauss; L.E. Sugiyama

    2003-07-07

    The multilevel physics, massively parallel plasma simulation code, M3D, has been used to study spherical tori (STs) and tokamaks. The magnitude of outboard shift of density profiles relative to electron temperature profiles seen in NSTX [National Spherical Torus Experiment] under strong toroidal flow is explained. Internal reconnection events in ST discharges can be classified depending on the crash mechanism, just as in tokamak discharges; a sawtooth crash, disruption due to stochasticity, or high-beta disruption. Toroidal shear flow can reduce linear growth of internal kink. It has a strong stabilizing effect nonlinearly and causes mode saturation if its profile is maintained, e.g., through a fast momentum source. Normally, however, the flow profile itself flattens during the reconnection process, allowing a complete reconnection to occur. In some cases, the maximum density and pressure spontaneously occur inside the island and cause mode saturation. Gyrokinetic hot particle/MHD hybrid studies of NSTX show the effects of fluid compression on a fast-ion-driven n = 1 mode. MHD studies of recent tokamak experiments with a central current hole indicate that the current clamping is due to sawtooth-like crashes, but with n = 0.

  9. ADX - Advanced Divertor and RF Tokamak Experiment

    Science.gov (United States)

    Greenwald, Martin; Labombard, Brian; Bonoli, Paul; Irby, Jim; Terry, Jim; Wallace, Greg; Vieira, Rui; Whyte, Dennis; Wolfe, Steve; Wukitch, Steve; Marmar, Earl

    2015-11-01

    The Advanced Divertor and RF Tokamak Experiment (ADX) is a design concept for a compact high-field tokamak that would address boundary plasma and plasma-material interaction physics challenges whose solution is critical for the viability of magnetic fusion energy. This device would have two crucial missions. First, it would serve as a Divertor Test Tokamak, developing divertor geometries, materials and operational scenarios that could meet the stringent requirements imposed in a fusion power plant. By operating at high field, ADX would address this problem at a level of power loading and other plasma conditions that are essentially identical to those expected in a future reactor. Secondly, ADX would investigate the physics and engineering of high-field-side launch of RF waves for current drive and heating. Efficient current drive is an essential element for achieving steady-state in a practical, power producing fusion device and high-field launch offers the prospect of higher efficiency, better control of the current profile and survivability of the launching structures. ADX would carry out this research in integrated scenarios that simultaneously demonstrate the required boundary regimes consistent with efficient current drive and core performance.

  10. SOL Width Scaling in the MAST Tokamak

    Science.gov (United States)

    Ahn, Joon-Wook; Counsell, Glenn; Connor, Jack; Kirk, Andrew

    2002-11-01

    Target heat loads are determined in large part by the upstream SOL heat flux width, Δ_h. Considerable effort has been made in the past to develop analytical and empirical scalings for Δh to allow reliable estimates to be made for the next-step device. The development of scalings for a large spherical tokamak (ST) such as MAST is particularly important both for development of the ST concept and for improving the robustness of scalings derived for conventional tokamaks. A first such scaling has been developed in MAST DND plasmas. The scaling was developed by flux-mapping data from the target Langmuir probe arrays to the mid-plane and fitting to key upstream parameters such as P_SOL, bar ne and q_95. In order to minimise the effects of co-linearity, dedicated campaigns were undertaken to explore the widest possible range of each parameter while keeping the remainder as fixed as possible. Initial results indicate a weak inverse dependence on P_SOL and approximately linear dependence on bar n_e. Scalings derived from consideration of theoretical edge transport models and integration with data from conventional devices is under way. The established scaling laws could be used for the extrapolations to the future machine such as Spherical Tokamak Power Plant (STPP). This work is jointly funded by Euratom and UK Department of Trade and Industry. J-W. Ahn would like to recognise the support of a grant from the British Foreign & Commonwealth Office.

  11. Initial DEMO tokamak design configuration studies

    Energy Technology Data Exchange (ETDEWEB)

    Bachmann, Christian, E-mail: christian.bachmann@efda.org [EFDA, Boltzmannstraße 2, 85748 Garching (Germany); Aiello, G. [CEA-Saclay, DEN, DM2S, SEMT, F-91191 Gif-Sur-Yvette (France); Albanese, R.; Ambrosino, R. [ENEA/CREATE, Universita di Napoli Federico II, Naples (Italy); Arbeiter, F. [Karlsruhe Institute of Technology (KIT), Karlsruhe (Germany); Aubert, J. [CEA-Saclay, DEN, DM2S, SEMT, F-91191 Gif-Sur-Yvette (France); Boccaccini, L.; Carloni, D. [Karlsruhe Institute of Technology (KIT), Karlsruhe (Germany); Federici, G. [EFDA, Boltzmannstraße 2, 85748 Garching (Germany); Fischer, U. [Karlsruhe Institute of Technology (KIT), Karlsruhe (Germany); Kovari, M. [CCFE, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Li Puma, A. [CEA-Saclay, DEN, DM2S, SEMT, F-91191 Gif-Sur-Yvette (France); Loving, A. [CCFE, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Maione, I. [Karlsruhe Institute of Technology (KIT), Karlsruhe (Germany); Mattei, M. [ENEA/CREATE, Universita di Napoli Federico II, Naples (Italy); Mazzone, G. [ENEA C.R. Frascati, via E. Fermi 45, 00044 Frascati, Roma (Italy); Meszaros, B. [EFDA, Boltzmannstraße 2, 85748 Garching (Germany); Palermo, I. [Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (CIEMAT), Madrid (Spain); Pereslavtsev, P. [Karlsruhe Institute of Technology (KIT), Karlsruhe (Germany); Riccardo, V. [CCFE, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); and others

    2015-10-15

    Highlights: • A definition of main DEMO requirements. • A description of the DEMO tokamak design configuration. • A description of issues yet to be solved. - Abstract: To prepare the DEMO conceptual design phase a number of physics and engineering assessments were carried out in recent years in the frame of EFDA concluding in an initial design configuration of a DEMO tokamak. This paper gives an insight into the identified engineering requirements and constraints and describes their impact on the selection of the technologies and design principles of the main tokamak components. The EU DEMO program aims at making best use of the technologies developed for ITER (e.g., magnets, vessel, cryostat, and to some degree also the divertor). However, other systems in particular the breeding blanket require design solutions and advanced technologies that will only partially be tested in ITER. The main differences from ITER include the requirement to breed, to extract, to process and to recycle the tritium needed for plasma operation, the two orders of magnitude larger lifetime neutron fluence, the consequent radiation dose levels, which limit remote maintenance options, and the requirement to use low-activation steel for in-vessel components that also must operate at high temperature for efficient energy conversion.

  12. Relativistic runaway electrons in tokamak plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Jaspers, R.E.

    1995-02-03

    Runaway electrons are inherently present in a tokamak, in which an electric field is applied to drive a toroidal current. The experimental work is performed in the tokamak TEXTOR. Here runaway electrons can acquire energies of up to 30 MeV. The runaway electrons are studied by measuring their synchrotron radiation, which is emitted in the infrared wavelength range. The studies presented are unique in the sense that they are the first ones in tokamak research to employ this radiation. Hitherto, studies of runaway electrons revealed information about their loss in the edge of the discharge. The behaviour of confined runaways was still a terra incognita. The measurement of the synchrotron radiation allows a direct observation of the behaviour of runaway electrons in the hot core of the plasma. Information on the energy, the number and the momentum distribution of the runaway electrons is obtained. The production rate of the runaway electrons, their transport and the runaway interaction with plasma waves are studied. (orig./HP).

  13. Nondiffusive plasma transport at tokamak edge

    Science.gov (United States)

    Krasheninnikov, S. I.

    2000-10-01

    Recent findings show that cross field edge plasma transport at tokamak edge does not necessarily obey a simple diffusive law [1], the only type of a transport model applied so far in the macroscopic modeling of edge plasma transport. Cross field edge transport is more likely due to plasma filamentation with a ballistic motion of the filaments towards the first wall. Moreover, it so fast that plasma recycles on the main chamber first wall rather than to flow into divertor as conventional picture of edge plasma fluxes suggests. Crudely speaking particle recycling wise diverted tokamak operates in a limiter regime due to fast anomalous non-diffusive cross field plasma transport. Obviously that this newly found feature of edge plasma anomalous transport can significantly alter a design of any future reactor relevant tokamaks. Here we present a simple model describing the motion of the filaments in the scrape off layer and discuss it implications for experimental observations. [1] M. Umansky, S. I. Krasheninnikov, B. LaBombard, B. Lipschultz, and J. L. Terry, Phys. Plasmas 6 (1999) 2791; M. Umansky, S. I. Krasheninnikov, B. LaBombard and J. L. Terry, Phys. Plasmas 5 (1998) 3373.

  14. Scattering of diffracting beams of electron cyclotron waves by random density fluctuations in inhomogeneous plasmas

    Science.gov (United States)

    Weber, Hannes; Maj, Omar; Poli, Emanuele

    2015-03-01

    The physics and first results of the new WKBeam code for electron cyclotron beams in tokamak plasmas are presented. This code is developed on the basis of a kinetic radiative transfer model which is general enough to account for the effects of diffraction and density fluctuations on the beam. Our preliminary numerical results show a significant broadening of the power deposition profile in ITER due to scattering from random density fluctuations at the plasma edge, while such scattering effects are found to be negligible in medium-size tokamaks like ASDEX upgrade.

  15. H-1 Upgrades (4BW/4BN) (H-1 Upgrades)

    Science.gov (United States)

    2015-12-01

    Nautical Miles R&M - Reliability and Maintainability RM - Reference Model TV-1 - Technical Standards Profile Univ . - Universal H-1 Upgrades December 2015...Speed (kts) 165 165 135 139 139 Payload (Hot Day) (lbs) 3500 lbs 3500 lbs 2500 lbs 6 Wing Stations 4 Universal Under Wing Stations 3429 3429 Weapon...Stations Universal Mounts 6 6 4 4 4 Precision Guided Munitions 16 16 12 16 16 Maneuverability/Agility (G’s) -0.5 to +2.5 -0.5 to +2.5 -0.5 to +2.5 -0.5 to

  16. Thomson scattering system on the TEXTOR tokamak using a multi-pass laser beam configuration

    Energy Technology Data Exchange (ETDEWEB)

    Kantor, M Yu; Donne, A J H; Jaspers, R; Van der Meiden, H J [FOM-Institute for Plasma Physics Rijnhuizen , Association EURATOM-FOM, PO Box 1207, 3430 BE Nieuwegein (Netherlands)], E-mail: m.kantor@fz-juelich.de

    2009-05-15

    The main challenge for the Thomson scattering (TS) diagnostic on the TEXTOR tokamak is the detailed study of fast plasma events at a high spatial resolution and a high repetition rate of the measurements. The diagnostic uses intra-cavity probing of the plasma with a repetitively pulsed ruby laser and a fast CMOS camera as detectors. Since 2004, the TS system on TEXTOR has been gradually and systematically enhanced for the measurements of fast plasma events. For that it has recently been upgraded to obtain a multi-pass configuration. Two spherical mirrors have been installed that force the laser beam to probe the plasma a specified number of times before it is directed back into the laser medium. The diagnostics with the upgraded probing system have achieved the measurement accuracy of 3% for the electron temperature and 1.5% for the electron density at <1 cm spatial resolution and 3 x 10{sup 19} m{sup -3} plasma density and can measure at 5 kHz during an interval up to 8 ms. This makes it possible to detect, amongst others, fine structures of magnetic islands and variations of the edge pedestal in the ELMy limiter H-mode.

  17. Thomson scattering system on the TEXTOR tokamak using a multi-pass laser beam configuration

    Science.gov (United States)

    Kantor, M Yu; Donné, A J H; Jaspers, R; van der Meiden, H J; TEXTOR Team

    2009-05-01

    The main challenge for the Thomson scattering (TS) diagnostic on the TEXTOR tokamak is the detailed study of fast plasma events at a high spatial resolution and a high repetition rate of the measurements. The diagnostic uses intra-cavity probing of the plasma with a repetitively pulsed ruby laser and a fast CMOS camera as detectors. Since 2004, the TS system on TEXTOR has been gradually and systematically enhanced for the measurements of fast plasma events. For that it has recently been upgraded to obtain a multi-pass configuration. Two spherical mirrors have been installed that force the laser beam to probe the plasma a specified number of times before it is directed back into the laser medium. The diagnostics with the upgraded probing system have achieved the measurement accuracy of 3% for the electron temperature and 1.5% for the electron density at <1 cm spatial resolution and 3 × 1019 m-3 plasma density and can measure at 5 kHz during an interval up to 8 ms. This makes it possible to detect, amongst others, fine structures of magnetic islands and variations of the edge pedestal in the ELMy limiter H-mode.

  18. Magnetohydrodynamic Waves and Instabilities in Rotating Tokamak Plasmas

    NARCIS (Netherlands)

    Haverkort, J.W.

    2013-01-01

    One of the most promising ways to achieve controlled nuclear fusion for the commercial production of energy is the tokamak design. In such a device, a hot plasma is confined in a toroidal geometry using magnetic fields. The present generation of tokamaks shows significant plasma rotation, primarily

  19. Soft-X-Ray Tomography Diagnostic at the Rtp Tokamak

    NARCIS (Netherlands)

    Da Cruz, D. F.; Donne, A. J. H.

    1994-01-01

    An 80-channel soft x-ray tomography system has been constructed for diagnosing the RTP (Rijnhuizen Tokamak Project) tokamak plasma. Five pinhole cameras, each with arrays of 16 detectors are distributed more or less homogeneously around a poloidal plasma cross section. The cameras are positioned clo

  20. A simulation study of a controlled tokamak plasma

    Science.gov (United States)

    Fujii, N.; Niwa, Y.

    1980-03-01

    A tokamak circuit theory, including results of numerical simulation studies, is applied to a control system synthesized for a Joule heated tokamak plasma. The treatment is similar to that of Ogata and Ninomiya (1979) except that in this case a quadrupole field coil current is considered coexisting with image induced on a vacuum chamber.

  1. Advanced Accelerator Magnets for Upgrading the LHC

    CERN Document Server

    Rossi, L; de Rijk, G; Todesco, E

    2012-01-01

    The Large Hadron Collider is working at about half its design value, limited by the defective splices of the magnet interconnections. While the full energy will be attained after the splice consolidation in 2014, CERN is preparing a plan for a Luminosity upgrade (High Luminosity LHC) around 2020 and has launched a pre-study for exploring an Energy upgrade (High Energy LHC) around 2030. Both upgrades strongly rely on advanced accelerator magnet technology, requiring dipoles and quadrupoles of accelerator quality and operating fields in the 11-13 T range for the luminosity upgrade and 16-20 T range for the energy upgrade. The paper will review the last ten year of Nb3Sn accelerator magnet R&D and compare it to the needs of the upgrades and will critically assess the results of the Nb3Sn and HTS technology and the planned R&D programs also based on the inputs of first year of LHC operation.

  2. Emission system upgrades for older vehicles

    Energy Technology Data Exchange (ETDEWEB)

    Carlson, R.R.; Finkenbiner, K.; Sommerville, R.J.

    1996-09-01

    Thirteen 1975--1980 model year vehicles were equipped with a set of components to upgrade their emission control systems. Each vehicle was tested before maintenance (as-received), after tune-up and correction of original equipment emission system defects (baseline), and after installation of the emission upgrade system (upgrade). Average emissions of non-methane hydrocarbons (NHMC), carbon monoxide (CO), and nitrogen oxides (NOx) with the emission upgrade system installed were reduced more than 60% from the baseline immediately after upgrade. Six of the vehicles accumulated 48,000 kilometers with the upgrade system. After 48,000 kilometers, average emissions of NMHC and NOx were still reduced approximately 50% compared to the baseline and average emissions of CO were reduced approximately 20%.

  3. Upgrade of the LHCb VELO detector

    Science.gov (United States)

    Williams, Mark

    2017-01-01

    The LHCb experiment is a single-arm forward spectrometer optimised for performing heavy-flavour physics analyses, using proton-proton collisions provided by the LHC machine. A major upgrade of the LHCb experiment will take place prior to the start of Run 3 operations in 2021. The upgraded Vertex Locator (VELO) is an essential component of this upgrade. Its main role is to enable high precision track and vertex reconstruction, with data-driven readout to the software trigger at 40 MHz, in the higher-luminosity environment of Run 3. To achieve this goal, significant improvements are planned with respect to the current detector, including a switch from microstrips to pixels, upgraded electronics, and a new cooling system. I will briefly motiviate the need for an upgrade, describe the main aspects of the VELO upgrade design, and show highlights of recent sensor characterisation studies using the CERN SPS test beam.

  4. Tokamak Plasmas : Measurement of temperature fluctuations and anomalous transport in the SINP tokamak

    Indian Academy of Sciences (India)

    R Kumar; S K Saha

    2000-11-01

    Temperature fluctuations have been measured in the edge region of the SINP tokamak. We find that these fluctuations have a comparatively high level (30–40%) and a broad spectrum. The temperature fluctuations show a quite high coherence with density and potential fluctuations and contribute considerably to the anomalous particle flux.

  5. System assessment of helical reactors in comparison with tokamaks

    Energy Technology Data Exchange (ETDEWEB)

    Yamazaki, K.; Imagawa, S.; Muroga, T.; Sagara, A.; Okamura, S.

    2002-10-01

    A comparative assessment of tokamak and helical reactors has been performed using equivalent physics/engineering model and common costing model. Higher-temperature plasma operation is required in tokamak reactors to increase bootstrap current fraction and to reduce current-drive (CD) power. In helical systems, lower-temperature operation is feasible and desirable to reduce helical ripple transport. The capital cost of helical reactor is rather high, however, the cost of electricity (COE) is almost same as that of tokamak reactor because of smaller re-circulation power (no CD power) and less-frequent blanket replacement (lower neutron wall loading). The standard LHD-type helical reactor with 5% beta value is economically equivalent to the standard tokamak with 3% beta. The COE of lower-aspect ratio helical reactor is on the same level of high-{beta}{sub N} tokamak reactors. (author)

  6. 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.

  7. PF-AR upgrading project

    CERN Document Server

    Kasuga, T

    2002-01-01

    The upgrading project of the dedicated pulse X-ray source PF-AR has been completed by the end of the 2001 fiscal year. Machine commissioning exclusively using the injector linac was successfully accomplished in the beginning of January 2002. After fine tuning of the machine and cleaning of the vacuum system with the beams from the middle of January to the middle of March, routine operation for users has begun in April. The historical details, commissioning and results of the project are reported. (author)

  8. 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; Krzywdzinski, S; Kubantsev, M A; Kubinski, R; Kuchinsky, N; Kuleshov, S; Kulik, Y; Kumar, A; Kunori, S; Kupco, A; Kurca, T; Kvita, J; Kuznetsov, V E; Kwarciany, R; Lager, S; Lahrichi, N; Landsberg, G L; Larwill, M; Laurens, P; Lavigne, B; Lazoflores, J; Le Bihan, A C; Le Meur, G; Lebrun, P; Lee, S W; Lee, W M; Leflat, A; Leggett, C; Lehner, F; Leitner, R; Leonidopoulos, C; Lévêque, J; Lewis, P; Li, J; Li, Q Z; Li, X; Lima, J G R; Lincoln, D; Lindenmeyer, C; Linn, S L; Linnemann, J; Lipaev, V V; Lipton, R; Litmaath, M; Lizarazo, J; Lobo, L; Lobodenko, A; Lokajícek, M; Lounis, A; Love, P; Lü, J; Lubatti, H J; Lucotte, A; Lueking, L; Luo, C; Lynker, M; Lyon, A L; Machado, E; Maciel, A K A; Madaras, R J; Mättig, P; Magass, C; Magerkurth, A; Magnan, A M; Maity, M; Makovec, N; Mal, P K; Malbouisson, H B; Malik, S; Malyshev, V L; Manakov, V; Mao, H S; Maravin, Y; Markley, D; Markus, M; Marshall, T; Martens, M; Martin, M; Martin-Chassard, G; Mattingly, S E K; Matulik, M; Mayorov, A A; McCarthy, R; McCroskey, R; McKenna, M; McMahon, T; Meder, D; Melanson, H L; Melnitchouk, A S; Mendes, A; Mendoza, D; Mendoza, L; Meng, X; Merekov, Y P; Merkin, M; Merritt, K W; Meyer, A; Meyer, J; Michaut, M; Miao, C; Miettinen, H; Mihalcea, D; Mikhailov, V; Miller, D; Mitrevski, J; Mokhov, N; Molina, J; Mondal, N K; Montgomery, H E; Moore, R W; Moulik, T; Muanza, G S; Mostafa, M; Moua, S; Mulders, M; Mundim, L; Mutaf, Y D; Nagaraj, P; Nagy, E; Naimuddin, M; Nang, F; Narain, M; Narasimhan, V S; Narayanan, A; Naumann, N A; Neal, H A; Negret, J P; Nelson, S; Neuenschwander, R T; Neustroev, P; Nöding, C; Nomerotski, A; Novaes, S F; Nozdrin, A; Nunnemann, T; Nurczyk, A; Nurse, E; O'Dell, V; O'Neil, D C; Oguri, V; Olis, D; Oliveira, N; Olivier, B; Olsen, J; Oshima, N; Oshinowo, B O; Oteroy-Garzon, G J; Padley, P; Papageorgiou, K; Parashar, N; Park, J; Park, S K; Parsons, J; Partridge, R; Parua, N; Patwa, A; Pawloski, G; Perea, P M; Pérez, E; Peters, O; Petroff, P; Petteni, M; Phaf, L; Piegaia, R; Pleier, M A; Podesta-Lerma, P L M; Podstavkov, V M; Pogorelov, Y; Pol, M E; Pompos, A; Polosov, P; Pope, B G; Popkov, E; Porokhovoy, S; Prado da Silva, W L; Pritchard, W; Prokhorov, I; Prosper, H B; Protopopescu, S D; Przybycien, M B; Qian, J; Quadt, A; Quinn, B; Ramberg, E; Ramirez-Gomez, R; Rani, K J; Ranjan, K; Rao, M V S; Rapidis, P A; Rapisarda, S; Raskowski, J; Ratoff, P N; Ray, R E; Reay, N W; Rechenmacher, R; Reddy, L V; Regan, T; Renardy, J F; Reucroft, S; Rha, J; Ridel, M; Rijssenbeek, M; Ripp-Baudot, I; Rizatdinova, F K; Robinson, S; Rodrigues, R F; Roco, M T; Rotolo, C; Royon, C; Rubinov, P; Ruchti, R; Rucinski, R; Rud, V I; Rusakovich, N; Russo, P; Sabirov, B; Sajot, G; Sánchez-Hernández, A; Sanders, M P; Santoro, A; Satyanarayana, B; Savage, G; Sawyer, L; Scanlon, T; Schaile, A D; Schamberger, R D; Scheglov, Y; Schellman, H; Schieferdecker, P; Schmitt, C; Schwanenberger, C; Schukin, A A; Schwartzman, A; Schwienhorst, R; Sen-Gupta, S; Severini, H; Shabalina, E; Shamim, M; Shankar, H C; Shary, V; Shchukin, A A; Sheahan, P; Shephard, W D; Shivpuri, R K; Shishkin, A A; Shpakov, D; Shupe, M; Sidwell, R A; Simák, V; Sirotenko, V I; Skow, D; Skubic, P L; Slattery, P F; Smith, D E; Smith, R P; Smolek, K; Snow, G R; Snow, J; Snyder, S; Söldner-Rembold, S; Song, X; Song, Y; Sonnenschein, L; Sopczak, A; Sorin, V; Sosebee, M; Soustruznik, K; Souza, M; Spartana, N; Spurlock, B; Stanton, N R; Stark, J; Steele, J; Stefanik, A; Steinberg, J L; Steinbruck, G; Stevenson, K; Stolin, V; Stone, A; Stoyanova, D A; Strandberg, J; Strang, M A; Strauss, M; Ströhmer, R; Strom, D; Strovink, M; Stutte, L; Sumowidagdo, S; Sznajder, A; Talby, M; Tentindo-Repond, S; Tamburello, P; Taylor, W; Telford, P; Temple, J; Terentyev, N K; Teterin, V; Thomas, E; Thompson, J; Thooris, B; Titov, M; Toback, D; Tokmenin, V V; Tolian, C; Tomoto, M; Tompkins, D; Toole, T; Torborg, J; Touze, F; Towers, S; Trefzger, T; Trincaz-Duvoid, S; Trippe, T G; Tsybychev, D; Tuchming, B; Tully, C; Turcot, A S; Tuts, P M; Utes, M; Uvarov, L; Uvarov, S; Uzunyan, S; Vachon, B; Van den Berg, P J; Van Gemmeren, P; Van Kooten, R; Van Leeuwen, W M; Varelas, N; Varnes, E W; Vartapetian, A H; Vasilyev, I A; Vaupel, M; Vaz, M; Verdier, P; Vertogradov, L S; Verzocchi, M; Vigneault, M; Villeneuve-Séguier, F; Vishwanath, P R; Vlimant, J R; Von Törne, E; Vorobyov, A; Vreeswijk, M; Vu-Anh, T; Vysotsky, V S; Wahl, H D; Walker, R; Wallace, N; Wang, L; Wang, Z M; Warchol, J; Warsinsky, M; Watts, G; Wayne, M; Weber, M; Weerts, H; Wegner, M; Wermes, N; Wetstein, M; White, A; White, V; Whiteson, D; Wicke, D; Wijnen, T A M; Wijngaarden, D A; Wilcer, N; Willutzki, H; Wilson, G W; Wimpenny, S J; Wittlin, J; Wlodek, T; Wobisch, M; Womersley, J; Wood, D R; Wyatt, T R; Wu, Z; Xie, Y; Xu, Q; Xuan, N; Yacoob, S; Yamada, R; Yan, M; Yarema, R J; Yasuda, T; Yatsunenko, Y A; Yen, Y; Yip, K; Yoo, H D; Yoffe, F; Youn, S W; Yu, J; Yurkewicz, A; Zabi, A; Zanabria, M; Zatserklyaniy, A; Zdrazil, M; Zeitnitz, C; Zhang, B; Zhang, D; Zhang, X; Zhao, T; Zhao, Z; Zheng, H; Zhou, B; Zhu, J; Zielinski, M; Zieminska, D; Zieminski, A; Zitoun, R; Zmuda, T; Zutshi, V; Zviagintsev, S; Zverev, E G; Zylberstejn, A

    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.

  9. LHC Status and Upgrade Challenges

    Science.gov (United States)

    Smith, Jeffrey

    2009-11-01

    The Large Hadron Collider has had a trying start-up and a challenging operational future lays ahead. Critical to the machine's performance is controlling a beam of particles whose stored energy is equivalent to 80 kg of TNT. Unavoidable beam losses result in energy deposition throughout the machine and without adequate protection this power would result in quenching of the superconducting magnets. A brief overview of the machine layout and principles of operation will be reviewed including a summary of the September 2008 accident. The current status of the LHC, startup schedule and upgrade options to achieve the target luminosity will be presented.

  10. 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

  11. Upgrading existing evaporators to reduce energy consumption

    Energy Technology Data Exchange (ETDEWEB)

    1977-01-01

    This manual is intended to assist the evaporator engineer who will be performing the technical and economic analyses to determine the most suitable evaporator upgrading technique for his particular plant. Information is included on potentials for upgrading evaporators; correctable operating factors; heat recovery and other improvements in energy use with minor capital investments; upgrading through major capital investments; guidelines for formulating an upgrading program; and new technologies encompassing advanced designs, use of solar and low-grade heat sources, and heat transfer enhancement. A 36 item bibliography is included. (LCL)

  12. 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...

  13. Upgrading of Boundary Dam spillway

    Energy Technology Data Exchange (ETDEWEB)

    McPhail, Gordon; MacMillan, Dave; Smith, Bert [KGS Group, Winnipeg, (Canada); Lacelle, Justin [SaskPower, Regina, (Canada)

    2010-07-01

    An initial dam safety review was performed in 2005 and identified a number of concerns; the most critical were insufficient spillway capacity and deficiencies in the condition of the existing spillways. This paper described the challenges faced by the upgrading operation on the 50 year old Boundary Dam spillway started in 2008. SaskPower retained the KGS Group to increase the design spillway capacity to 1200 m3/s and remedy observed defects. The construction project involved maintaining the reservoir at full supply level while the 20m long spillway chute and stilling basin below were completely replaced. The difficulties came from the need to complete each year's construction such that the spillway could potentially pass spring flood flows. This paper showed that the upgrade measures selected for implementation were developed through close dialogue between the owner and the designer, with valuable input provided by a panel of external experts as well as from contractors participating in the design process.

  14. 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...

  15. On circulating power of steady state tokamaks

    Energy Technology Data Exchange (ETDEWEB)

    Itoh, Kimitaka [National Inst. for Fusion Science, Nagoya (Japan); Itoh, Sanae; Fukuyama, Atsushi; Yagi, Masatoshi

    1996-03-01

    Circulating power for the sustenance and profile control of the steady state tokamak plasmas is discussed. The simultaneous fulfillment of the MHD stability at high beta value, the improved confinement and the stationary equilibrium requires the rotation drive as well as the current drive. In addition to the current drive efficiency, the efficiency for the rotation drive is investigated. The direct rotation drive by the external torque, such as the case of beam injection, is not efficient enough. The mechanism and the magnitude of the spontaneous plasma rotation are studied. (author)

  16. Application of MDSplus on EAST Tokamak

    Institute of Scientific and Technical Information of China (English)

    QU Lianzheng; LUO Jiarong; LI lingling; ZHANG Mingxing; WANG Yong

    2007-01-01

    EAST is a fully superconducting Tokamak in China used for controlled fusion research. MDSplus, a special software package for fusion research, has been used successfully as a central repository for analysed data and PCS (Plasma Control System) data since the debugging experiment in the spring of 2006 . In this paper, the reasons for choosing MDSplus as the analysis database and the way to use it are presented in detail, along with the solution to the problem that part of the MDSplus library does not work in the multithread mode. The experiment showed that the data system based on MDSplus operated stably and it could provide a better performance especially for remote users.

  17. Differential and Integral Models of TOKAMAK

    Directory of Open Access Journals (Sweden)

    Ivo Dolezel

    2004-01-01

    Full Text Available Modeling of 3D electromagnetic phenomena in TOKAMAK with typically distributed main and additional coils is not an easy business. Evaluated must be not only distribution of the magnetic field, but also forces acting in particular coils. Use of differential methods (such as FDM or FEM for this purpose may be complicated because of geometrical incommensurability of particular subregions in the investigated area or problems with the boundary conditions. That is why integral formulation of the problem may sometimes be an advantages. The theoretical analysis is illustrated on an example processed by both methods, whose results are compared and discussed.

  18. Digital controlled pulsed electric system of the ETE tokamak. First report; Sistema eletrico pulsado com controle digital do Tokamak ETE (experimento Tokamak esferico). Primeiro relatorio

    Energy Technology Data Exchange (ETDEWEB)

    Barbosa, Luis Felipe de F.P.W.; Del Bosco, Edson

    1997-12-31

    This reports presents a summary on the thermonuclear fusion and application for energy supply purposes. The tokamak device operation and the magnetic field production systems are described. The ETE tokamak is a small aspect ratio device designed for plasma physics and thermonuclear fusion studies, which presently is under construction at the Laboratorio Associado de Plasma (LAP), Instituto Nacional de Pesquisas Espaciais (INPE) - S.J. dos Campos - S. Paulo. (author) 55 refs., 40 figs.

  19. 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.

  20. 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.

  1. 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.

  2. Electromagnetic simulations of tokamaks and stellarators

    Energy Technology Data Exchange (ETDEWEB)

    Cole, Michael; Mishchenko, Alexey [Max-Planck-Institut fuer Plasmaphysik, EURATOM-Assoziation, Wendelsteinstrasse 1, 17491 Greifswald (Germany)

    2014-07-01

    A practical fusion reactor will require a plasma β of around 5%. In this range Alfvenic effects become important. Since a practical reactor will also produce energetic alpha particles, the interaction between Alfvenic instabilities and fast ions is of particular interest. We have developed a fluid electron, kinetic ion hybrid model that can be used to study this problem. Compared to fully gyrokinetic electromagnetic codes, hybrid codes offer faster running times and greater flexibility, at the cost of reduced completeness. The model has been successfully verified against the worldwide ITPA Toroidal Alfven Eigenmode (TAE) benchmark, and the ideal MHD code CKA for the internal kink mode in a tokamak. Use of the model can now be turned toward cases of practical relevance. Current work focuses on simulating fishbones in a tokamak geometry, which may be of relevance to ITER, and producing the first non-perturbative self-consistent simulations of TAE in a stellarator, which may be of relevance both to Wendelstein 7-X and any future stellarator reactor. Preliminary results of these studies are presented.

  3. Development of atomic beam probe for tokamaks

    Energy Technology Data Exchange (ETDEWEB)

    Berta, M., E-mail: bertam@sze.hu [Széchenyi István University, EURATOM Association, Győr (Hungary); Institute of Plasma Physics AS CR, v.v.i., Prague (Czech Republic); Anda, G.; Aradi, M.; Bencze, A.; Buday, Cs.; Kiss, I.G.; Tulipán, Sz.; Veres, G.; Zoletnik, S. [Wigner – RCP, HAS, EURATOM Association, Budapest (Hungary); Havlícek, J.; Háček, P. [Institute of Plasma Physics AS CR, v.v.i., Prague (Czech Republic); Charles University in Prague, Faculty of Mathematics and Physics (Czech Republic)

    2013-11-15

    Highlights: • ABP is newly developed diagnostic. • Unique measurement method for the determination of plasma edge current variations caused by different transient events such as ELMs. • The design process has been fruitfully supported by the physically motivated computer simulations. • Li-BES system has been modified accordingly to the needs of the ABP. -- Abstract: The concept and development of a new detection method for light alkali ions stemming from diagnostic beams installed on medium size tokamak is described. The method allows us the simultaneous measurement of plasma density fluctuations and fast variations in poloidal magnetic field, therefore one can infer the fast changes in edge plasma current. The concept has been worked out and the whole design process has been done at Wigner RCP. The test detector with appropriate mechanics and electronics is already installed on COMPASS tokamak. General ion trajectory calculation code (ABPIons) has also been developed. Detailed calculations show the possibility of reconstruction of edge plasma current density profile changes with high temporal resolution, and the possibility of density profile reconstruction with better spatial resolution compared to standard Li-BES measurement, this is important for pedestal studies.

  4. Simulating W Impurity Transport in Tokamaks

    Science.gov (United States)

    Younkin, Timothy R.; Green, David L.; Lasa, Ane; Canik, John M.; Wirth, Brian D.

    2016-10-01

    The extreme heat and charged particle flux to plasma facing materials in magnetically confined fusion devices has motivated Tungsten experiments such as the ``W-Ring'' experiment on the DIII-D tokamak to investigate W divertor viability. In this domain, the transport of W impurities from their tile locations to other first-wall tiles is highly relevant to material lifetimes and tokamak operation. Here we present initial results from a simulation of this W transport. Given that sputtered impurities may experience prompt redeposition near the divertor strikepoint, or migrate far from its origin to the midplane, there is a need to track the global, 3-D, impurity redistribution. This is done by directly integrating the 6-D Lorentz equation of motion (plus thermal gradient terms and relevant Monte-Carlo operators) for the impurity ions and neutrals under background plasma parameters determined by the SOLPS edge plasma code. The geometric details of the plasma facing components are represented to a fidelity sufficient to examine the global impurity migration trends with initial work also presented on advanced surface meshing capabilities targeting high fidelity simulation. This work is supported by U.S. DOE Office of Science SciDAC project on plasma-surface interactions under US DOE contract DE-AC05-00OR22725.

  5. Upgradable Software Product Customization by Code Query

    DEFF Research Database (Denmark)

    Vaucouleur, Sebastien

    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...... this constitutes the upgrade problem. We study the upgrade problem in the eld of enterprise systems from a technical point of view, and consider the large spectrum of existing software engineering techniques for customization. We ground our work in an empirical study, that shows that customizations cannot...

  6. Module of lithium divertor for KTM tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Lyublinski, I., E-mail: yublinski@yandex.ru [FSUE ' Red Star' , Moscow (Russian Federation); Vertkov, A.; Evtikhin, V.; Balakirev, V.; Ionov, D.; Zharkov, M. [FSUE ' Red Star' , Moscow (Russian Federation); Tazhibayeva, I. [IAE NNC RK, Kurchatov (Kazakhstan); Mirnov, S. [TRINITI, Troitsk, Moscow Region (Russian Federation); Khomiakov, S.; Mitin, D. [OJSC Dollezhal Institute, Moscow (Russian Federation); Mazzitelli, G. [ENEA RC Frascati (Italy); Agostini, P. [ENEA RC Brasimone (Italy)

    2012-10-15

    Highlights: Black-Right-Pointing-Pointer Problems of PFE degradation, tritium accumulation and plasma pollution can be overcome by the use of liquid lithium-metal with low Z. Black-Right-Pointing-Pointer Capillary-porous system (CPS) - new material in which liquid lithium fill a solid matrix from porous material. Black-Right-Pointing-Pointer Lithium divertor module for KTM tokamak is under development. Black-Right-Pointing-Pointer Lithium filled tungsten felt is offered as the base plasma facing material of divertor. Black-Right-Pointing-Pointer Results of this project addresses to the progress in the field of fusion neutrons source and fusion energy source creation. - Abstract: Activity on projects of ITER and DEMO reactors has shown that solution of problems of divertor target plates and other plasma facing elements (PFEs) based on the solid plasma facing materials cause serious difficulties. Problems of PFE degradation, tritium accumulation and plasma pollution can be overcome by the use of liquid lithium-metal with low Z. Application of lithium will allow to create a self-renewal and MHD stable liquid metal surface of the in-vessel devices possessing practically unlimited service life; to reduce power flux due to intensive re-irradiation on lithium atoms in plasma periphery that will essentially facilitate a problem of heat removal from PFE; to reduce Z{sub eff} of plasma to minimally possible level close to 1; to exclude tritium accumulation, that is provided with absence of dust products and an opportunity of the active control of the tritium contents in liquid lithium. Realization of these advantages is based on use of so-called lithium capillary-porous system (CPS) - new material in which liquid lithium fill a solid matrix from porous material. The progress in development of lithium technology and also activity in lithium experiments in the tokamaks TFTR, T-11M, T-10, FTU, NSTX, HT-7 and stellarator TJ II permits of solving the problems in development of

  7. Overview of recent and current research on the TCV tokamak

    Science.gov (United States)

    S. Codathe TCV Team

    2013-10-01

    Through a diverse research programme, the Tokamak à Configuration Variable (TCV) addresses physics issues and develops tools for ITER and for the longer term goals of nuclear fusion, relying especially on its extreme plasma shaping and electron cyclotron resonance heating (ECRH) launching flexibility and preparing for an ECRH and NBI power upgrade. Localized edge heating was unexpectedly found to decrease the period and relative energy loss of edge localized modes (ELMs). Successful ELM pacing has been demonstrated by following individual ELM detection with an ECRH power cut before turning the power back up to trigger the next ELM, the duration of the cut determining the ELM period. Negative triangularity was also seen to reduce the ELM energy release. H-mode studies have focused on the L-H threshold dependence on the main ion species and on the divertor leg length. Both L- and H-modes have been explored in the snowflake configuration with emphasis on edge measurements, revealing that the heat flux to the strike points on the secondary separatrix increases as the X-points approach each other, well before they coalesce. In L-mode, a systematic scan of the auxiliary power deposition profile, with no effect on confinement, has ruled it out as the cause of confinement degradation. An ECRH power absorption observer based on transmitted stray radiation was validated for eventual polarization control. A new profile control methodology was introduced, relying on real-time modelling to supplement diagnostic information; the RAPTOR current transport code in particular has been employed for joint control of the internal inductance and central temperature. An internal inductance controller using the ohmic transformer has also been demonstrated. Fundamental investigations of neoclassical tearing mode (NTM) seed island formation by sawtooth crashes and of NTM destabilization in the absence of a sawtooth trigger were carried out. Both stabilizing and destabilizing agents

  8. Nonlinear stabilization of tokamak microturbulence by fast ions

    CERN Document Server

    Citrin, J; Garcia, J; Haverkort, J W; Hogeweij, G M D; Jenko, F; Johnson, T; Mantica, P; Pueschel, M J; Told, D; contributors, JET-EFDA

    2013-01-01

    Nonlinear electromagnetic stabilization by suprathermal pressure gradients found in specific regimes is shown to be a key factor in reducing tokamak microturbulence, augmenting significantly the thermal pressure electromagnetic stabilization. Based on nonlinear gyrokinetic simulations investigating a set of ion heat transport experiments on the JET tokamak, described by Mantica et al. [Phys. Rev. Lett. 107 135004 (2011)], this result explains the experimentally observed ion heat flux and stiffness reduction. These findings are expected to improve the extrapolation of advanced tokamak scenarios to reactor relevant regimes.

  9. Ions Measurement at the Edge of HT-7 Tokamak

    Institute of Scientific and Technical Information of China (English)

    Ling Bili; Wang Enyao; Gao wei; Wan Baonian; Li Jiangang

    2005-01-01

    A reliable method of measuring ions and ion temperature in tokamak plasma is necessary, for which an omegatron-like instrument has been developed on the HT-7 tokamak. The basic layout of the omegatron-like instrument is shown in this article. The measurement of working gas ion has been performed in the last experimental campaign on HT-7 tokamak. The relations among ion current, the electron repeller voltage and trap voltage have been investigated. This omegatron-like instrument has also provided the edge-plasma ion temperature.

  10. A systems assessment of the five Starlite tokamak power plants

    Energy Technology Data Exchange (ETDEWEB)

    Bathke, C.G.

    1996-07-01

    The ARIES team has assessed the power-plant attractiveness of the following five tokamak physics regimes: (1) steady state, first stability regime; (2) pulsed, first stability regime; (3) steady state, second stability regime; (4) steady state, reversed shear; and (5) steady state, low aspect ratio. Cost-based systems analysis of these five tokamak physics regimes suggests that an electric power plant based upon a reversed-shear tokamak is significantly more economical than one based on any of the other four physics regimes. Details of this comparative systems analysis are described herein.

  11. Power Deposition on Tokamak Plasma-Facing Components

    CERN Document Server

    Arter, Wayne; Fishpool, Geoff

    2014-01-01

    The SMARDDA software library is used to model plasma interaction with complex engineered surfaces. A simple flux-tube model of power deposition necessitates the following of magnetic fieldlines until they meet geometry taken from a CAD (Computer Aided Design) database. Application is made to 1) models of ITER tokamak limiter geometry and 2) MASTU tokamak divertor designs, illustrating the accuracy and effectiveness of SMARDDA, even in the presence of significant nonaxisymmetric ripple field. SMARDDA's ability to exchange data with CAD databases and its speed of execution also give it the potential for use directly in the design of tokamak plasma facing components.

  12. Open source hard- and software: Using Arduino boards to keep old hardware running

    Energy Technology Data Exchange (ETDEWEB)

    Faugel, Helmut, E-mail: helmut.faugel@ipp.mpg.de [Max-Planck-Institut für Plasmaphysik, EURATOM Association, Garching (Germany); Bobkov, Volodymyr [Max-Planck-Institut für Plasmaphysik, EURATOM Association, Garching (Germany)

    2013-10-15

    The ASDEX Upgrade tokamak went into operation in 1991 with a proposed lifetime of 10 years. Due to major modifications ASDEX Upgrade is still in operation. Infrastructure like data acquisition, workstations, etc. is being modernized, interfaces like RS-232 are vanishing and new interfaces are being introduced. This leads to the necessity to adapt old hardware. Most of the microcontrollers used in the old hardware do not offer any support of the new interfaces and have to be replaced. A simple and efficient way is to replace them with open hardware microcontroller boards like the Arduino. These boards are based on 8-bit RISC microcontrollers and offer a software development environment with a large number of libraries. In this paper the use of Arduino boards for replacing the position unit, the stub tuner interface and its use controlling a direct digital synthesizer (DDS) with phase control capability are shown.

  13. Biological upgrading of coal liquids

    Energy Technology Data Exchange (ETDEWEB)

    1992-01-01

    Culture screening and performance studies were performed with a variety of cultures in removing nitrogen compounds from coal liquid. Two cultures were shown to be effective in removing 17 and 26 percent of the nitrogen in coal liquid as determined by elemental analysis. Experiments will continue in an effort to find additional cultures and isolates able to degrade nitrogen, as well as oxygen and sulfur as heteroatom compounds, from coal liquids. A biological process for upgrading of coal liquids would offer significant advantages, such as operation at ordinary temperature and pressure with better energy efficiency. Of greater importance is the fact that microorganisms do not require an external supply of hydrogen for heteroatom removal, obtaining required hydrogen from water. Furthermore, the biocatalysts are continuously regenerated by growth on the heteroatom compounds. Ring structures are degraded as the heteroatoms are removed. The heteroatoms are in an inocuous form, such as NH[sub 3], SO[sub 4][sup 2[minus

  14. 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...

  15. 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...

  16. LHCb Upgrade: Scintillating Fibre Tracker

    Science.gov (United States)

    Tobin, Mark

    2016-07-01

    The LHCb detector will be upgraded during the Long Shutdown 2 (LS2) of the LHC in order to cope with higher instantaneous luminosities and to read out the data at 40 MHz using a trigger-less read-out system. All front-end electronics will be replaced and several sub-detectors must be redesigned to cope with higher occupancy. The current tracking detectors downstream of the LHCb dipole magnet will be replaced by the Scintillating Fibre (SciFi) Tracker. The SciFi Tracker will use scintillating fibres read out by Silicon Photomultipliers (SiPMs). State-of-the-art multi-channel SiPM arrays are being developed to read out the fibres and a custom ASIC will be used to digitise the signals from the SiPMs. The evolution of the design since the Technical Design Report in 2014 and the latest R & D results are presented.

  17. 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.

  18. Tokamak Plasmas : Internal magnetic field measurement in tokamak plasmas using a Zeeman polarimeter

    Indian Academy of Sciences (India)

    M Jagadeeshwari; J Govindarajan

    2000-11-01

    In a tokamak plasma, the poloidal magnetic field profile closely depends on the current density profile. We can deduce the internal magnetic field from the analysis of circular polarization of the spectral lines emitted by the plasma. The theory of the measurement and a detailed design of the Zeeman polarimeter constructed to measure the poloidal field profile in the ADITYA tokamak are presented. The Fabry-Perot which we have employed in our design, with photodiode arrays followed by lock-in detection of the polarization signal, allows the measurement of the fractional circular polarization. In this system He-II line with wavelength 4686 Å is adopted as the monitoring spectral line. The line emission used in the present measurement is not well localized in the plasma, necessiating the use of a spatial inversion procedure to obtain the local values of the field.

  19. Development of a free boundary Tokamak Equilibrium Solver (TES) for Advanced Study of Tokamak Equilibria

    CERN Document Server

    Jeon, Y M

    2015-01-01

    A free-boundary Tokamak Equilibrium Solver (TES), developed for advanced study of tokamak equilibra, is described with two distinctive features. One is a generalized method to resolve the intrinsic axisymmetric instability, which is encountered after all in equilibrium calculation with a free-boundary condition. The other is an extension to deal with a new divertor geometry such as snowflake or X divertors. For validations, the uniqueness of a solution is confirmed by the independence on variations of computational domain, the mathematical correctness and accuracy of equilibrium profiles are checked by a direct comparison with an analytic equilibrium known as a generalized Solovev equilibrium, and the governing force balance relation is tested by examining the intrinsic axisymmetric instabilities. As a valuable application, a snowflake equilibrium that requires a second order zero of the poloidal magnetic field is discussed in the circumstance of KSTAR coil system.

  20. High-resolution spectroscopy diagnostics for measuring impurity ion temperature and velocity on the COMPASS tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Weinzettl, Vladimir, E-mail: vwei@ipp.cas.cz [Institute of Plasma Physics ASCR, Prague (Czech Republic); Shukla, Gaurav [Institute of Plasma Physics ASCR, Prague (Czech Republic); Department of Applied Physics, Ghent University, Ghent (Belgium); Faculty of Mathematics and Physics, Charles University in Prague, Prague (Czech Republic); Ghosh, Joydeep [Institute for Plasma Research, Bhat, Gandhinagar (India); Melich, Radek; Panek, Radomir [Institute of Plasma Physics ASCR, Prague (Czech Republic); Tomes, Matej; Imrisek, Martin; Naydenkova, Diana [Institute of Plasma Physics ASCR, Prague (Czech Republic); Faculty of Mathematics and Physics, Charles University in Prague, Prague (Czech Republic); Varju, Josef [Institute of Plasma Physics ASCR, Prague (Czech Republic); Pereira, Tiago [Instituto de Plasmas e Fusão Nuclear, Lisboa (Portugal); Instituto Superior Técnico, Universidade de Lisboa, Lisboa (Portugal); Gomes, Rui [Instituto de Plasmas e Fusão Nuclear, Lisboa (Portugal); Abramovic, Ivana; Jaspers, Roger [Eindhoven University of Technology, Eindhoven (Netherlands); Pisarik, Michael [SQS Vlaknova optika a.s., Nova Paka (Czech Republic); Department of Electromagnetic Field, Faculty of Electrical Engineering, Czech Technical University in Prague (Czech Republic); Odstrcil, Tomas [Max-Planck-Institut fur Plasmaphysik, Garching (Germany); Van Oost, Guido [Department of Applied Physics, Ghent University, Ghent (Belgium)

    2015-10-15

    Highlights: • We built a new diagnostic of poloidal plasma rotation on the COMPASS tokamak. • Improvements in throughput via toroidal integration and fiber optimizations shown. • Poloidal rotation and ion temperature measured in L- and H-mode and during RMP. • Design and parameters of a new CXRS diagnostic for COMPASS are introduced. - Abstract: High-resolution spectroscopy is a powerful tool for the measurement of plasma rotation as well as ion temperature using the Doppler shift of the emitted spectral lines and their Doppler broadening, respectively. Both passive and active diagnostic variants for the COMPASS tokamak are introduced. The passive diagnostic focused on the C III lines at about 465 nm is utilized for the observation of the poloidal plasma rotation. The current set-up of the measuring system is described, including the intended high-throughput optics upgrade. Different options to increase the fiber collection area are mentioned, including a flower-like fiber bundle, and the use of micro-lenses or tapered fibers. Recent measurements of poloidal plasma rotation of the order of 0–6 km/s are shown. The design of the new active diagnostic using a deuterium heating beam and based on charge exchange recombination spectroscopy (C VI line at 529 nm) is introduced. The tool will provide both space (0.5–5 cm) and time (10 ms) resolved toroidal plasma rotation and ion temperature profiles. The results of the Simulation of Spectra code used to examine the feasibility of charge exchange measurements on COMPASS are shown and connected with a selection of the spectrometer coupled with the CCD camera.

  1. LONG-PULSE, HIGH-PERFORMANCE DISCHARGES IN THE DIII-D TOKAMAK

    Energy Technology Data Exchange (ETDEWEB)

    T.C. LUCE; M.R. WADE; P.A. POLITZER; S.L. ALLEN; M E. AUSTIN; D.R. BAKER; B.D. BRAY; D.P. BRENNAN; K.H. BURRELL; T.A. CASPER; M.S. CHU; J.D. De BOO; E.J. DOYLE; J.R. FERRON; A.M. GAROFALO; P.GOHIL; I.A. GORELOV; C.M. GREENFIELD; R.J. GROEBNER; W.W. HEIBRINK; C.-L. HSIEH; A.W. HYATT; R.JAYAKUMAR; J.E.KINSEY; R.J. LA HAYE; L.L.LAO; C.J.LASNIER; E.A. LAZARUS; A.W. LEONARD; Y.R.LIN-LIU; J.LOHR; M.A. MAKOWSKI; M.MURAKAMI; C.C.PETTY; R.I. PINSKER; R.PRATER; C.L. RETTIG; T.L. RHODES; B.W. RICE; E.J. STRAIT; T.S. TAYLOR; D.M. THOMAS; A.D. TURNBULL; J.G. WATKINS; W.P.WEST; K.-L. WONG

    2000-10-01

    Significant progress in obtaining high performance discharges for many energy confinement times in the DIII-D tokamak has been realized since the previous IAEA meeting. In relation to previous discharges, normalized performance {approx}10 has been sustained for >5 {tau}{sub E} with q{sub min} >1.5. (The normalized performance is measured by the product {beta}{sub N} H{sub 89} indicating the proximity to the conventional {beta} limits and energy confinement quality, respectively.) These H-mode discharges have an ELMing edge and {beta} {approx}{le} 5%. The limit to increasing {beta} is a resistive wall mode, rather than the tearing modes previously observed. Confinement remains good despite the increase in q. The global parameters were chosen to optimize the potential for fully non-inductive current sustainment at high performance, which is a key program goal for the DIII-D facility in the next two years. Measurement of the current density and loop voltage profiles indicate {approx}75% of the current in the present discharges is sustained non-inductively. The remaining ohmic current is localized near the half radius. The electron cyclotron heating system is being upgraded to replace this remaining current with ECCD. Density and {beta} control, which are essential for operating advanced tokamak discharges, were demonstrated in ELMing H-mode discharges with {beta}{sub N}H{sub 89} {approx} 7 for up to 6.3 s or {approx} 34 {tau}{sub E}. These discharges appear to be in resistive equilibrium with q{sub min} {approx} 1.05, in agreement with the current profile relaxation time of 1.8 s.

  2. Tokamak Plasmas : Observation of floating potential asymmetry in the edge plasma of the SINP tokamak

    Indian Academy of Sciences (India)

    Krishnendu Bhattacharyya; N R Ray

    2000-11-01

    Edge plasma properties in a tokamak is an interesting subject of study from the view point of confinement and stability of tokamak plasma. The edge plasma of SINP-tokamak has been investigated using specially designed Langmuir probes. We have observed a poloidal asymmetry of floating potentials, particularly the top-bottom floating potential differences are quite noticeable, which in turn produces a vertical electric field (v). This v remains throughout the discharge but changes its direction at certain point of time which seems to depend on applied vertical magnetic field v).

  3. Equilibrium reconstruction in the TCA/Br tokamak; Reconstrucao do equilibrio no tokamak TCA/BR

    Energy Technology Data Exchange (ETDEWEB)

    Sa, Wanderley Pires de

    1996-12-31

    The accurate and rapid determination of the Magnetohydrodynamic (MHD) equilibrium configuration in tokamaks is a subject for the magnetic confinement of the plasma. With the knowledge of characteristic plasma MHD equilibrium parameters it is possible to control the plasma position during its formation using feed-back techniques. It is also necessary an on-line analysis between successive discharges to program external parameters for the subsequent discharges. In this work it is investigated the MHD equilibrium configuration reconstruction of the TCA/BR tokamak from external magnetic measurements, using a method that is able to fast determine the main parameters of discharge. The thesis has two parts. Firstly it is presented the development of an equilibrium code that solves de Grad-Shafranov equation for the TCA/BR tokamak geometry. Secondly it is presented the MHD equilibrium reconstruction process from external magnetic field and flux measurements using the Function Parametrization FP method. this method. This method is based on the statistical analysis of a database of simulated equilibrium configurations, with the goal of obtaining a simple relationship between the parameters that characterize the equilibrium and the measurements. The results from FP are compared with conventional methods. (author) 68 refs., 31 figs., 16 tabs.

  4. Toroidicity Dependence of Tokamak Edge Safety Factor and Shear

    Institute of Scientific and Technical Information of China (English)

    SHIBingren

    2002-01-01

    In large tokamak device and reactor designs, the relationship between the toroidal current and the edge safety factor is very important because this will determine the eventual device or reactor size according to MHD stability requirements. In many preliminary

  5. Compact Ignition Tokamak Program: status of FEDC studies

    Energy Technology Data Exchange (ETDEWEB)

    Flanagan, C.A.

    1985-01-01

    Viewgraphs on the Compact Ignition Tokamak Program comprise the report. The technical areas discussed are the mechanical configuration status, magnet analysis, stress analysis, cooling between burns, TF coil joint, and facility/device layout options. (WRF)

  6. BEPCII Injector Linac Upgrade and Beam Instabilities

    Institute of Scientific and Technical Information of China (English)

    WANG Shu-Hong; GENG Zhe-Qiao; PEI Shi-Lun; DENG Bing-Lin; CHEN Zhi-Bi; PEI Guo-Xi; CHI Yun-Long; CHEN Yan-Wei; CAO Jian-She; KONG Xiang-Cheng; ZHAO Feng-Li; HOU Mi; LIU Wei-Bin

    2008-01-01

    The upgrade project of the Beijing Electron Positron Collider (BEPCII) and its injector linac is working well.The linac upgrade aims at a higher injection rate of 50 mA/min into the storage ring,which requires an injected beam with low emittance,low energy spread and high beam orbit and energy stabilities. This goal is finally reached recently by upgrading the linac components and by dealing with rich and practical beam physics,which are described in this study.

  7. NEOCLASSICAL TRANSPORT IN A TOKAMAK WITH ELECTRIC SHEAR

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Neoclassical transport theory for a tokamak in the presence of a large radial electric field with shear is developed using Hamiltonian formalism. Diffusion coefficients are derived in both the plateau and banana regimes where the squeezing factor in coefficients can greatly affect diffusion at the plasma edge. Rotation speeds are calculated in the scrape-off region. They are in good agreement with the measurements on the TdeV tokamak.

  8. Tokamak Start-up under Assistance of RF Waves

    Institute of Scientific and Technical Information of China (English)

    方瑜德

    2004-01-01

    To improve the start-up behavior of tokamak discharges and realize the low loop voltage start-up is required by performance of large scale, full superconductor tokamaks. In recent years, some kinds of RF wave have been used to assist the start-up and some exciting results have been gained. This paper introduce the investigation on both in physical principle and experimental research of the start-up process, in which high frequency RF waves were used to assist it.

  9. Nonlinear lower hybrid modeling in tokamak plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Napoli, F.; Schettini, G. [Università Roma Tre, Dipartimento di Ingegneria, Roma (Italy); Castaldo, C.; Cesario, R. [Associazione EURATOM/ENEA sulla Fusione, Centro Ricerche Frascati (Italy)

    2014-02-12

    We present here new results concerning the nonlinear mechanism underlying the observed spectral broadening produced by parametric instabilities occurring at the edge of tokamak plasmas in present day LHCD (lower hybrid current drive) experiments. Low frequency (LF) ion-sound evanescent modes (quasi-modes) are the main parametric decay channel which drives a nonlinear mode coupling of lower hybrid (LH) waves. The spectrum of the LF fluctuations is calculated here considering the beating of the launched LH wave at the radiofrequency (RF) operating line frequency (pump wave) with the noisy background of the RF power generator. This spectrum is calculated in the frame of the kinetic theory, following a perturbative approach. Numerical solutions of the nonlinear LH wave equation show the evolution of the nonlinear mode coupling in condition of a finite depletion of the pump power. The role of the presence of heavy ions in a Deuterium plasma in mitigating the nonlinear effects is analyzed.

  10. A lithium deposition system for tokamak devices*

    Science.gov (United States)

    Graziul, Christopher; Majeski, Richard; Kaita, Robert; Hoffman, Daniel; Timberlake, John; Card, David

    2002-11-01

    The production of a lithium deposition system using commercially available components is discussed. This system is intended to provide a fresh lithium wall coating between discharges in a tokamak. For this purpose, a film 100-200 Å thick is sufficient to ensure that the plasma interacts solely with the lithium. A test system consisting of a lithium evaporator and a deposition monitor has been designed and constructed to investigate deposition rates and coverage. A Thermionics 3kW e-gun is used to rapidly evaporate small amounts of solid lithium. An Inficon XTM/2 quartz deposition monitor then measures deposition rate at varying distances, positions and angles relative to the e-gun crucible. Initial results from the test system will be presented. *Supported by US DOE contract #DE-AC02-76CH-03073

  11. Safety factor profile control in a tokamak

    CERN Document Server

    Bribiesca Argomedo, Federico; Prieur, Christophe

    2014-01-01

    Control of the Safety Factor Profile in a Tokamak uses Lyapunov techniques to address a challenging problem for which even the simplest physically relevant models are represented by nonlinear, time-dependent, partial differential equations (PDEs). This is because of the  spatiotemporal dynamics of transport phenomena (magnetic flux, heat, densities, etc.) in the anisotropic plasma medium. Robustness considerations are ubiquitous in the analysis and control design since direct measurements on the magnetic flux are impossible (its estimation relies on virtual sensors) and large uncertainties remain in the coupling between the plasma particles and the radio-frequency waves (distributed inputs). The Brief begins with a presentation of the reference dynamical model and continues by developing a Lyapunov function for the discretized system (in a polytopic linear-parameter-varying formulation). The limitations of this finite-dimensional approach motivate new developments in the infinite-dimensional framework. The t...

  12. Dissipative nonlinear structures in tokamak plasmas

    Directory of Open Access Journals (Sweden)

    K. A. Razumova

    2001-01-01

    Full Text Available A lot of different kinds of instabilities may be developed in high temperature plasma located in a strong toroidal magnetic field (tokamak plasma. Nonlinear effects in the instability development result in plasma self-organization. Such plasma has a geometrically complicated configuration, consisting of the magnetic surfaces imbedded into each other and split into islands with various characteristic numbers of helical twisting. The self-consistency of the processes means that the transport coefficients in plasma do not depend just on the local parameters, being a function of the whole plasma configuration and of the forces affecting it. By disrupting the bonds between separate magnetic surfaces filled with islands, one can produce zones of reduced transport in the plasma, i.e. “internal thermal barriers”, allowing one essentially to increase the plasma temperature and density.

  13. Sliding Mode Control of a Tokamak Transformer

    Energy Technology Data Exchange (ETDEWEB)

    Romero, J. A.; Coda, S.; Felici, F.; Moret, J. M.; Paley, J.; Sevillano, G.; Garrido, I.; Le, H. B.

    2012-06-08

    A novel inductive control system for a tokamak transformer is described. The system uses the flux change provided by the transformer primary coil to control the electric current and the internal inductance of the secondary plasma circuit load. The internal inductance control is used to regulate the slow flux penetration in the highly conductive plasma due to the skin effect, providing first-order control over the shape of the plasma current density profile. Inferred loop voltages at specific locations inside the plasma are included in a state feedback structure to improve controller performance. Experimental tests have shown that the plasma internal inductance can be controlled inductively for a whole pulse starting just 30ms after plasma breakdown. The details of the control system design are presented, including the transformer model, observer algorithms and controller design. (Author) 67 refs.

  14. MHD stability limits in the TCV Tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Reimerdes, H. [Ecole Polytechnique Federale de Lausanne, Centre de Recherches en Physique des Plasmas (CRPP), CH-1015 Lausanne (Switzerland)

    2001-07-01

    Magnetohydrodynamic (MHD) instabilities can limit the performance and degrade the confinement of tokamak plasmas. The Tokamak a Configuration Variable (TCV), unique for its capability to produce a variety of poloidal plasma shapes, has been used to analyse various instabilities and compare their behaviour with theoretical predictions. These instabilities are perturbations of the magnetic field, which usually extend to the plasma edge where they can be detected with magnetic pick-up coils as magnetic fluctuations. A spatially dense set of magnetic probes, installed inside the TCV vacuum vessel, allows for a fast observation of these fluctuations. The structure and temporal evolution of coherent modes is extracted using several numerical methods. In addition to the setup of the magnetic diagnostic and the implementation of analysis methods, the subject matter of this thesis focuses on four instabilities, which impose local and global stability limits. All of these instabilities are relevant for the operation of a fusion reactor and a profound understanding of their behaviour is required in order to optimise the performance of such a reactor. Sawteeth, which are central relaxation oscillations common to most standard tokamak scenarios, have a significant effect on central plasma parameters. In TCV, systematic scans of the plasma shape have revealed a strong dependence of their behaviour on elongation {kappa} and triangularity {delta}, with high {kappa}, and low {delta} leading to shorter sawteeth with smaller crashes. This shape dependence is increased by applying central electron cyclotron heating. The response to additional heating power is determined by the role of ideal or resistive MHD in triggering the sawtooth crash. For plasma shapes where additional heating and consequently, a faster increase of the central pressure shortens the sawteeth, the low experimental limit of the pressure gradient within the q = 1 surface is consistent with ideal MHD predictions. The

  15. Vertically stabilized elongated cross-section tokamak

    Science.gov (United States)

    Sheffield, George V.

    1977-01-01

    This invention provides a vertically stabilized, non-circular (minor) cross-section, toroidal plasma column characterized by an external separatrix. To this end, a specific poloidal coil means is added outside a toroidal plasma column containing an endless plasma current in a tokamak to produce a rectangular cross-section plasma column along the equilibrium axis of the plasma column. By elongating the spacing between the poloidal coil means the plasma cross-section is vertically elongated, while maintaining vertical stability, efficiently to increase the poloidal flux in linear proportion to the plasma cross-section height to achieve a much greater plasma volume than could be achieved with the heretofore known round cross-section plasma columns. Also, vertical stability is enhanced over an elliptical cross-section plasma column, and poloidal magnetic divertors are achieved.

  16. Upgrades to MINERVA control software

    Science.gov (United States)

    Wilson, Maurice; Eastman, Jason D.

    2017-01-01

    The MINiature Exoplanet Radial Velocity Array (MINERVA) is an array of four robotic telescopes located on Mt. Hopkins in Arizona that will find and characterize rocky planets around our nearest stars. We discuss the latest upgrades to the MINERVA robotic control software. Previously, our robotic control software was only capable of taking radial velocities or photometry for the entire night, but not both. We have recently increased the speed and ease of transitioning between photometry and radial velocity (RV) observations. We can now arbitrarily assign a subset of the telescopes to either photometric or spectroscopic observations. This capability enables us to monitor stellar activity while measuring the star’s RV, gather photometry on one star while continuing our RV survey of other targets and provide education and public outreach opportunities where others can observe with one or more telescopes while we continue using the remaining telescopes for research. This material is based upon work supported by the National Science Foundation Graduate Research Fellowship Program under Grant No. 1144152.

  17. Upgrade of the CMS Tracker

    CERN Document Server

    Klein, Katja

    2013-01-01

    The performance of the Tracker of the CMS experiment, comprising of a pixel and a strip detector, has so far been excellent, as reflected in the wealth of beautiful physics results from CMS. However, 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. \\\\ In the extended end-of-year shutdown 2016/17 the pixel detector will be exchanged. The new device is designed for an instantaneous luminosity of $2\\cdot 10^{34}$\\,cm$^{-2}$s$^{-1}$ and an integrated luminosity of 500\\,fb$^{-1}$. The number of layers will be increased from three to four in the barrel part and from two to three in the end caps, thus providing four-hit coverage over the full pseudorapidity range. A smaller beampipe allows the reduction of the radius of the innermost layer, improving the tracking performance. Further improvements include a new readout chip, reduction of material, and the installation of more effi...

  18. The upgrade of the LHCb Vertex Locator

    CERN Document Server

    Bird, T

    2014-01-01

    The LHCb experiment is set for a significant upgrade, which will be ready for Run~3 of the LHC in 2020. This upgrade will allow LHCb to run at a significantly higher instantaneous luminosity and collect an integrated luminosity of $50\\,\\text{fb}^{-1}$ by the end of Run~4. In this process the Vertex locator (VELO) detector will be upgraded to a pixel-based silicon detector. The upgraded VELO will improve upon the current detector by being closer to the beam and having lower material modules with microchannel cooling and a thinner RF-foil. Simulations have shown that it will maintain its excellent performance, even after the radiation damage caused by collecting an integrated luminosity of $50\\,\\text{fb}^{-1}$.

  19. Physics benchmarks of the VELO upgrade

    CERN Document Server

    Eklund, Lars

    2017-01-01

    The LHCb Experiment at the LHC is successfully performing precision measurements primarily in the area of flavour physics. The collaboration is preparing an upgrade that will start taking data in 2021 with a trigger-less readout at five times the current luminosity. The vertex locator has been crucial in the success of the experiment and will continue to be so for the upgrade. It will be replaced by a hybrid pixel detector and this paper discusses the performance benchmarks of the upgraded detector. Despite the challenging experimental environment, the vertex locator will maintain or improve upon its benchmark figures compared to the current detector. Finally the long term plans for LHCb, beyond those of the upgrade currently in preparation, are discussed.

  20. System and process for upgrading hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Bingham, Dennis N.; Klingler, Kerry M.; Smith, Joseph D.; Turner, Terry D.; Wilding, Bruce M.

    2015-08-25

    In one embodiment, a system for upgrading a hydrocarbon material may include a black wax upgrade subsystem and a molten salt gasification (MSG) subsystem. The black wax upgrade subsystem and the MSG subsystem may be located within a common pressure boundary, such as within a pressure vessel. Gaseous materials produced by the MSG subsystem may be used in the process carried out within the black wax upgrade subsystem. For example, hydrogen may pass through a gaseous transfer interface to interact with black wax feed material to hydrogenate such material during a cracking process. In one embodiment, the gaseous transfer interface may include one or more openings in a tube or conduit which is carrying the black wax material. A pressure differential may control the flow of hydrogen within the tube or conduit. Related methods are also disclosed.

  1. Recovery Act. Tapoco project. Cheoah upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Tran, Paul [Alcoa Inc., Alcoa Center, PA (United States)

    2013-10-02

    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.

  2. Technology to Upgrade Magneto-Materials

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    @@ CAS scientists have developed a new surface-coating technology to upgrade the product quality of China's permanent magnet materials. The success is appraised by an evaluation penal of the CAS Shenyang Branch in northeastern China' s Liaoning Province.

  3. Lower Hybrid System upgrade on Tore Supra

    Science.gov (United States)

    Beaumont, B.; Beunas, A.; Bibet, P.; Kazarian, F.

    2003-12-01

    An upgrade of the heating systems is in progress on Tore Supra. It is focused on the manufacturing of a new coupler, using the PAM concept as foreseen for ITER launcher, and the upgrade of the existing transmitter by replacing the 16 existing 500 kW, 210 s klystrons with new 750 kW, 1000s klystrons. Main features of the launcher and klystron are presented.

  4. Readout scheme of the upgraded ALICE TPC

    CERN Document Server

    Appelshaeuser, Harald; Ivanov, Marian; Lippmann, Christian; Wiechula, Jens

    2016-01-01

    In this document, we present the updated readout scheme for the ALICE TPC Upgrade. Two major design changes are implemented with respect to the concept that was presented in the TPC Upgrade Technical Design Report: – The SAMPA front-end ASIC will be used in direct readout mode. – The ADC sampling frequency will be reduced from 10 to 5 MHz. The main results from simulations and a description of the new readout scheme is outlined.

  5. MHD stability limits in the TCV Tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Reimerdes, H. [Ecole Polytechnique Federale de Lausanne, Centre de Recherches en Physique des Plasmas (CRPP), CH-1015 Lausanne (Switzerland)

    2001-07-01

    Magnetohydrodynamic (MHD) instabilities can limit the performance and degrade the confinement of tokamak plasmas. The Tokamak a Configuration Variable (TCV), unique for its capability to produce a variety of poloidal plasma shapes, has been used to analyse various instabilities and compare their behaviour with theoretical predictions. These instabilities are perturbations of the magnetic field, which usually extend to the plasma edge where they can be detected with magnetic pick-up coils as magnetic fluctuations. A spatially dense set of magnetic probes, installed inside the TCV vacuum vessel, allows for a fast observation of these fluctuations. The structure and temporal evolution of coherent modes is extracted using several numerical methods. In addition to the setup of the magnetic diagnostic and the implementation of analysis methods, the subject matter of this thesis focuses on four instabilities, which impose local and global stability limits. All of these instabilities are relevant for the operation of a fusion reactor and a profound understanding of their behaviour is required in order to optimise the performance of such a reactor. Sawteeth, which are central relaxation oscillations common to most standard tokamak scenarios, have a significant effect on central plasma parameters. In TCV, systematic scans of the plasma shape have revealed a strong dependence of their behaviour on elongation {kappa} and triangularity {delta}, with high {kappa}, and low {delta} leading to shorter sawteeth with smaller crashes. This shape dependence is increased by applying central electron cyclotron heating. The response to additional heating power is determined by the role of ideal or resistive MHD in triggering the sawtooth crash. For plasma shapes where additional heating and consequently, a faster increase of the central pressure shortens the sawteeth, the low experimental limit of the pressure gradient within the q = 1 surface is consistent with ideal MHD predictions. The

  6. 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.

  7. Trajectory planning of tokamak flexible in-vessel inspection robot

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Hesheng [Department of Automation, Shanghai Jiao Tong University, 200240 Shanghai (China); Key Laboratory of System Control and Information Processing, Ministry of Education of China, 200240 Shanghai (China); Chen, Weidong, E-mail: wdchen@sjtu.edu.cn [Department of Automation, Shanghai Jiao Tong University, 200240 Shanghai (China); Key Laboratory of System Control and Information Processing, Ministry of Education of China, 200240 Shanghai (China); Lai, Yinping; He, Tao [Department of Automation, Shanghai Jiao Tong University, 200240 Shanghai (China); Key Laboratory of System Control and Information Processing, Ministry of Education of China, 200240 Shanghai (China)

    2015-10-15

    Highlights: • A tokamak flexible in-vessel inspection robot is designed. • Two trajectory planning methods are used to ensure the full coverage of the first wall scanning. • The method is tested on a simulated platform of EAST with the flexible in-vessel inspection robot. • Experimental results show the effectiveness of the proposed algorithm. - Abstract: Tokamak flexible in-vessel inspection robot is mainly designed to carry a camera for close observation of the first wall of the vacuum vessel, which is essential for the maintenance of the future tokamak reactor without breaking the working condition of the vacuum vessel. A tokamak flexible in-vessel inspection robot is designed. In order to improve efficiency of the remote maintenance, it is necessary to design a corresponding trajectory planning algorithm to complete the automatic full coverage scanning of the complex tokamak cavity. Two different trajectory planning methods, RS (rough scanning) and FS (fine scanning), according to different demands of the task, are used to ensure the full coverage of the first wall scanning. To quickly locate the damage position, the first trajectory planning method is targeted for quick and wide-ranging scan of the tokamak D-shaped section, and the second one is for careful observation. Furthermore, both of the two different trajectory planning methods can ensure the full coverage of the first wall scanning with an optimal end posture. The method is tested on a simulated platform of EAST (Experimental Advanced Superconducting Tokamak) with the flexible in-vessel inspection robot, and the results show the effectiveness of the proposed algorithm.

  8. Modification to poloidal charge exchange recombination spectroscopy measurement in JT-60U tokamak

    Institute of Scientific and Technical Information of China (English)

    Ding Bo-Jiang; Sakamoto Yoshiteru; Miura Yukitoshi

    2007-01-01

    With consideration of the effects of the atomic process and the sight line direction on the charge exchange recombination spectroscopy (CXRS), a code used to modify the poloidal CXRS measurement on Tokamak-60 Upgrade (JT-60U) in Japan Atomic Energy Research Institute is developed, offering an effective tool to modify the measurement and analyse experimental results further. The results show that the poloidal velocity of ion is overestimated but the ion temperature is underestimated by the poloidal CXRS measurement, and they also indicate that the effect of observation angle on rotation velocity is a dominant one in a core region (r/a< 0.65), whereas in an edge region where the sight line is nearly normal to the neutral beam, the observation angle effect is very small. The difference between the modified velocity and the neoclassical velocity is not larger than the error in measurement. The difference inside the internal transport barrier (ITB) region is 2-3 times larger than that outside the ITB region, and it increases when the effect of excited components in neutral beam is taken into account. The radial electric field profile is affected greatly by the poloidal rotation term, which possibly indicates the correlation between the poloidal rotation and the transport barrier formation.

  9. Progress on the Implementation of a Neutral Beam for the Lithium Tokamak eXperiment-Beta

    Science.gov (United States)

    Merino, Enrique; Kozub, Thomas; Boyle, Dennis; Majeski, Richard; Kaita, Robert; Smirnov, Artem; Catalano, Ryan

    2016-10-01

    In the Lithium Tokamak eXperiment (LTX), good performance discharges have been achieved with reduced-recycling lithium walls. Two hydrogen neutral beams (NB) have been loaned to the LTX project by Tri-Alpha Energy, Inc. To further improve plasma parameters, one of these neutral beams is being installed as part of an upgrade to LTX (LTX-Beta). Current ohmic input power in LTX is less than 100 kW. The NB will provide core plasma fueling with up to 700 kW of injected power. Requirements for accommodating the NB include the addition of injection and beam-dump ports on the vessel, and their designs have been finalized. Progress has also been made on the NB power supplies, including the preparation of a new room to accommodate them. A description of these activities and the status of other improvements to LTX for LTX-Beta will be presented. Work supported by US DOE contracts DE-AC02- 09CH11466 and DE-AC05- 00OR22725.

  10. Development of 3D ferromagnetic model of tokamak core with strong toroidal asymmetry

    DEFF Research Database (Denmark)

    Markovič, Tomáš; Gryaznevich, Mikhail; Ďuran, Ivan;

    2015-01-01

    Fully 3D model of strongly asymmetric tokamak core, based on boundary integral method approach (i.e. characterization of ferromagnet by its surface) is presented. The model is benchmarked on measurements on tokamak GOLEM, as well as compared to 2D axisymmetric core equivalent for this tokamak...

  11. Basic Physics of Tokamak Transport Final Technical Report.

    Energy Technology Data Exchange (ETDEWEB)

    Sen, Amiya K.

    2014-05-12

    The goal of this grant has been to study the basic physics of various sources of anomalous transport in tokamaks. Anomalous transport in tokamaks continues to be one of the major problems in magnetic fusion research. As a tokamak is not a physics device by design, direct experimental observation and identification of the instabilities responsible for transport, as well as physics studies of the transport in tokamaks, have been difficult and of limited value. It is noted that direct experimental observation, identification and physics study of microinstabilities including ITG, ETG, and trapped electron/ion modes in tokamaks has been very difficult and nearly impossible. The primary reasons are co-existence of many instabilities, their broadband fluctuation spectra, lack of flexibility for parameter scans and absence of good local diagnostics. This has motivated us to study the suspected tokamak instabilities and their transport consequences in a simpler, steady state Columbia Linear Machine (CLM) with collisionless plasma and the flexibility of wide parameter variations. Earlier work as part of this grant was focused on both ITG turbulence, widely believed to be a primary source of ion thermal transport in tokamaks, and the effects of isotope scaling on transport levels. Prior work from our research team has produced and definitively identified both the slab and toroidal branches of this instability and determined the physics criteria for their existence. All the experimentally observed linear physics corroborate well with theoretical predictions. However, one of the large areas of research dealt with turbulent transport results that indicate some significant differences between our experimental results and most theoretical predictions. Latter years of this proposal were focused on anomalous electron transport with a special focus on ETG. There are several advanced tokamak scenarios with internal transport barriers (ITB), when the ion transport is reduced to

  12. Zeeman Spectroscopy of Tokamak Edge Plasmas

    Science.gov (United States)

    Hey, J. D.; Chu, C. C.; Mertens, Ph.

    2002-12-01

    Zeeman spectroscopy is a valuable tool both for diagnostic purposes, and for more fundamental studies of atomic and molecular processes in the boundary region of magnetically confined fusion plasmas (B ≃ 1 to 10 T). The method works well when the Zeeman (Paschen-Back) effect plays an important, or dominant, rôle in relation to other broadening mechanisms (Doppler, Stark, resonant excitation transfer) in determining the spectral line shape. For impurity species identification and temperature determination, Zeeman spectroscopy has advantages over charge-exchange recombination spectroscopy from highly excited radiator states, since spectral features practically unique to the species under investigation are analysed. It also provides useful information on probable mechanisms of line production (e.g. sputtering mechanisms, electron impact-induced dissociative excitation from molecules in the edge plasma), and on the temperature evolution of lower charge states in the process of convection inwards or diffusion outwards from the hotter plasma interior. Where different physical processes are responsible for different sections of the line profile — especially in the case of hydrogen isotopes — Zeeman spectroscopy can provide a set of characteristic temperatures for each section. The method is introduced in both passive and active spectroscopy, and general principles of the Zeeman effect are discussed with special reference to régimes of interest for the tokamak. Relevant physical processes (sputtering mechanisms, electron impact-induced dissociative excitation from molecules in the edge plasma, and ion-atom collisional heating mechanisms) are illustrated by sample spectra.

  13. Aspects of Tokamak toroidal magnet protection

    Energy Technology Data Exchange (ETDEWEB)

    Green, R.W.; Kazimi, M.S.

    1979-07-01

    Simple but conservative geometric models are used to estimate the potential for damage to a Tokamak reactor inner wall and blanket due to a toroidal magnet field collapse. The only potential hazard found to exist is due to the MHD pressure rise in a lithium blanket. A survey is made of proposed protection methods for superconducting toroidal magnets. It is found that the two general classifications of protection methods are thermal and electrical. Computer programs were developed which allow the toroidal magnet set to be modeled as a set of circular filaments. A simple thermal model of the conductor was used which allows heat transfer to the magnet structure and which includes the effect of temperature dependent properties. To be effective in large magnets an electrical protection system should remove at least 50% of the stored energy in the protection circuit assuming that all of the superconductor in the circuit quenches when the circuit is activated. A protection system design procedure based on this criterion was developed.

  14. Tokamak blanket design study, final report

    Energy Technology Data Exchange (ETDEWEB)

    1980-08-01

    A cylindrical module concept was developed, analyzed, and incorporated in a tokamak blanket system that includes piping systems, vacuum boundary sealing, and support structures. The design is based on the use of state-of-the-art structural materials (20% cold-worked type 316 stainless steel), lithium as the breeding material, and pressurized helium as the coolant. The module design consists of nested concentric cylinders (with an outer diameter of 10 cm) and features direct wall cooling by helium flowing between the outer (first-wall) cylinder and the inner (lithium-containing) cylinder. Each cylinder can withstand full coolant pressure, thus enhancing reliability. Results show that stainless steel is a viable material for a first wall subjected to a neutron wall loading of 4 MW/m/sup 2/ and a particle heat flux of 1 MW/m/sup 2/. Lifetime analysis shows that the first-wall design meets the goal of operating at 20-min cycles with 95% duty for 100,000 cycles. To reduce system complexity, a larger 20-cm-diam module also was analyzed for incorporation in the blanket assembly. Reliability assessment indicates that it may be possible to double the module in size from 10 to 20 cm in diameter. With a modest increase in coolant pumping power, a blanket assembly comprising 20-cm-diam modules can still achieve 100,000 operating cycles - equivalent to a 3.6-year design lifetime - with only one or two helium coolant leaks into the plasma.

  15. Prospects for pilot plants based on the tokamak, spherical tokamak and stellarator

    Science.gov (United States)

    Menard, J. E.; Bromberg, L.; Brown, T.; Burgess, T.; Dix, D.; El-Guebaly, L.; Gerrity, T.; Goldston, R. J.; Hawryluk, R. J.; Kastner, R.; Kessel, C.; Malang, S.; Minervini, J.; Neilson, G. H.; Neumeyer, C. L.; Prager, S.; Sawan, M.; Sheffield, J.; Sternlieb, A.; Waganer, L.; Whyte, D.; Zarnstorff, M.

    2011-10-01

    A potentially attractive next-step towards fusion commercialization is a pilot plant, i.e. a device ultimately capable of small net electricity production in as compact a facility as possible and in a configuration scalable to a full-size power plant. A key capability for a pilot-plant programme is the production of high neutron fluence enabling fusion nuclear science and technology (FNST) research. It is found that for physics and technology assumptions between those assumed for ITER and nth-of-a-kind fusion power plant, it is possible to provide FNST-relevant neutron wall loading in pilot devices. Thus, it may be possible to utilize a single facility to perform FNST research utilizing reactor-relevant plasma, blanket, coil and auxiliary systems and maintenance schemes while also targeting net electricity production. In this paper three configurations for a pilot plant are considered: the advanced tokamak, spherical tokamak and compact stellarator. A range of configuration issues is considered including: radial build and blanket design, magnet systems, maintenance schemes, tritium consumption and self-sufficiency, physics scenarios and a brief assessment of research needs for the configurations.

  16. Modelling and control of a tokamak plasma; Modelisation et commande d`un plasma de tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Bremond, S.

    1995-10-18

    Vertically elongated tokamak plasmas, while attractive as regards Lawson criteria, are intrinsically instable. It is found that the open-loop instability dynamics is characterised by the relative value of two dimensionless parameters: the coefficient of inductive coupling between the vessel and the coils, and the coil damping efficiency on the plasma displacement relative to that of the vessel. Applications to Tore Supra -where the instability is due to the iron core attraction- and DIII-D are given. A counter-effect of the vessel, which temporarily reverses the effect of coil control on the plasma displacement, is seen when the inductive coupling is higher than the damping ratio. Precise control of the plasma boundary is necessary if plasma-wall interaction and/or coupling to heating antennas are to be monitored. A positional drift, of a few mm/s, which had been observed in the Tore Supra tokamak, is explained and corrected. A linear plasma shape response model is then derived from magnetohydrodynamic equilibrium calculation, and proved to be in good agreement with experimental data. An optimal control law is derived, which minimizes an integral quadratic criteria on tracking errors and energy expenditure. This scheme avoids compensating coil currents, and could render local plasma shaping more precise. (authors). 123 refs., 77 figs., 6 tabs., 4 annexes.

  17. TSC (Tokamak Simulation Code) disruption scenarios and CIT (Compact Ignition Tokamak) vacuum vessel force evolution

    Energy Technology Data Exchange (ETDEWEB)

    Sayer, R.O.; Peng, Y.K.M.; Strickler, D.J.; Jardin, S.C.

    1990-01-01

    The Tokamak Simulation Code and the TWIR postprocessor code have been used to develop credible plasma disruption scenarios for the Compact Ignition Tokamak (CIT) in order to predict the evolution of forces on CIT conducting structures and to provide results required for detailed structural design analysis. The extreme values of net radial and vertical vacuum vessel (VV) forces were found to be F{sub R}={minus}12.0 MN/rad and F{sub Z}={minus}3.0 MN/rad, respectively, for the CIT 2.1-m, 11-MA design. Net VV force evolution was found to be altered significantly by two mechanisms not noted previously. The first, due to poloidal VV currents arising from increased plasma paramagnetism during thermal quench, reduces the magnitude of the extreme F{sub R} by 15-50{percent} and modifies the distribution of forces substantially. The second effect is that slower plasma current decay rates give more severe net vertical VV loads because the current decay occurs when the plasma has moved farther from midplane than is the case for faster decay rates. 7 refs., 9 figs., 1 tab.

  18. Reducing CO2 emission from bitumen upgrading

    Energy Technology Data Exchange (ETDEWEB)

    Gordon, John

    2011-07-15

    The treatment of sand oil can result in significant CO2 emission. Ceramatec Inc. has developed a technology to reduce the emission of CO2 during the upgrading of feedstocks bearing heteroatoms. This technology can be applied to kerogen derived oil (shale oil) and heavy oil as well as to bitumen from oil sands. Metallic sodium is used as the reducing and heteroatom scavenging agent. Hydrogen, methane or other hydrocarbons may be used to cap radicals formed in the process. But using methane can lead to lower material and capital costs, greater product yield, and lower CO2 emission. During the upgrading process, the aromatic constituents remain in the product, after treatment with sodium and removal of sulphur, nitrogen and metals. Aromatic saturation is not required with sodium, so less hydrogen is needed which leads to reduced CO2 emission. The reason is that CO2 is emitted in the steam methane reforming (SMR) process where hydrogen is produced. An example is introduced to demonstrate the reduction of CO2 emission from hydrogen production. Another advantage of the sodium/methane upgrading process is the incorporation of methane into the fuel. In addition, the total acid number, TAN, becomes negligible in the sodium upgrading processes. Ceramatec has also developed a process for the recovery of sodium from the sodium salts generated in the sodium/methane upgrading process.

  19. Deposit of thin films for Tokamaks conditioning; Deposito de peliculas delgadas para acondicionar Tokamaks

    Energy Technology Data Exchange (ETDEWEB)

    Valencia A, R

    2006-07-01

    As a main objective of this work, we present some experimental results obtained from studying the process of extracting those impurities created by the interaction plasma with its vessel wall in the case of Novillo tokamak. Likewise, we describe the main cleaning and conditioning techniques applied to it, fundamentally that of glow discharge cleaning at a low electron temperature (<10 eV), both in noble and reactive gases, as well as the conditioning by thin film deposits of hydrogen rich amorphous carbon (carbonization) leading to a reduction in the plasma resistivity from 8.99 x 10{sup -6} to 4.5 x 10{sup -6} {omega}-m, thus taking the Z{sub ef} value from 3.46 to 2.07 which considerably improved the operational parameters of the machine. With a view to justifying the fact that controlled nuclear fusion is a feasible alternative for the energy demand that humanity will face in the future, we review in Chapter 1 some fundamentals of the energy production by nuclear fusion reactions while, in Chapter 2, we examine two relevant plasma wall interaction processes. Our experimental array used to produce both cleaning and intense plasma discharges is described in Chapter 3 along with the associated diagnostics equipment. Chapter 4 contains a description of the vessel conditioning techniques followed in the process. Finally, we report our results in Chapter 5 while, in Chapter 6, some conclusions and remarks are presented. It is widely known that tokamak impurities are generated mainly by the plasma-wall interaction, particularly in the presence of high potentials between the plasma sheath and the limiter or wall. Given that impurities affect most adversely the plasma behaviour, understanding and controlling the impurity extraction mechanisms is crucial for optimizing the cleaning and wall conditioning discharge processes. Our study of one impurity extraction mechanism for both low and high Z in Novillo tokamak was carried out though mass spectrometry, optical emission

  20. The Dynamic Mutation Characteristics of Thermonuclear Reaction in Tokamak

    Directory of Open Access Journals (Sweden)

    Jing Li

    2014-01-01

    Full Text Available The stability and bifurcations of multiple limit cycles for the physical model of thermonuclear reaction in Tokamak are investigated in this paper. The one-dimensional Ginzburg-Landau type perturbed diffusion equations for the density of the plasma and the radial electric field near the plasma edge in Tokamak are established. First, the equations are transformed to the average equations with the method of multiple scales and the average equations turn to be a Z2-symmetric perturbed polynomial Hamiltonian system of degree 5. Then, with the bifurcations theory and method of detection function, the qualitative behavior of the unperturbed system and the number of the limit cycles of the perturbed system for certain groups of parameter are analyzed. At last, the stability of the limit cycles is studied and the physical meaning of Tokamak equations under these parameter groups is given.

  1. A control approach for plasma density in tokamak machines

    Energy Technology Data Exchange (ETDEWEB)

    Boncagni, Luca, E-mail: luca.boncagni@enea.it [EURATOM – ENEA Fusion Association, Frascati Research Center, Division of Fusion Physics, Rome, Frascati (Italy); Pucci, Daniele; Piesco, F.; Zarfati, Emanuele [Dipartimento di Ingegneria Informatica, Automatica e Gestionale ' ' Antonio Ruberti' ' , Sapienza Università di Roma (Italy); Mazzitelli, G. [EURATOM – ENEA Fusion Association, Frascati Research Center, Division of Fusion Physics, Rome, Frascati (Italy); Monaco, S. [Dipartimento di Ingegneria Informatica, Automatica e Gestionale ' ' Antonio Ruberti' ' , Sapienza Università di Roma (Italy)

    2013-10-15

    Highlights: •We show a control approach for line plasma density in tokamak. •We show a control approach for pressure in a tokamak chamber. •We show experimental results using one valve. -- Abstract: In tokamak machines, chamber pre-fill is crucial to attain plasma breakdown, while plasma density control is instrumental for several tasks such as machine protection and achievement of desired plasma performances. This paper sets the principles of a new control strategy for attaining both chamber pre-fill and plasma density regulation. Assuming that the actuation mean is a piezoelectric valve driven by a varying voltage, the proposed control laws ensure convergence to reference values of chamber pressure during pre-fill, and of plasma density during plasma discharge. Experimental results at FTU are presented to discuss weaknesses and strengths of the proposed control strategy. The whole system has been implemented by using the MARTe framework [1].

  2. Tokamak dust particle size and surface area measurement

    Energy Technology Data Exchange (ETDEWEB)

    Carmack, W.J.; Smolik, G.R.; Anderl, R.A.; Pawelko, R.J.; Hembree, P.B.

    1998-07-01

    The INEEL has analyzed a variety of dust samples from experimental tokamaks: General Atomics` DII-D, Massachusetts Institute of Technology`s Alcator CMOD, and Princeton`s TFTR. These dust samples were collected and analyzed because of the importance of dust to safety. The dust may contain tritium, be activated, be chemically toxic, and chemically reactive. The INEEL has carried out numerous characterization procedures on the samples yielding information useful both to tokamak designers and to safety researchers. Two different methods were used for particle characterization: optical microscopy (count based) and laser based volumetric diffraction (mass based). Surface area of the dust samples was measured using Brunauer, Emmett, and Teller, BET, a gas adsorption technique. The purpose of this paper is to present the correlation between the particle size measurements and the surface area measurements for tokamak dust.

  3. Hybrid Method for Tokamak MHD Equilibrium Configuration Reconstruction

    Institute of Scientific and Technical Information of China (English)

    HE Hong-Da; DONG Jia-Qi; ZHANG Jin-Hua; JIANG Hai-Bin

    2007-01-01

    A hybrid method for tokamak MHD equilibrium configuration reconstruction is proposed and employed in the modified EFIT code. This method uses the free boundary tokamak equilibrium configuration reconstruction algorithm with one boundary point fixed. The results show that the position of the fixed point has explicit effects on the reconstructed divertor configurations. In particular, the separatrix of the reconstructed divertor configuration precisely passes the required position when the hybrid method is used in the reconstruction. The profiles of plasma parameters such as pressure and safety factor for reconstructed HL-2A tokamak configurations with the hybrid and the free boundary methods are compared. The possibility for applications of the method to swing the separatrix strike point on the divertor target plate is discussed.

  4. Thes - Website for Thermal Shields Upgrade Management

    CERN Document Server

    Micula, Adina

    2013-01-01

    There are a total of 1695 thermal shields (TS) in the interconnections between the superconducting magnets. During LHC Long Shutdown 1 (LS1) all of these TS are being upgraded with a new fixation design. This procedure involves the transport of all the TS from LHC to a workshop on the surface where they are being modified and the subsequent transport of the upgraded TS back to the tunnel where they are laid on the cryostats and await the closure of the interconnection. These operations have to be carefully coordinated in order to ensure that there are always enough modified TS to satisfy the demand in the tunnel and respect the time constraint imposed by the schedule of LS1. As part of my summer project, I developed a database driven website whose aim is to enable the TS upgrade monitoring.

  5. Microbial biocatalyst developments to upgrade fossil fuels.

    Science.gov (United States)

    Kilbane, John J

    2006-06-01

    Steady increases in the average sulfur content of petroleum and stricter environmental regulations concerning the sulfur content have promoted studies of bioprocessing to upgrade fossil fuels. Bioprocesses can potentially provide a solution to the need for improved and expanded fuel upgrading worldwide, because bioprocesses for fuel upgrading do not require hydrogen and produce far less carbon dioxide than thermochemical processes. Recent advances have demonstrated that biodesulfurization is capable of removing sulfur from hydrotreated diesel to yield a product with an ultra-low sulfur concentration that meets current environmental regulations. However, the technology has not yet progressed beyond laboratory-scale testing, as more efficient biocatalysts are needed. Genetic studies to obtain improved biocatalysts for the selective removal of sulfur and nitrogen from petroleum provide the focus of current research efforts.

  6. Tracking triggers for the upgraded DOe detector

    Energy Technology Data Exchange (ETDEWEB)

    Glenn, S. [California Univ., Davis (United States); Bloom, P. [California Univ., Davis (United States); Mani, S. [California Univ., Davis (United States); Pellett, D. [California Univ., Davis (United States); Costa, J. [CBPF/LAFEX, Rio de Janeiro (Brazil); Moreira, L. [CBPF/LAFEX, Rio de Janeiro (Brazil); Baumbaugh, A. [Fermi National Accelerator Laboratory, Batavia, IL (United States); Blazey, G. [Fermi National Accelerator Laboratory, Batavia, IL (United States); Borcherding, F. [Fermi National Accelerator Laboratory, Batavia, IL (United States); Johnson, M. [Fermi National Accelerator Laboratory, Batavia, IL (United States); Wilcox, J. [Northeastern University, Boston, MA (United States)

    1995-06-01

    The high luminosity environment of the upgraded Tevatron will require not only the upgrade of various DOe subdetectors, but the trigger system as well. With respect to the present system, the upgraded trigger system must operate faster and provide a higher degree of background rejection while extending the physics acceptance beyond that of the current system. This will be accomplished in part by incorporating the scintillating fiber tracker and the preshower detector into the Level 1 trigger. Track logic, implemented in commercial FPGAs, will be used to identify tracks in the scintillating fiber tracker with P{sub T}>1.5 GeV/c and electron candidates in the preshower detector. Integration of the trigger logic and readout electronics permits the identification of all tracks in a few hundred nanoseconds. Here, preliminary designs for the readout and trigger electronics are presented along with simulation results for trigger efficiencies and rejection factors. (orig.).

  7. 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.

  8. The upstream tracker for the LHCb upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Steinkamp, Olaf, E-mail: olafs@physik.uzh.ch

    2016-09-21

    The LHCb collaboration is planning a comprehensive upgrade of the experiment for the long shutdown of the LHC in 2019/20. As part of this upgrade, the tracking station in front of the LHCb dipole magnet will be replaced by a new planar four-layer silicon micro-strip detector with 40 MHz readout and silicon sensors with finer granularity and improved radiation hardness. Key design aspects of this new Upstream Tracker are described and a brief overview of the status of the project is given.

  9. Take control of upgrading to Snow Leopard

    CERN Document Server

    Kissell, Joe

    2009-01-01

    Installing a major new version of Mac OS X should be exciting and fun, but without proper guidance you may find it nerve-wracking or even risk losing valuable files. Fortunately, many thousands of people have upgraded Mac OS X calmly and successfully with Joe Kissell's previous best-selling Take Control of Upgrading... titles. Joe's friendly, expert steps-developed over innumerable test installations-help you to avoid trouble, understand what's going on when you install Snow Leopard, and easily recover from problem

  10. CMS DT Upgrade The Sector Collector Relocation

    CERN Document Server

    Navarro Tobar, Alvaro

    2015-01-01

    The Sector Collector relocation is the first stage of the upgrade program for the Drift Tubes subdetector of the CMS experiment. It was accomplished during Long Shutdown 2013-2014, and consisted in the relocation of the second-level trigger and readout electronics from the experimental to the service cavern, relieving the environmental constraints and improving accessibility for maintenance and upgrade. Extending the electrical links would degrade reliability, so the information is converted to optical with a custom system capable of dealing with the DC-unbalanced data. Initially, present electronics are used, so optical-to-copper conversion has also been installed.

  11. Design and Analysis of the Thermal Shield of EAST Tokamak

    Institute of Scientific and Technical Information of China (English)

    XIE Han; LIAO Ziying

    2008-01-01

    EAST (Experimental Advanced Superconducting Tokamak) is a tokamak with superconducting toroidal and poloidal magnets operated at 4.5 K. In order to reduce the thermal load applied on the surfaces of all cryogenically cooled components and keep the heat load of the cryogenic system at a minimum, a continuous radiation shield system located between the magnet system and warm components is adopted. The main loads to which the thermal shield system is subjected are gravity, seismic, electromagnetic and thermal gradients. This study employed NASTRAN and ANSYS finite element codes to analyze the stress under a spectrum of loading conditions and combinations, providing a theoretical basis for an optimization design of the structure.

  12. A CONCEPT FOR NEXT STEP ADVANCED TOKAMAK FUSION DEVICE

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A concept is introduced for initiating the design study of a special class of tokamak,which has a magnetic confinement configuration intermediate between contemporary advanced tokamak and the recently established spherical torus (ST,also well known by the name "spherical tokamak").The leading design parameter in the present proposal is a dimensionless geometrical parameter, the machine aspect ratio A=R0/a0=2.0,where the parameters a0 and R0 denote,respectively,the plasma (equatorial) minor radius and the plasma major radius.The aim of this choice is to technologically and experimentally go beyond the aspect ratio frontier (R0/a0≈2.5) of present day tokamaks and enter a broad unexplored domain existing on the (a0,R0) parameter space in current international tokamak database,between the data region already moderately well covered by the advanced conventional tokamaks and the data region planned to be covered by STs.Plasma minor radius a0 has been chosen to be the second basic design parameter, and consequently,the plasma major radius R0 is regarded as a dependent design parameter.In the present concept,a nominal plasma minor radius a0=1.2m is adopted to be the principal design value,and smaller values of a0 can be used for auxiliary design purposes,to establish extensive database linkage with existing tokamaks.Plasma minor radius can also be adjusted by mechanical and/or electromagnetic means to smaller values during experiments,for making suitable data linkages to existing machines with higher aspect ratios and smaller plasma minor radii.The basic design parameters proposed enable the adaptation of several confinement techniques recently developed by STs,and thereby a specially arranged central-bore region inside the envisioned tokamak torus,with retrieved space in the direction of plasma minor radius,will be available for technological adjustments and maneuverings to facilitate implementation of engineering instrumentation and real time high

  13. Measurement of Current Profile in a Tokamak Through AC Modulation

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The plasma current is modulated with an alternating current (ac) component in a frequency range of 90 Hz~900 Hz in the plateau discharge phase in the CT-6B tokamak. A plasma electric conductivity profile in a form of (1 - r2/a2)α with a parameter α, which is fitted with the experimental data, can be determined. The effects of magnetic shear in a tokamak field configuration on the current penetration are taken into account in the numerical simulation. The measurement method and obtained results are discussed.

  14. Adaptive grid finite element model of the tokamak scrapeoff layer

    Energy Technology Data Exchange (ETDEWEB)

    Kuprat, A.P.; Glasser, A.H. [Los Alamos National Lab., NM (United States)

    1995-07-01

    The authors discuss unstructured grids for application to transport in the tokamak edge SOL. They have developed a new metric with which to judge element elongation and resolution requirements. Using this method, the authors apply a standard moving finite element technique to advance the SOL equations while inserting/deleting dynamically nodes that violate an elongation criterion. In a tokamak plasma, this method achieves a more uniform accuracy, and results in highly stretched triangular finite elements, except near separatrix X-point where transport is more isotropic.

  15. TIBER: Tokamak Ignition/Burn Experimental Research. Final design report

    Energy Technology Data Exchange (ETDEWEB)

    Henning, C.D.; Logan, B.G.; Barr, W.L.; Bulmer, R.H.; Doggett, J.N.; Johnson, B.M.; Lee, J.D.; Hoard, R.W.; Miller, J.R.; Slack, D.S.

    1985-11-01

    The Tokamak Ignition/Burn Experimental Research (TIBER) device is the smallest superconductivity tokamak designed to date. In the design plasma shaping is used to achieve a high plasma beta. Neutron shielding is minimized to achieve the desired small device size, but the superconducting magnets must be shielded sufficiently to reduce the neutron heat load and the gamma-ray dose to various components of the device. Specifications of the plasma-shaping coil, the shielding, coaling, requirements, and heating modes are given. 61 refs., 92 figs., 30 tabs. (WRF)

  16. Simulation of EAST vertical displacement events by tokamak simulation code

    Science.gov (United States)

    Qiu, Qinglai; Xiao, Bingjia; Guo, Yong; Liu, Lei; Xing, Zhe; Humphreys, D. A.

    2016-10-01

    Vertical instability is a potentially serious hazard for elongated plasma. In this paper, the tokamak simulation code (TSC) is used to simulate vertical displacement events (VDE) on the experimental advanced superconducting tokamak (EAST). Key parameters from simulations, including plasma current, plasma shape and position, flux contours and magnetic measurements match experimental data well. The growth rates simulated by TSC are in good agreement with TokSys results. In addition to modeling the free drift, an EAST fast vertical control model enables TSC to simulate the course of VDE recovery. The trajectories of the plasma current center and control currents on internal coils (IC) fit experimental data well.

  17. Computer simulation of transport driven current in tokamaks

    Energy Technology Data Exchange (ETDEWEB)

    Nunan, W.J.; Dawson, J.M. (University of California at Los Angeles, Department of Physics, 405 Hilgard Avenue, Los Angeles, California 90024-1547 (United States))

    1994-09-19

    We have investigated transport driven current in tokamaks via 2+1/2 dimensional, electromagnetic, particle-in-cell simulations. These have demonstrated a steady increase of toroidal current in centrally fueled plasmas. Neoclassical theory predicts that the bootstrap current vanishes at large aspect ratio, but we see equal or greater current growth in straight cylindrical plasmas. These results indicate that a centrally fueled and heated tokamak may sustain its toroidal current, even without the seed current'' which the neoclassical bootstrap theory requires.

  18. Resistive demountable toroidal-field coils for tokamak reactors

    Energy Technology Data Exchange (ETDEWEB)

    Jassby, D.L.; Jacobsen, R.A.; Kalnavarns, J.; Masson, L.S.; Sekot, J.P.

    1981-07-01

    Readily demountable TF (toroidal-field) coils allow complete access to the internal components of a tokamak reactor for maintenance of replacement. The requirement of readily demountable joints dictates the use of water-cooled resistive coils, which have a host of decisive advantages over superconducting coils. Previous papers have shown that resistive TF coils for tokamak reactors can operate in the steady state with acceptable power dissipation (typically, 175 to 300 MW). This paper summarizes results of parametric studies of size optimization of rectangular TF coils and of a finite-element stress analysis, and examines several candidate methods of implementing demountable joints for rectangular coils constructed of plate segments.

  19. Fusion neutron diagnostics on ITER tokamak

    Science.gov (United States)

    Bertalot, L.; Barnsley, R.; Direz, M. F.; Drevon, J. M.; Encheva, A.; Jakhar, S.; Kashchuk, Y.; Patel, K. M.; Arumugam, A. P.; Udintsev, V.; Walker, C.; Walsh, M.

    2012-04-01

    ITER is an experimental nuclear reactor, aiming to demonstrate the feasibility of nuclear fusion realization in order to use it as a new source of energy. ITER is a plasma device (tokamak type) which will be equipped with a set of plasma diagnostic tools to satisfy three key requirements: machine protection, plasma control and physics studies by measuring about 100 different parameters. ITER diagnostic equipment is integrated in several ports at upper, equatorial and divertor levels as well internally in many vacuum vessel locations. The Diagnostic Systems will be procured from ITER Members (Japan, Russia, India, United States, Japan, Korea and European Union) mainly with the supporting structures in the ports. The various diagnostics will be challenged by high nuclear radiation and electromagnetic fields as well by severe environmental conditions (ultra high vacuum, high thermal loads). Several neutron systems with different sensitivities are foreseen to measure ITER expected neutron emission from 1014 up to almost 1021 n/s. The measurement of total neutron emissivity is performed by means of Neutron Flux Monitors (NFM) installed in diagnostic ports and by Divertor Neutron Flux Monitors (DNFM) plus MicroFission Chambers (MFC) located inside the vacuum vessel. The neutron emission profile is measured with radial and vertical neutron cameras. Spectroscopy is accomplished with spectrometers looking particularly at 2.5 and 14 MeV neutron energy. Neutron Activation System (NAS), with irradiation ends inside the vacuum vessel, provide neutron yield data. A calibration strategy of the neutron diagnostics has been developed foreseeing in situ and cross calibration campaigns. An overview of ITER neutron diagnostic systems and of the associated challenging engineering and integration issues will be reported.

  20. Magnetic flux reconstruction methods for shaped tokamaks

    Energy Technology Data Exchange (ETDEWEB)

    Tsui, Chi-Wa

    1993-12-01

    The use of a variational method permits the Grad-Shafranov (GS) equation to be solved by reducing the problem of solving the 2D non-linear partial differential equation to the problem of minimizing a function of several variables. This high speed algorithm approximately solves the GS equation given a parameterization of the plasma boundary and the current profile (p` and FF` functions). The author treats the current profile parameters as unknowns. The goal is to reconstruct the internal magnetic flux surfaces of a tokamak plasma and the toroidal current density profile from the external magnetic measurements. This is a classic problem of inverse equilibrium determination. The current profile parameters can be evaluated by several different matching procedures. Matching of magnetic flux and field at the probe locations using the Biot-Savart law and magnetic Green`s function provides a robust method of magnetic reconstruction. The matching of poloidal magnetic field on the plasma surface provides a unique method of identifying the plasma current profile. However, the power of this method is greatly compromised by the experimental errors of the magnetic signals. The Casing Principle provides a very fast way to evaluate the plasma contribution to the magnetic signals. It has the potential of being a fast matching method. The performance of this method is hindered by the accuracy of the poloidal magnetic field computed from the equilibrium solver. A flux reconstruction package has been implemented which integrates a vacuum field solver using a filament model for the plasma, a multi-layer perception neural network as an interface, and the volume integration of plasma current density using Green`s functions as a matching method for the current profile parameters. The flux reconstruction package is applied to compare with the ASEQ and EFIT data. The results are promising.

  1. Current understanding of divertor detachment: experiments and modelling

    Energy Technology Data Exchange (ETDEWEB)

    Wischmeier, W; Groth, M; Kallenbach, A; Chankin, A; Coster, D; Dux, R; Herrmann, A; Muller, H; Pugno, R; Reiter, D; Scarabosio, A; Watkins, J; Team, T D; Team, A U

    2008-05-23

    A qualitative as well as quantitative evaluation of experimentally observed plasma parameters in the detached regime proves to be difficult for several tokamaks. A series of ohmic discharges have been performed in ASDEX Upgrade and DIII-D at similar as possible plasma parameters and at different line averaged densities, {bar n}{sub e}. The experimental data represent a set of well diagnosed discharges against which numerical simulations are compared. For the numerical modeling the fluid-code B2.5 coupled to the Monte Carlo neutrals transport code EIRENE is used. Only the combined enhancement of effects, such as geometry, drift terms, neutral conductance, increased radial transport and divertor target composition, explains a significant fraction of the experimentally observed asymmetries of the ion fluxes as a function of {bar n}{sub e} to the inner and outer target plates in ASDEX Upgrade. The relative importance of the mechanisms leading to detachment are different in DIII-D and ASDEX Upgrade.

  2. Data processing system for spectroscopy at Novillo Tokamak; Sistema de procesamiento de datos para espectroscopia en el Tokamak Novillo

    Energy Technology Data Exchange (ETDEWEB)

    Ortega C, G.; Gaytan G, E. [Instituto Tecnologico de Toluca, Instituto nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    1998-07-01

    Taking as basis some proposed methodologies by software engineering it was designed and developed a data processing system coming from the diagnostic equipment by spectroscopy, for the study of plasma impurities, during the cleaning discharges. the data acquisition is realized through an electronic interface which communicates the computer with the spectroscopy system of Novillo Tokamak. The data were obtained starting from files type text and processed for their subsequently graphic presentation. For development of this system named PRODATN (Processing of Data for Spectroscopy in Novillo Tokamak) was used the LabVIEW graphic programming language. (Author)

  3. Upgrade of the CERN telephone exchange

    CERN Multimedia

    2006-01-01

    As part of the upgrade of telephone services, maintenance work will be carried out on the CERN switching centre between 8.00 p.m. and 10.00 p.m. on Monday 9 October. Telephone services may be disrupted and possibly even interrupted during this time. We apologise in advance for any inconvenience this may cause. CERN TELECOM Service

  4. UPGRADES TO Monteburns, VERSION 3.0

    Energy Technology Data Exchange (ETDEWEB)

    Galloway, Jack D [Los Alamos National Laboratory; Trellue, Holly R [Los Alamos National Laboratory

    2012-06-22

    Monteburns VERSION 3.0 is an upgrade of the existing Monteburns code available through RSICC. The new version includes modern programming style, increased parallel computing, more accurate capture gamma calculations and an automated input generator. This capability was demonstrated through a small PWR core simulation.

  5. Hardware upgrade for A2 data acquisition

    Energy Technology Data Exchange (ETDEWEB)

    Ostrick, Michael; Gradl, Wolfgang; Otte, Peter-Bernd; Neiser, Andreas; Steffen, Oliver; Wolfes, Martin; Koerner, Tito [Institut fuer Kernphysik, Mainz (Germany); Collaboration: A2-Collaboration

    2014-07-01

    The A2 Collaboration uses an energy tagged photon beam which is produced via bremsstrahlung off the MAMI electron beam. The detector system consists of Crystal Ball and TAPS and covers almost the whole solid angle. A frozen-spin polarized target allows to perform high precision measurements of polarization observables in meson photo-production. During the last summer, a major upgrade of the data acquisition system was performed, both on the hardware and the software side. The goal of this upgrade was increased reliability of the system and an improvement in the data rate to disk. By doubling the number of readout CPUs and employing special VME crates with a split backplane, the number of bus accesses per readout cycle and crate was cut by a factor of two, giving almost a factor of two gain in the readout rate. In the course of the upgrade, we also switched most of the detector control system to using the distributed control system EPICS. For the upgraded control system, some new tools were developed to make full use of the capabilities of this decentralised slow control and monitoring system. The poster presents some of the major contributions to this project.

  6. Academic Training - LHC luminosity upgrade: detector challenges

    CERN Multimedia

    Françoise Benz

    2006-01-01

    ACADEMIC TRAINING LECTURE SERIES 13, 14, 15, March, from 11:00 to 12:00 - 16 March from 10:00 to 12:00 Main Auditorium, bldg. 500 on 14, 15 March, Council Room on 13, 16 March LHC luminosity upgrade: detector challenges A. De Roeck / CERN-PH, D. Bortoletto / Purdue Univ. USA, R. Wigmans / Texas, Tech Univ. USA, W. Riegler / CERN-PH, W. Smith / Wisconsin Univ. USA The upgrade of the LHC machine towards higher luminosity (1035 cm-2s-1) has been studied over the last few years. These studies have investigated scenarios to achieve the increase in peak luminosity by an order of magnitude, as well as the physics potential of such an upgrade and the impact of a machine upgrade on the LHC DETECTORS. This series of lectures will cover the following topics: Physics motivation and machine scenarios for an order of magnitude increase in the LHC peak luminosity (lecture 1) Detector challenges including overview of ideas for R&D programs by the LHC experiments: tracking and calorimetry, other new detector ...

  7. Upgrade of the ATLAS Tile Calorimeter Electronics

    CERN Document Server

    Moreno, P; The ATLAS collaboration

    2014-01-01

    The Tile Calorimeter (TileCal) is the hadronic calorimeter covering the central region of the ATLAS experiment at LHC. The TileCal readout consists of about 10000 channels. The bulk of its upgrade will occur for the High Luminosity LHC phase (phase 2) where the peak luminosity will increase 5x compared to the design luminosity (10^34 cm−2s−1) but with maintained energy (i.e. 7+7 TeV). An additional increase of the average luminosity with a factor of 2 can be achieved by luminosity leveling. This upgrade is expected to happen around 2023. The TileCal upgrade aims at replacing the majority of the on- and off-detector electronics to the extent that all calorimeter signals will be digitized and sent to the off-detector electronics in the counting room. To achieve the required reliability, redundancy has been introduced at different levels. Three different options are presently being investigated for the front-end electronic upgrade. Extensive test beam studies will determine which option will be selected. 10 ...

  8. Energy upgrading measures improve also indoor climate

    DEFF Research Database (Denmark)

    Foldbjerg, Peter; Knudsen, Henrik Nellemose

    2014-01-01

    to increase the number of homeowners who venture into a major energy upgrading of their house, the demonstrated positive side effects, more than energy savings, should be included in the communication to motivate homeowners. The barriers should be reduced by “taking the homeowners by the hand” and helping...

  9. Upgrade of the CMS Global Muon Trigger

    CERN Document Server

    Lingemann, Joschka; Sakulin, Hannes; Jeitler, Manfred; Stahl, Achim

    2015-01-01

    The increase in center-of-mass energy and luminosity for Run 2 of the Large Hadron Collider pose new challenges for the trigger systems of the experiments. To keep triggering with a similar performance as in Run 1, the CMS muon trigger is currently being upgraded. The new algorithms will provide higher resolution, especially for the muon transverse momentum and will make use of isolation criteria that combine calorimeter with muon information already in the level-1 trigger. The demands of the new algorithms can only be met by upgrading the level-1 trigger system to new powerful FPGAs with high bandwidth I/O. The processing boards will be based on the new microTCA standard. We report on the planned algorithms for the upgraded Global Muon Trigger (GMT) which combines information from the muon trigger sub-systems and assigns the isolation variable. The upgraded GMT will be implemented using a Master Processor 7 card, built by Imperial College, that features a large Xilinx Virtex 7 FPGA. Up to 72 optical links at...

  10. ATLAS Upgrades Towards the High Luminosity LHC

    CERN Document Server

    Cinca, D; The ATLAS collaboration

    2014-01-01

    After successful LHC operation at the center-of-mass energy of 7 and 8 TeV in 2011 and 2012, plans are actively advancing for a series of upgrades, culminating roughly 10 years from now in the high luminosity LHC (HL-LHC) project, delivering of order five times the LHC nominal instantaneous luminosity along with luminosity levelling. The final goal is to extend the data set from about few hundred fb−1 expected for LHC running to 3000 fb−1 by around 2030. Current planning in ATLAS also has significant upgrades to the detector during the consolidation of the LHC to reach full LHC energy and further upgrades to accommodate running already beyond nominal luminosity this decade. The challenge of coping with HL-LHC instantaneous and integrated luminosity, along with the associated radiation levels, requires further major changes to the ATLAS detector. The designs are developing rapidly for an all-new inner-tracker, significant upgrades in the calorimeter and muon systems, as well as improved triggers and data a...

  11. PC Made Easy: Upgrading Computer Collections.

    Science.gov (United States)

    Hannigan, Matt

    1997-01-01

    Provides guidelines for ordering the best computer books, geared to the library's size. Covers series, articles, subjects, and publishers most useful to a broad audience, as well as the best places to seek information on new titles and where to find reviews. Offers time savers for upgrading a computer book collection and discusses weeding…

  12. Ion cyclotron emission in tokamak plasmas; Emission cyclotronique ionique dans les plasmas de tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Fraboulet, D.

    1996-09-17

    Detection of {alpha}(3.5 MeV) fusion products will be of major importance for the achievement of self sustained discharges in fusion thermonuclear reactors. Due to their cyclotronic gyration in the confining magnetic field of a tokamak, {alpha} particles are suspected to radiate in the radio-frequency band [RF: 10-500 MHz]. Our aim is to determine whether detection of RF emission radiated from a reactor plasma can provide information concerning those fusion products. We observed experimentally that the RF emission radiated from fast ions situated in the core of the discharge is detectable with a probe located at the plasma edge. For that purpose, fast temporal acquisition of spectral power was achieved in a narrow frequency band. We also propose two complementary models for this emission. In the first one, we describe locally the energy transfer between the photon population and the plasma and we compute the radiation equilibrium taking place in the tokamak. {alpha} particles are not the unique species involved in the equilibrium and it is necessary to take into account all other species present in the plasma (Deuterium, Tritium, electrons,...). Our second model consists in the numerical resolution of the Maxwell-Vlasov with the use of a variational formulation, in which all polarizations are considered and the 4 first cyclotronic harmonics are included in a 1-D slab geometry. The development of this second model leads to the proposal for an experimental set up aiming to the feasibility demonstration of a routine diagnostic providing the central {alpha} density in a reactor. (author). 166 refs.

  13. The JLAB 12 GeV Energy Upgrade of CEBAF

    Energy Technology Data Exchange (ETDEWEB)

    Harwood, Leigh H. [JLAB

    2013-12-01

    This presentation should describe the progress of the 12GeV Upgrade of CEBAF at Jefferson Lab. The status of the upgrade should be presented as well as details on the construction, procurement, installation and commissioning of the magnet and SRF components of the upgrade.

  14. The Effect of Recycling in the HL-1M Tokamak

    Institute of Scientific and Technical Information of China (English)

    ZHENGYongzhen

    2002-01-01

    It is often stated that even clean tokamak discharges disrupt at high density. One possibility is that such disruption result from the energy loss arising from hydrogen recycling at the edge of the plasma.this energy loss could lead to a contraction of the current channel and the production of a disruptively unstable configuration.

  15. General Description of Ideal Tokamak MHD Instability Ⅱ

    Institute of Scientific and Technical Information of China (English)

    石秉仁

    2002-01-01

    In this subsequent study on general description of ideal tokamak MHD instability,the part Ⅱ, by using a coordinate with rectified magnetic field lines, the eigenmode equationsdescribing the low-mode-number toroidal Alfven modes (TAE and EAE) are derived through afurther expansion of the shear Alfven equation of motion.

  16. Tokamak Scenario Trajectory Optimization Using Fast Integrated Simulations

    Science.gov (United States)

    Urban, Jakub; Artaud, Jean-François; Vahala, Linda; Vahala, George

    2015-11-01

    We employ a fast integrated tokamak simulator, METIS, for optimizing tokamak discharge trajectories. METIS is based on scaling laws and simplified transport equations, validated on existing experiments and capable of simulating a full tokamak discharge in about 1 minute. Rapid free-boundary equilibrium post-processing using FREEBIE provides estimates of PF coil currents or forces. We employ several optimization strategies for optimizing key trajectories, such as Ip or heating power, of a model ITER hybrid discharge. Local and global algorithms with single or multiple objective functions show how to reach optimum performance, stationarity or minimum flux consumption. We constrain fundamental operation parameters, such as ramp-up rate, PF coils currents and forces or heating power. As an example, we demonstrate the benefit of current over-shoot for hybrid mode, consistent with previous results. This particular optimization took less than 2 hours on a single PC. Overall, we have established a powerful approach for rapid, non-linear tokamak scenario optimization, including operational constraints, pertinent to existing and future devices design and operation.

  17. Solenoid-free plasma start-up in spherical tokamaks

    Science.gov (United States)

    Raman, R.; Shevchenko, V. F.

    2014-10-01

    The central solenoid is an intrinsic part of all present-day tokamaks and most spherical tokamaks. The spherical torus (ST) confinement concept is projected to operate at high toroidal beta and at a high fraction of the non-inductive bootstrap current as required for an efficient reactor system. The use of a conventional solenoid in a ST-based fusion nuclear facility is generally believed to not be a possibility. Solenoid-free plasma start-up is therefore an area of extensive worldwide research activity. Solenoid-free plasma start-up is also relevant to steady-state tokamak operation, as the central transformer coil of a conventional aspect ratio tokamak reactor would be located in a high radiation environment but would be needed only during the initial discharge initiation and current ramp-up phases. Solenoid-free operation also provides greater flexibility in the selection of the aspect ratio and simplifies the reactor design. Plasma start-up methods based on induction from external poloidal field coils, helicity injection and radio frequency current drive have all made substantial progress towards meeting this important need for the ST. Some of these systems will now undergo the final stages of test in a new generation of large STs, which are scheduled to begin operations during the next two years. This paper reviews research to date on methods for inducing the initial start-up current in STs without reliance on the conventional central solenoid.

  18. Current ramps in tokamaks: from present experiments to ITER scenarios

    NARCIS (Netherlands)

    Imbeaux, F.; Citrin, J.; Hobirk, J.; Hogeweij, G. M. D.; Kochl, F.; Leonov, V. M.; Miyamoto, S.; Nakamura, Y.; Parail, V.; Pereverzev, G.; Polevoi, A.; Voitsekhovitch, I.; Basiuk, V.; Budny, R.; Casper, T.; Fereira, J.; Fukuyama, A.; Garcia, J.; Gribov, Y. V.; Hayashi, N.; Honda, M.; Hutchinson, I. H.; Jackson, G.; Kavin, A. A.; Kessel, C. E.; Khayrutdinov, R. R.; Labate, C.; Litaudon, X.; Lomas, P. J.; Lonnroth, J.; Luce, T.; Lukash, V. E.; Mattei, M.; Mikkelsen, D.; Nunes, I.; Peysson, Y.; Politzer, P.; Schneider, M.; Sips, G.; Tardini, G.; Wolfe, S. M.; Zhogolev, V. E.

    2011-01-01

    In order to prepare adequate current ramp-up and ramp-down scenarios for ITER, present experiments from various tokamaks have been analysed by means of integrated modelling in view of determining relevant heat transport models for these operation phases. A set of empirical heat transport models for

  19. Test particle transport in perturbed magnetic fields in tokamaks

    NARCIS (Netherlands)

    de Rover, M.; Schilham, A.M.R.; Montvai, A.; Cardozo, N. J. L.

    1999-01-01

    Numerical calculations of magnetic field line trajectories in a tokamak are used to investigate the common hypotheses that (i) field lines in a chaotic field make a Gaussian random walk and (ii) that the poloidal component of the magnetic field is uniform in regions with a chaotic magnetic field. Bo

  20. Kazakhstan tokamak for material testing conceptual design and basic parameters

    Energy Technology Data Exchange (ETDEWEB)

    Korotkov, V.A. E-mail: korotkov@sintez.niiefa.spb.su; Azizov, E.A.; Cherepnin, Yu.S.; Dokouka, V.N.; Ya.Dvorkin, N.; Khayrutdinov, R.R.; Krylov, V.A.; Kuzmin, E.G.; Leykin, I.N.; Mineev, A.B.; Shkolnik, V.S.; Shestakov, V.P.; Shapovalov, G.V.; Tazhibaeva, I.L.; Tikhomirov, L.N.; Yagnov, V.A

    2001-10-01

    The construction of a special machine for plasma facing material testing under powerful and particle and heat flux deposition is necessary for progress of researches in the field of controlled fusion to industrial application. Kazakhstan tokamak for material testing (KTM) is planned as spherical tokamak with moderate-to-low aspect ratio (A=2) and high plasma and vacuum vessel elongation, that allows to reach high plasma parameters, large power-intensity at a compact arrangement of design elements and low requirements to a toroidal magnetic field. KTM tokamak is planned in order to investigate the following issues: (1) Plasma confinement in tokamak with A=2, plasma parameters and configurations working window; (2) Differed kinds of divertor plates under power flux of plasma to divertor volume; (3) Plasma-wall interaction (different materials and coating) and plasma-limiter configurations. In the paper the basic parameters of the machine are given. The design of magnet system with poloidal field coils, vacuum vessel and divertor are submitted.

  1. Dynamic diagnostics of the error fields in tokamaks

    Science.gov (United States)

    Pustovitov, V. D.

    2007-07-01

    The error field diagnostics based on magnetic measurements outside the plasma is discussed. The analysed methods rely on measuring the plasma dynamic response to the finite-amplitude external magnetic perturbations, which are the error fields and the pre-programmed probing pulses. Such pulses can be created by the coils designed for static error field correction and for stabilization of the resistive wall modes, the technique developed and applied in several tokamaks, including DIII-D and JET. Here analysis is based on the theory predictions for the resonant field amplification (RFA). To achieve the desired level of the error field correction in tokamaks, the diagnostics must be sensitive to signals of several Gauss. Therefore, part of the measurements should be performed near the plasma stability boundary, where the RFA effect is stronger. While the proximity to the marginal stability is important, the absolute values of plasma parameters are not. This means that the necessary measurements can be done in the diagnostic discharges with parameters below the nominal operating regimes, with the stability boundary intentionally lowered. The estimates for ITER are presented. The discussed diagnostics can be tested in dedicated experiments in existing tokamaks. The diagnostics can be considered as an extension of the 'active MHD spectroscopy' used recently in the DIII-D tokamak and the EXTRAP T2R reversed field pinch.

  2. Evidence of Inward Toroidal Momentum Convection in the JET Tokamak

    DEFF Research Database (Denmark)

    Tala, T.; Zastrow, K.-D.; Ferreira, J.

    2009-01-01

    Experiments have been carried out on the Joint European Torus tokamak to determine the diffusive and convective momentum transport. Torque, injected by neutral beams, was modulated to create a periodic perturbation in the toroidal rotation velocity. Novel transport analysis shows the magnitude an...

  3. Bulk Ion Heating with ICRF Waves in Tokamaks

    DEFF Research Database (Denmark)

    Mantsinen, M. J.; Bilato, R.; Bobkov, V. V.

    2015-01-01

    Heating with ICRF waves is a well-established method on present-day tokamaks and one of the heating systems foreseen for ITER. However, further work is still needed to test and optimize its performance in fusion devices with metallic high-Z plasma facing components (PFCs) in preparation of ITER a...

  4. Conceptual design of Remote Control System for EAST tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Sun, X.Y., E-mail: xysun@ipp.ac.cn; Wang, F.; Wang, Y.; Li, S.

    2014-05-15

    Highlights: • A new design conception for remote control for EAST tokamak is proposed. • Rich Internet application (RIA) was selected to implement the user interface. • Some security mechanism was used to fulfill security requirement. - Abstract: The international collaboration becomes popular in tokamak research like in many other fields of science, because the experiment facilities become larger and more expensive. The traditional On-site collaboration Model that has to spend much money and time on international travel is not fit for the more frequent international collaboration. The Remote Control System (RCS), as an extension of the Central Control System for the EAST tokamak, is designed to provide an efficient and economical way to international collaboration. As a remote user interface, the RCS must integrate with the Central Control System for EAST tokamak to perform discharge control function. This paper presents a design concept delineating a few key technical issues and addressing all significant details in the system architecture design. With the aim of satisfying system requirements, the RCS will select rich Internet application (RIA) as a user interface, Java as a back-end service and Secure Socket Layer Virtual Private Network (SSL VPN) for securable Internet communication.

  5. Fokker-Planck Study of Tokamak Electron Cyclotron Resonance Heating

    Institute of Scientific and Technical Information of China (English)

    SHIBingren; LONGYongxing; DONGJiaqi; LIWenzhong; JIAOYiming; WANGAike

    2002-01-01

    In this study, we add a subroutine for describing the electron cyclotron resonant heating calculation to the Fokker-Planck code. By analyzing the wave-particle resonance condition in tokamak plasma and the fast motion of electrons along magnetic field lines, suitable quasi-linear diffusion coefficients are given.

  6. MHD analysis of edge instabilities in the JET tokamak

    NARCIS (Netherlands)

    Perez von Thun, Christian Pedro

    2004-01-01

    The aim of nuclear fusion energy research is to demonstrate the feasibility of nuclear fusion reactors as a future energy source. The tokamak is the most advanced fusion machine to date, and is most likely the first system to be converted into a reactor. An important subject of nuclear fusion resear

  7. Feedback Control for Plasma Position on HL-2A Tokamak

    Institute of Scientific and Technical Information of China (English)

    LIBo; SONGXianming; LILi; LIULi; WANGMinghong; FANMingjie; CHENLiaoyuan; YAOLieying; YANGQingwei

    2003-01-01

    HL-2A is a tokamak with closed divertor. It had been built at the end of 2002 and began to discharge from then on. To further study plasma discharges in HL-2A, a feedback control system (FBCS) for plasma position bad been developed in 2003.

  8. Disruption avoidance through active magnetic feedback in tokamak plasmas

    Science.gov (United States)

    Paccagnella, Roberto; Zanca, Paolo; Yanovskiy, Vadim; Finotti, Claudio; Manduchi, Gabriele; Piron, Chiara; Carraro, Lorella; Franz, Paolo; RFX Team

    2014-10-01

    Disruptions avoidance and mitigation is a fundamental need for a fusion relevant tokamak. In this paper a new experimental approach for disruption avoidance using active magnetic feedback is presented. This scheme has been implemented and tested on the RFX-mod device operating as a circular tokamak. RFX-mod has a very complete system designed for active mode control that has been proved successful for the stabilization of the Resistive Wall Modes (RWMs). In particular the current driven 2/1 mode, unstable when the edge safety factor, qa, is around (or even less than) 2, has been shown to be fully and robustly stabilized. However, at values of qa (qa > 3), the control of the tearing 2/1 mode has been proved difficult. These results suggested the idea to prevent disruptions by suddenly lowering qa to values around 2 where the tearing 2/1 is converted to a RWM. Contrary to the universally accepted idea that the tokamaks should disrupt at low qa, we demonstrate that in presence of a well designed active control system, tokamak plasmas can be driven to low qa actively stabilized states avoiding plasma disruption with practically no loss of the plasma internal energy.

  9. Sensitivity of transient synchrotron radiation to tokamak plasma parameters

    Energy Technology Data Exchange (ETDEWEB)

    Fisch, N.J.; Kritz, A.H.

    1988-12-01

    Synchrotron radiation from a hot plasma can inform on certain plasma parameters. The dependence on plasma parameters is particularly sensitive for the transient radiation response to a brief, deliberate, perturbation of hot plasma electrons. We investigate how such a radiation response can be used to diagnose a variety of plasma parameters in a tokamak. 18 refs., 13 figs.

  10. Pellet Enhanced Performance on the HL-2A Tokamak

    Institute of Scientific and Technical Information of China (English)

    DING Xuan-Tong; LIU Yi; ZHOU Yan; PAN Yu-Dong; CUI Zheng-Ying; HUANG Yuan; LIU Ze-Tian; SHI Zhong-Bing; JI Xiao-Quan; XIAO Wei-Wen; LIU Yong; YANG Qing-Wei; YAN Long-Wen; ZHU Gen-Liang; XIAO Zheng-Gui; LIU De-Quan; CAO Zeng; GAO Qing-Di; LONG Yong-Xing

    2006-01-01

    @@ Enhanced confinement has been achieved by the centre fuelling of pellet injection on the HL-2A tokamak. The energy confinement time increases from 50ms to 140ms after the pellet injection. Experimental results show that the improvement of the confinement is related to the decrease of the electron heat transport.

  11. TPX diagnostics for tokamak operation, plasma control and machine protection

    Energy Technology Data Exchange (ETDEWEB)

    Edmonds, P.H. [Texas Univ., Austin, TX (United States). Fusion Research Center; Medley, S.S.; Young, K.M. [Princeton Univ., NJ (United States). Plasma Physics Lab.] [and others

    1995-08-01

    The diagnostics for TPX are at an early design phase, with emphasis on the diagnostic access interface with the major tokamak components. Account has to be taken of the very severe environment for diagnostic components located inside the vacuum vessel. The placement of subcontracts for the design and fabrication of the diagnostic systems is in process.

  12. Design and construction of Alborz tokamak vacuum vessel system

    Energy Technology Data Exchange (ETDEWEB)

    Mardani, M., E-mail: mohsenmardani@gmail.com [Amirkabir University of Technology (Tehran Polytechnic), Tehran (Iran, Islamic Republic of); Amrollahi, R.; Koohestani, S. [Amirkabir University of Technology (Tehran Polytechnic), Tehran (Iran, Islamic Republic of)

    2012-09-15

    Highlights: Black-Right-Pointing-Pointer The Alborz tokamak is a D-shape cross section tokamak that is under construction in Amirkabir University of Technology. Black-Right-Pointing-Pointer As one of the key components for the device, the vacuum vessel can provide ultra-high vacuum and clean environment for the plasma operation. Black-Right-Pointing-Pointer A limiter is a solid surface which defines the edge of the plasma and designed to protect the wall from the plasma, localizes the plasma-surface interaction and localizes the particle recycling. Black-Right-Pointing-Pointer Structural analyses were confirmed by FEM model for dead weight, vacuum pressure and plasma disruptions loads. - Abstract: The Alborz tokamak is a D-shape cross section tokamak that is under construction in Amirkabir University of Technology. At the heart of the tokamak is the vacuum vessel and limiter which collectively are referred to as the vacuum vessel system. As one of the key components for the device, the vacuum vessel can provide ultra-high vacuum and clean environment for the plasma operation. The VV systems need upper and lower vertical ports, horizontal ports and oblique ports for diagnostics, vacuum pumping, gas puffing, and maintenance accesses. A limiter is a solid surface which defines the edge of the plasma and designed to protect the wall from the plasma, localizes the plasma-surface interaction and localizes the particle recycling. Basic structure analyses were confirmed by FEM model for dead weight, vacuum pressure and plasma disruptions loads. Stresses at general part of the VV body are lower than the structure material allowable stress (117 MPa) and this analysis show that the maximum stresses occur near the gravity support, and is about 98 MPa.

  13. Upgrading of Intermediate Bio-Oil Produced by Catalytic Pyrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Abdullah, Zia [Battelle Memorial Inst., Columbus, OH (United States); Chadwell, Brad [Battelle Memorial Inst., Columbus, OH (United States); Taha, Rachid [Battelle Memorial Inst., Columbus, OH (United States); Hindin, Barry [Battelle Memorial Inst., Columbus, OH (United States); Ralston, Kevin [Battelle Memorial Inst., Columbus, OH (United States)

    2015-06-30

    The objectives of this project were to (1) develop a process to upgrade catalytic pyrolysis bio-oil, (2) investigate new upgrading catalysts suited for upgrading catalytic pyrolysis bio-oil, (3) demonstrate upgrading system operation for more than 1,000 hours using a single catalyst charge, and (4) produce a final upgraded product that can be blended to 30 percent by weight with petroleum fuels or that is compatible with existing petroleum refining operations. This project has, to the best of our knowledge, for the first time enabled a commercially viable bio-oil hydrotreatment process to produce renewable blend stock for transportation fuels.

  14. Vessel and In-Vessel Components Design Upgrade of the FAST machine

    Energy Technology Data Exchange (ETDEWEB)

    Crescenzi, F., E-mail: fabio.crescenzi@enea.it [Associazione EURATOM-ENEA sulla Fusione, C.R. Frascati, Via E. Fermi 45, IT-00044 Frascati (Italy); Roccella, S.; Brolatti, G. [Associazione EURATOM-ENEA sulla Fusione, C.R. Frascati, Via E. Fermi 45, IT-00044 Frascati (Italy); Cao, L. [Institute of Plasma Physics, Chinese Academy of Science, Shushanhu Road 350, Hefei 230031 (China); Crisanti, F.; Cucchiaro, A. [Associazione EURATOM-ENEA sulla Fusione, C.R. Frascati, Via E. Fermi 45, IT-00044 Frascati (Italy); Di Gironimo, G.; Labate, C. [Association Euratom/ENEA/CREATE, DiME, Università Federico II di Napoli, 80125 Napoli (Italy); Lucca, F. [LT Calcoli SaS, Piazza Prinetti 26/B, 23807 Merate (Italy); Maddaluno, G.; Ramogida, G. [Associazione EURATOM-ENEA sulla Fusione, C.R. Frascati, Via E. Fermi 45, IT-00044 Frascati (Italy); Renno, F. [Association Euratom/ENEA/CREATE, DiME, Università Federico II di Napoli, 80125 Napoli (Italy)

    2013-10-15

    Highlights: • One of the most important part of the FAST machine is the Divertor and many efforts have been made to improve the design, the mock-ups manufacturing and so on. • This work deals with the design analysis of the Divertor to help and suggest indications for the mock-ups manufacturing. • The data coming from the results confirm many experimental data, then it could be very useful for the future design optimization. -- Abstract: The Fusion Advanced Study Torus (FAST), with its compact Tokamak design, high toroidal field and plasma current, will face many of the problems that ITER will meet and will anticipate many DEMO relevant physics and technology issues. The Design Upgrade of the Vessel and In-Vessel Components is presented in this paper. Relevant modifications were performed to the Vacuum Vessel (VV) and to the Plasma Facing Components (PFCs), i.e. the First Wall (FW) and the Divertor. The VV was modified to insert active reduction coils (ARC), between VV and the toroidal field (TF) coils to keep toroidal field magnet ripple lower than 0.3% and to allow Remote Handling for the FW and the Divertor. The FW, was modified to house coils for ELMs control and other plasma instabilities. A 3D thermo-hydraulic analysis using ANSYS code was performed to check FW heat removal capability. A new Divertor was designed to withstand the largest thermal loads of the high performance, low density, H-mode and to be able to comply with a recent magnetic topology called as “Snow Flake”, increasing up a factor 4 the flux expansion. An exhaustive 3D thermo-hydraulic analysis using ANSYS code was carried out to show the capability of the Divertor to comply these high requirements. Design criteria were satisfied by present components of the upgraded machine.

  15. First 3D numerical simulations validated with experimental measurements during a LOVA reproduction inside the new facility STARDUST-Upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Ciparisse, J.F.; Malizia, A. [Associazione EUROFUSION-ENEA, Department of Industrial Engineering, University of Rome “Tor Vergata”, Rome 00133 (Italy); Poggi, L.A., E-mail: poggi@ing.uniroma2.it [Associazione EUROFUSION-ENEA, Department of Industrial Engineering, University of Rome “Tor Vergata”, Rome 00133 (Italy); Gelfusa, M. [Associazione EUROFUSION-ENEA, Department of Industrial Engineering, University of Rome “Tor Vergata”, Rome 00133 (Italy); Murari, A. [Consorzio RFX-Associazione EUROFUSION-ENEA per la Fusione, Padova I-35127 (Italy); Mancini, A.; Gaudio, P. [Associazione EUROFUSION-ENEA, Department of Industrial Engineering, University of Rome “Tor Vergata”, Rome 00133 (Italy)

    2015-12-15

    Highlights: • We model supersonic, turbulent 3D flow in the “STARDUST-Upgrade” facility. • We simulate air expansion into a low pressure vessel. • We compare numerical results with experimental results. - Abstract: The aim of this work is to simulate a Loss of Vacuum Accident (LOVA) in the STARDUST (Small Tank for Aerosol Removal and DUST)-UPGRADE facility. These events are one of the major safety concerns in Tokamaks, since they can cause the mobilization and the dispersion of radioactive dust contained in a fusion reactor. The first step in the study of a LOVA event is the estimation, by means of numerical simulations, of the pressurization transient in the vacuum chamber. The STARDUST-UPGRADE facility, which has a cylindrical shape, is considered as a case study. An air inlet is located in a radial position with respect to the facility, so the numerical domain is symmetric and, therefore, only a half of it has been considered in the simulation. A time-dependent mass flow rate is imposed at the inlet, in a range consistent with experimental estimates. The simulation takes 20 s and the attention is focused on the mean pressure value over time and on the Mach number distribution. The results are presented and discussed in the perspective of simulating LOVAs in ITER (International Thermonuclear Experimental Reactor).

  16. LHCb: Upgrade of the LHCb calorimeter electronics

    CERN Multimedia

    Mauricio Ferre, J

    2013-01-01

    The LHCb collaboration foresees a major upgrade of the detector for the high luminosity run that should take place after 2018. Apart from the increase of the instantaneous luminosity at the interaction point of the experiment, one of the major ingredients of this upgrade is a full readout at 40MHz of the sub-detectors and the acquisition of the data by a large farm of PC. The trigger will be done by this farm and should increase the overall trigger efficiency with respect to the current detector, especially in hadronic B meson decays. A general overview of the modifications foreseen to the calorimeter system and the integration of the electromagnetic and hadronic calorimeters in this new scheme will be described.

  17. Social Upgrading in Developing Country Industrial Clusters

    DEFF Research Database (Denmark)

    Pyke, Frank; Lund-Thomsen, Peter

    2016-01-01

    In this article, we examine the role of social upgrading in developing country industrial clusters. We argue that while economic growth and productivity enhancement matter, social conditions within clusters are influenced by state monetary, fiscal, and labour policies and regulations, as well...... as by dynamic processes of agency among cluster governance actors. We find that the state's policies and regulations might enable or constrain cluster actors to behave in ways that affect social upgrading or downgrading. These policies and regulations may also be used by the state to directly change social...... conditions in national contexts, including in cluster settings, in order to further the government's overall economic strategy. The conclusion outlines our main findings, and the research and policy implications of our analysis....

  18. An Upgrade Proposal from the PHENIX Collaboration

    CERN Document Server

    Adare, A; Aidala, C; Ajitanand, N N; Akiba, Y; Akimoto, R; Alexander, J; Aoki, K; Apadula, N; Asano, H; Atomssa, E T; Awes, T C; Azmoun, B; Babintsev, V; Bai, M; Bai, X; Bandara, N; Bannier, B; Barish, K N; Baron, O; Bassalleck, B; Bathe, S; Baublis, V; Baumgart, S; Bazilevsky, A; Beaumier, M; Beckman, S; Belmont, R; Benjamin, G; Berdnikov, A; Berdnikov, Y; Blackburn, J; Blau, D S; Bobrek, M; Bok, J; Boose, S; Boyle, K; Britton,, C L; Brooks, M L; Bryslawskyj, J; Bumazhnov, V; Butler, C; Butsyk, S; Campbell, S; Carollo, A; Chai, J -S; Chen, C -H; Chernichenko, S; Chi, C Y; Chiu, M; Choi, I J; Choi, J B; Choi, S; Chollet, S; Christiansen, P; Chujo, T; Cianciolo, V; Citron, Z; Cole, B A; Cronin, N; Crossett, N; Csanád, M; D'Orazio, L; Dairaku, S; Danley, D; Datta, A; Daugherity, M S; David, G; DeBlasio, K; Debraine, A; Dehmelt, K; Denisov, A; Deshpande, A; Desmond, E J; Dietzsch, O; Ding, L; Dion, A; Diss, P B; Do, J H; Donadelli, M; Drapier, O; Drees, A; Drees, K A; Durham, J M; Durum, A; Eberle, L; Efremenko, Y V; Engelmore, T; Enokizono, A; Esumi, S; Eyser, K O; Fadem, B; Feege, N; Fields, D E; Finger, M; FingerJr., M; Fleuret, F; Fokin, S L; Frantz, J E; Franz, A; Frawley, A D; Fukao, Y; Fusayasu, T; Gainey, K; Gal, C; Gallus, P; Garg, P; Garishvili, A; Garishvili, I; Gastaldi, F; Ge, H; Giannotti, P; Giordarno, F; Glenn, A; Gong, X; Gonin, M; Goto, Y; de Cassagnac, R Granier; Grau, N; Greene, S V; Perdekamp, M Grosse; Gu, Y; Gunji, T; Guragain, H; Hachiya, T; Haggerty, J S; Hahn, K I; Hamagaki, H; Hamilton, H F; Han, S Y; Hanks, J; Hasegawa, S; Haseler, T O S; Hashimoto, K; Hayano, R; Hayashi, S; He, X; Hemmick, T K; Hester, T; Hill, J C; Hoefferkamp, M; Hollis, R S; Homma, K; Hong, B; Hori, Y; Hoshino, T; Huang, J; Huang, S; Hutchins, J R; Ichihara, T; Ikeda, Y; Imai, K; Imazu, Y; Imrek, J; Inaba, M; Iordanova, A; Isenhower, D; Isinhue, A; Isupov, A; Ivanischev, D; Ivanov, V; Jacak, B V; Jeon, S J; Jezghani, M; Jia, J; Jiang, X; Johnson, B M; Joo, K S; Jouan, D; Jumper, D S; Kamin, J; Kanda, S; Kang, B H; Kang, J H; Kang, J S; Kapustinsky, J; Karatsu, K; Kawall, D; Kazantsev, A V; Kehayias, H -J; Key, J A; Khachatryan, V; Khandai, P K; Khanzadeev, A; Kijima, K M; Kim, C; Kim, D H; Kim, D J; Kim, E -J; Kim, H J; Kim, K -B; Kim, M; Kim, Y -J; Kim, Y K; Kimelman, B; Kiss, Á; Kistenev, E; Kitamura, R; Klatsky, J; Kleinjan, D; Kline, P; Koblesky, T; Kochenda, L; Kofarago, M; Komatsu, Y; Komkov, B; Koster, J; Kotchetkov, D; Kotov, D; Kravtsov, P; Krizek, F; Kurita, K; Kuriyama, M; Kurosawa, M; Kwon, Y; Lacey, R; Lai, Y S; Lajoie, J G; Lebedev, A; Lee, G H; Lee, J; Lee, K B; Lee, K S; Lee, S; Lee, S H; Lefferts, R; Leitch, M J; Leite, M A L; Leitgab, M; Lewis, B; Li, X; Lim, S H; Lipski, A; Litvinenko, A; Liu, M X; Love, B; Lynch, D; Lynch, M; Maguire, C F; Makdisi, Y I; Makek, M; Malakhov, A; Manion, A; Manko, V I; Mannel, E; Maruyama, T; Masumoto, S; McCumber, M; McGaughey, P L; McGlinchey, D; McKay, R; McKinney, C; Meles, A; Mendoza, M; Menegasso, R; Meredith, B; Miake, Y; Mibe, T; Mignerey, A C; Milov, A; Mishra, D K; Mitchell, J T; Miyasaka, S; Mizuno, S; Mohanty, A K; Montuenga, P; Moon, T; Morrison, D P; Moskowitz, M; Motschwiller, S; Moukhanova, T V; Murakami, T; Murata, J; Mwai, A; Nagae, T; Nagamiya, S; Nagashima, K; Nagle, J L; Nagy, M I; Nakagawa, I; Nakagomi, H; Nakamiya, Y; Nakamura, K R; Nakamura, T; Nakano, K; Nattrass, C; Nederlof, A; Netrakanti, P K; Nihashi, M; Niida, T; Ninomiya, K; Nishimura, S; Northacker, D; Nouicer, R; Novak, T; Novitzky, N; Nukariya, A; Nyanin, A S; O'Brien, E; Ogilvie, C A; Oide, H; Okada, K; Koop, J D Orjuela; Osborn, J D; Oskarsson, A; Österman, L; Ozawa, K; Pancake, C; Pantuev, V; Papavassiliou, V; Park, I H; Park, J S; Park, S; Park, S K; Pate, S F; Patel, L; Patel, M; Peng, J -C; Perepelitsa, D; Perera, G D N; Peresedov, V; Peressounko, D Yu; Perry, J; Petti, R; Pinkenburg, C; Pinson, R; Pisani, R P; Popule, J; Purschke, M L; Qu, H; Radhakrishnan, S; Rak, J; Ramson, B J; Ravinovich, I; Read, K F; Reynolds, D; Reynolds, R; Riabov, V; Riabov, Y; Richardson, E; Rinn, T; Riveli, N; Roach, D; Rolnick, S D; Rosati, M; Roschin, E; Rowan, Z; Rubin, J G; Rukoyatkin, P; Ryu, M S; Safonov, A; Sahlmueller, B; Saito, N; Sakaguchi, T; Sako, H; Samsonov, V; Sano, M; Sarsour, M; Sato, S; Sawada, S; Schaefer, B; Schmoll, B K; Sedgwick, K; Seele, J; Seidl, R; Sekiguchi, Y; Sen, A; Seto, R; Sett, P; Sexton, A; Shafto, E; Sharma, D; Shaver, A; Shein, I; Shibata, T -A; Shigaki, K; Shimomura, M; Shoji, K; Shukla, P; Sicho, P; Sickles, A; Silva, C L; Silvermyr, D; Singh, B K; Singh, C P; Singh, V; Sippach, F W; Skolnik, M; Snowball, M; Solano, S; Soldatov, A; Soltz, R A; Sondheim, W E; Sorensen, S P; Soumya, M; Sourikova, I V; Stankus, P W; Steinberg, P; Stenlund, E; Stepanov, M; Ster, A; Stevens, L; Stoll, S P; Stone, M R; Sugitate, T; Sukhanov, A; Sumita, T; Sun, J; Sziklai, J; Takagui, E M; Takahara, A; Taketani, A; Tanaka, Y; Tanida, K; Tannenbaum, M J; Tarafdar, S; Taranenko, A; Tarján, P; Tate, A; Tennant, E; Thorsland, E; Tieulent, R; Timilsina, A; Todoroki, T; Torii, H; Towell, C; Towell, R; Towell, R S; Trofimov, V; Tserruya, I; Tsuji, T; Tullo, A; van Hecke, H W; Vargyas, M; Vazquez-Zambrano, E; Veicht, A; Velkovska, J; Vértesi, R; Virius, M; Vrba, V; Vznuzdaev, E; Wang, X R; Watanabe, D; Watanabe, K; Watanabe, Y; Watanabe, Y S; Watson, T S; Wei, F; Wei, R; Whitaker, S; White, A S; Winter, D; Wolin, S; Woody, C L; Wysocki, M; Xia, B; Xue, L; Yalcin, S; Yamaguchi, Y L; Yang, R; Yanovich, A; Yokkaichi, S; Yoo, J H; Yoon, I; Young, M; Younus, I; Yu, H; Yushmanov, I E; Zajc, W A; Zarndt, E; Zelenski, A; Zhang, L; Zhou, S; Zolin, L; Zou, L; Zumberge, C

    2015-01-01

    In this document the PHENIX collaboration proposes a major upgrade to the PHENIX detector at the Relativistic Heavy Ion Collider. This upgrade, sPHENIX, enables an extremely rich jet and beauty quarkonia physics program addressing fundamental questions about the nature of the strongly coupled quark-gluon plasma (QGP), discovered experimentally at RHIC to be a perfect fluid. The startling dynamics of the QGP on fluid-like length scales is an emergent property of quantum chromodynamics (QCD), seemingly implicit in the Lagrangian but stubbornly hidden from view. QCD is an asymptotically free theory, but how QCD manifests as a strongly coupled fluid with specific shear viscosity near $T_C$, as low as allowed by the uncertainty principle, is as fundamental an issue as that of how confinement itself arises.

  19. Biorefining compounds and organocatalytic upgrading methods

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Eugene Y.; Liu, Dajiang

    2016-10-18

    The invention provides new methods for the direct umpolung self-condensation of 5-hydroxymethylfurfural (HMF) by organocatalysis, thereby upgrading the readily available substrate into 5,5'-di(hydroxymethyl)furoin (DHMF). While many efficient catalyst systems have been developed for conversion of plant biomass resources into HMF, the invention now provides methods to convert such nonfood biomass directly into DHMF by a simple process as described herein. The invention also provides highly effective new methods for upgrading other biomass furaldehydes and related compound to liquid fuels. The methods include the organocatalytic self-condensation (umpolung) of biomass furaldehydes into (C.sub.8-C.sub.12)furoin intermediates, followed by hydrogenation, etherification or esterification into oxygenated biodiesel, or hydrodeoxygenation by metal-acid tandem catalysis into premium hydrocarbon fuels.

  20. Primary Vertex Reconstruction for Upgrade at LHCb

    CERN Document Server

    Wanczyk, Joanna

    2016-01-01

    The aim of the LHCb experiment is the study of beauty and charm hadron decays with the main focus on CP violating phenomena and searches for physics beyond the Standard Model through rare decays. At the present, the second data taking period is ongoing, which is called Run II. After 2018 during the long shutdown, the replacement of signicant parts of the LHCb detector is planned. One of main changes is upgrade of the present software and hardware trigger to a more rapid full software trigger. Primary Vertex (PV) is a basis for the further tracking and it is sensitive to the LHC running conditions, which are going to change for the Upgrade. In particular, the center-of-mass collision energy should reach the maximum value of 14 TeV. As a result the quality of the reconstruction has to be studied and the reconstruction algorithms have to be optimized.

  1. Biorefining compounds and organocatalytic upgrading methods

    Science.gov (United States)

    Chen, Eugene Y.; Liu, Dajiang

    2016-10-18

    The invention provides new methods for the direct umpolung self-condensation of 5-hydroxymethylfurfural (HMF) by organocatalysis, thereby upgrading the readily available substrate into 5,5'-di(hydroxymethyl)furoin (DHMF). While many efficient catalyst systems have been developed for conversion of plant biomass resources into HMF, the invention now provides methods to convert such nonfood biomass directly into DHMF by a simple process as described herein. The invention also provides highly effective new methods for upgrading other biomass furaldehydes and related compound to liquid fuels. The methods include the organocatalytic self-condensation (umpolung) of biomass furaldehydes into (C.sub.8-C.sub.12)furoin intermediates, followed by hydrogenation, etherification or esterification into oxygenated biodiesel, or hydrodeoxygenation by metal-acid tandem catalysis into premium hydrocarbon fuels.

  2. ALFA detector upgrade before LHC Run 2

    CERN Document Server

    Vorobel, Vit; The ATLAS collaboration

    2016-01-01

    The operation experience with ATLAS ALFA detectors in the LHC environment during the Run1 period has shown significant beam-induced heating. Subsequent comprehensive studies revealed that heating effects could be disastrous in the case of the larger beam intensities foreseen for higher luminosities in the LHC Run2. During the first LHC long shutdown (LS1) all ALFA detectors have been removed from the LHC tunnel and their covers - Roman Pots - underwent a geometry upgrade to minimize the impedance losses. It will be shown that this modification together with a system improving the internal heat transfer and an air cooling system, significantly shifted the temperatures of ALFA detectors away from the critical limits throughout the LHC Run2. Also ALFA trigger system was considerably upgraded to keep measured data safely inside the Run2 ATLAS latency budget and to minimize dead time. The needed hardware changes of the trigger system will be presented in the second part of the talk.

  3. Phase 2 Upgrade of the CMS Tracker

    CERN Document Server

    Mersi, Stefano

    2014-01-01

    An upgrade program is planned for the LHC which will smoothly bring the luminosity up to or above ${5\\times10^{34}\\,\\mathrm{cm^{-2}}\\mathrm{s^{-1}}}$ sometimes after 2020, to possibly reach an integrated luminosity of ${3000\\,\\mathrm{fb^{-1}}}$ at the end of that decade. In this ultimate scenario, called Phase-2, when LHC will reach the High Luminosity phase (HL-LHC), CMS will need a completely new Tracker detector, in order to fully exploit the highly-demanding operating conditions and the delivered luminosity. The new Tracker should have also trigger capabilities. To achieve such goals, R\\&D activities are ongoing to explore options and develop solutions that would allow including tracking information at Level-1. The design choices for the CMS pixel and outer tracker upgrades are discussed along with some highlights of the R\\&D activities and expected detector performance.

  4. Upgrading the dosimetry at Ontario Hydro

    Energy Technology Data Exchange (ETDEWEB)

    Hirning, C.R. [Ontario Hydro, Whitby, ON (Canada). Health Physics Dept.

    1996-12-01

    Ontario Hydro has embarked upon a major programme to replace and upgrade its external dosimetry systems. In two year`s time, the utility expects to have two state-of-the-art dosimetry systems in place: a new TLD dosimetry of legal record that was designed nearly 30 years ago; and an electronic dosimetry system which could eventually replace the TLD as the primary system. (Author).

  5. Seamounts, Direct Blast and Volume Reverberation Upgrades

    Science.gov (United States)

    1988-11-30

    Highway. Suits 1204. Arlington, VA 22202-4302. "n to the Office of Management and Budget. Peperworik Reduction Project (0704-0188). Washington. DC 2050M. 1...Subtitle. 5. Funding Numbers. Seamounts, Direct Blast And Volume Reverberation Upgrades proram Eemen No 3 7 85N Project No R02017 6. Author(s). L...Section Pae 1 INTRODUCTION ................................. 1-1 2 ASERT: DATA PREPARATION FOR ASTRAL ........... 2-1 2.1 Overview and Purpose of

  6. Upgrading hydro-electric generating facilities

    Energy Technology Data Exchange (ETDEWEB)

    Coulson, D.M.; Villalon, M.

    1987-11-01

    Approximately 1,720,000 kW of installed hydro-electric generating capacity is either owned directly by pulp and paper companies in Canada or is operated principally in their service. The 216 units involved were commissioned between 1902 and 1982. This paper suggests an approach to upgrading the generating units themselves as well as the related electrical and mechanical equipment and civil structures, giving approximate durations and costs. A complete system study is recommended. 2 refs., 2 figs., 3 tabs.

  7. Kicker pulsers for recycler NOVA upgrades

    CERN Document Server

    Jensen, Chris C

    2015-01-01

    An upgrade of the Recycler injection kicker system required a faster rise time pulser. This system required a field rise and fall time of < 57 ns and a field flattop of 1.6 {\\mu}s. This paper describes the variety of improvements made over the years that have resulted in this latest thyratron pulser. The effects of the trigger, the reservoir and the load impedance on delay and rise time will be discussed.

  8. Upgrades of the ATLAS Pixel Detector

    CERN Document Server

    Hügging, F; The ATLAS collaboration

    2013-01-01

    The upgrade for the ATLAS detector will undergo different phases towards HL-LHC. The first upgrade for the Pixel Detector (Phase 1) consists in the construction of a new pixel layer, which will be installed during the 1st long shutdown of the LHC machine (LS1) in 2013/14. The new detector, called Insertable B-Layer (IBL), will be inserted between the existing pixel detector and a new (smaller radius) beam-pipe at a radius of about 3.2 cm. The IBL requires the development of several new technologies to cope with the increase of radiation and pixel occupancy as well as to improve the physics performance of the existing pixel detector. The pixel size is reduced and the material budget is minimized by using new lightweight mechanical support materials and a CO2 based cooling system. For Phase 2 upgrade of LHC a complete new 4-layer pixel system is planned as part of a new all silicon Inner Detector. The increase in luminosity to about $5\\cdot 10^{34}$cm$^{-2}$s$^{-1}$ together with a total expected lifetime of ab...

  9. Proposal to upgrade the MIPP Experiment

    CERN Document Server

    Isenhower, D; Towell, R; Watson, S; Peterson, R J; Baker, W; Carey, D; Christian, D; Demarteau, M; Jensen, D; Johnstone, C; Meyer, H; Raja, R; Ronzhin, A; Solomey, Nickolas; Wester, W; Gutbrod, H H; Peters, K; Feldman, G; Torun, Y; Messier, M D; Paley, J; Akgun, U; Aydin, G; Duru, F; Gülmez, E; Gunaydin, Y; Onel, Y; Penzo, Aldo L; Avdeichikov, V; Leitner, R; Manjavidze, J; Nikitin, V; Rufanov, I; Sisakian, A; Topuria, T; Manley, D M; Löhner, H; Messchendorpfl, J; Gustafson, H R; Longo, M; Nigmanov, T; Rajaram, D; Kruglov, S P; Lopatin, I V; Kozlenko, N G; Kulbardis, A A; Nowinsky, D V; Radkov, A K; Sumachev, V V; Bujak, A; Gutay, L; Godley, A; Mishra, S R; Rosenfeld, C; Dukes, C; Materniak, C; Nelson, K; Norman, A; Desiati, P; Halzen, F; Montaruli, T

    2006-01-01

    The upgraded MIPP physics results are needed for the support of NuMI projects, atmospheric cosmic ray and neutrino programs worldwide and will permit a systematic study of non-perturbative QCD interctions. The MIPP TPC is the largest contributor to the MIPP event size by far. Its readout system and electronics were designed in the 1990's and limit it to a readout rate of 60 Hz in simple events and ~20 Hz in complicated events. With the readout chips designed for the ALICE collaboration at the LHC, we propose a low cost scheme of upgrading the MIPP data acquisition speed to 3000 Hz. This will also enable us to measure the medium energy numi target to be used for the NOvA/MINERvA experiments. We outline the capabilities of the upgraded MIPP detector to obtain high statistics particle production data on a number of nuclei that will help towards the understanding and simulation of hadronic showers in matter. Measurements of nitrogen cross sections will permit a better understanding of cosmic ray shower systematic...

  10. Upgrade of the ATLAS Tile Calorimeter

    CERN Document Server

    Reed, Robert; The ATLAS collaboration

    2014-01-01

    The Tile Calorimeter (TileCal) is the main hadronic calorimeter covering the central region of the ATLAS experiment at LHC. TileCal readout consists of about 10000 channels. The bulk of its upgrade will occur for the High Luminosity LHC operation (Phase 2 around 2023) where the peak luminosity will increase 5x compared to the design luminosity (10^{34} cm^{-2}s^{-1}) but with maintained energy (i.e. 7+7 TeV). The TileCal upgrade aims to replace the majority of the on- and off-detector electronics so that all calorimeter signals can be digitized and directly sent to the off-detector electronics in the counting room. This will reduce pile-up problems and allow more complex trigger algorithms. To achieve the required reliability, redundancy has been introduced at different levels. Three different options are presently being investigated for the front-end electronic upgrade. Extensive test beam studies will determine which option will be selected. 10 Gbps optical links are used to read out all digitized data to t...

  11. Upgrade of the ATLAS Tile Calorimeter

    CERN Document Server

    Moreno, P; The ATLAS collaboration

    2014-01-01

    The Tile Calorimeter (TileCal) is the central hadronic calorimeter covering the central region of the ATLAS experiment at LHC. The TileCal readout consists of about 10000 channels. The bulk of its upgrade will occur for the High Luminosity LHC phase (Phase 2) where the peak luminosity will increase 5$\\times$ compared to the design luminosity ($10^{34} cm^{-2}s^{-1}$) but with maintained energy (i.e. 7+7 TeV). The TileCal upgrade aims at replacing the majority of the on- and off-detector electronics to the extent that all calorimeter signals will be digitized and sent to the off-detector electronics in the counting room. To achieve the required reliability, redundancy has been introduced at different levels. Three different options are presently being investigated for the front-end electronic upgrade. Extensive test beam studies will determine which option will be selected. 10 Gbps optical links are used to read out all digitized data to the counting room while 5 Gbps down-links are used for synchronization, c...

  12. Upgrade of the CMS Global Muon Trigger

    CERN Document Server

    Jeitler, Manfred; Rabady, Dinyar; Sakulin, Hannes; Stahl, Achim

    2015-01-01

    The increase in center-of-mass energy and luminosity for Run-II of the Large Hadron Collider poses new challenges for the trigger systems of the experiments. To keep triggering with a similar performance as in Run-I, the CMS muon trigger is currently being upgraded. The new algorithms will provide higher resolution, especially for the muon transverse momentum and will make use of isolation criteria that combine calorimeter with muon information already in the level-1 trigger. The demands of the new algorithms can only be met by upgrading the level-1 trigger system to new powerful FPGAs with high bandwidth I/O. The processing boards will be based on the new μTCA standard. We report on the planned algorithms for the upgraded Global Muon Trigger (μGMT) which sorts and removes duplicates from boundaries of the muon trigger sub-systems. Furthermore, it determines how isolated the muon candidates are based on calorimetric energy deposits. The μGMT will be implemented using a processing board that features a larg...

  13. LHCb; DAQ Architecture for the LHCb Upgrade

    CERN Multimedia

    Neufeld, N

    2013-01-01

    LHCb will have an upgrade of its detector in 2018. After the upgrade, the LHCb experiment will run at a high luminosity of 2x 10$^{33}$ cm$^{-2}$ . s$^{-1}$. The upgraded detector will be read out at 40 MHz with a highly flexible software-based triggering strategy. The Data Acquisition (DAQ) system of HCb reads out the data fragments from the Front-End Electronics and transports them to the High-Lever Trigger farm at an aggregate throughput of 32 Tbit/s. The DAQ system will be based on high speed network technologies such as InfiniBand and/or 10/40/100 Gigabit Ethernet. Independent of the network technology, there are different possible architectures for the DAQ system. In this paper, we present our studies on the DAQ architecture, where we analyze size, complexity and (relative) cost. We evaluate and compare several data-flow schemes for a network-based DAQ: push, pull and push with barrel-shifter traffic shaping. We also discuss the requirements and overall implications of the data-flow schemes on the DAQ ...

  14. Geotechnical assessments of upgrading power transmission lines

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Andrew [Coffey Geotechnics Ltd., Harrogate (United Kingdom)

    2012-11-01

    One of the consequences of increasing demand for energy is a corresponding requirement for increased energy distribution. This trend is likely to be magnified by the current tendency to generate power in locations remote from centres of population. New power transmission routes are expensive and awkward to develop, and there are therefore benefits to be gained by upgrading existing routes. However, this in turn raises problems of a different nature. The re-use of any structure must necessarily imply the acceptance of unknowns. The upgrading of transmission lines is no exception to this, particularly when assessing foundations, which in their nature are not visible. A risk-based approach is therefore used. This paper describes some of the geotechnical aspects of the assessment of electric power transmission lines for upgrading. It briefly describes the background, then discusses some of the problems encountered and the methods used to address them. These methods are based mainly on information obtained from desk studies and walkover surveys, with a limited amount of intrusive investigation. (orig.)

  15. DAQ Architecture for the LHCb Upgrade

    Science.gov (United States)

    Liu, Guoming; Neufeld, Niko

    2014-06-01

    LHCb will have an upgrade of its detector in 2018. After the upgrade, the LHCb experiment will run at a high luminosity of 2 × 1033 cm-2s-1. The upgraded detector will be read out at 40 MHz with a highly flexible software-based triggering strategy. The Data Acquisition (DAQ) system of LHCb reads out the data fragments from the Front-End Electronics and transports them to the High-Lever Trigger farm at an aggregate throughput of ~ 32 Tbit/s. The DAQ system will be based on high speed network technologies such as InfiniBand and/or 10/40/100 Gigabit Ethernet. Independent of the network technology, there are different possible architectures for the DAQ system. In this paper, we present our studies on the DAQ architecture, where we analyze size, complexity and relative cost. We evaluate and compare several data-flow schemes for a network-based DAQ: push, pull and push with barrel-shifter traffic shaping. We also discuss the requirements and overall implications of the data-flow schemes on the DAQ system.

  16. ATLAS Upgrades for the next Decades

    CERN Document Server

    Gregor, I M; The ATLAS collaboration

    2014-01-01

    After the successful LHC operation at the center-of-mass energies of 7 and 8 TeV in 2010 - 2012, 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 levelling. The final 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. Current planning in ATLAS envisions significant upgrades to the detector during the consolidation of the LHC to reach full LHC energy and further upgrades. The challenge of coping with the HL-LHC instantaneous and integrated luminosity, along with the associated radiation levels, requires further major changes to the ATLAS detector. The designs are developing rapidly fo...

  17. ATLAS upgrades for the next decades

    CERN Document Server

    Hopkins, Walter

    2014-01-01

    After the successful LHC operation at the center-of-mass energies of 7 and 8 TeV in 2010-2012, 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 final goal is to extend the dataset from about few hundred fb$^{-1}$ to 3000 fb$^{-1}$ by around 2035 for ATLAS and CMS. In parallel, the experiments need to be kept lockstep with the accelerator to accommodate running beyond the nominal luminosity this decade. Current planning in ATLAS envisions significant upgrades to the detector during the consolidation of the LHC to reach full LHC energy and further upgrades. The challenge of coping with the HL-LHC instantaneous and integrated luminosity, along with the associated radiation levels, requires further major changes to the ATLAS detector. The designs are developing rapidly for a new all-silicon tr...

  18. ATLAS upgrades for the next decades

    CERN Document Server

    Hopkins, W; The ATLAS collaboration

    2014-01-01

    After the successful LHC operation at the center-of-mass energies of 7 and 8 TeV in 2010-2012, 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 final goal is to extend the dataset from about few hundred \\ifb\\ 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. Current planning in ATLAS envisions significant upgrades to the detector during the consolidation of the LHC to reach full LHC energy and further upgrades. The challenge of coping with the HL-LHC instantaneous and integrated luminosity, along with the associated radiation levels, requires further major changes to the ATLAS detector. The designs are developing rapidly for...

  19. Upgrade of the ATLAS Tile Calorimeter Electronics

    CERN Document Server

    Carrio, F

    2015-01-01

    The Tile Calorimeter (TileCal) is the hadronic calorimeter covering the central region of the ATLAS experiment at LHC. The TileCal readout consists of about 10000 channels. The bulk of its upgrade will occur for the High Luminosity LHC phase (P hase - II ) where the pea k luminosity will increase 5 times compared to the design luminosity (10 34 cm −2 s −1 ) but with maintained energy (i.e. 7+7 TeV). An additional increase of the average luminosity with a factor of 2 can be achieved by luminosity levelling. This upgrade is expe cted to happen around 202 4 . The TileCal upgrade aims at replacing the majority of the on - and off - detector electronics to the extent that all calorimeter signals will be digitized and sent to the off - detector electronics in the counting room. To achieve th e required reliability, redundancy has been introduced at different levels. Three different options are presently being investiga...

  20. Upgrading the ATLAS Tile Calorimeter electronics

    CERN Document Server

    Souza, J; The ATLAS collaboration

    2014-01-01

    The Tile Calorimeter (TileCal) is the hadronic calorimeter covering the central region of the ATLAS experiment at LHC. The TileCal readout consists of about 10000 channels. Its main upgrade will occur for the High Luminosity LHC phase (phase 2) where the peak luminosity will increase 5-fold compared to the design luminosity (10exp34 cm−2s−1) but with maintained energy (i.e. 7+7 TeV). An additional increase of the average luminosity with a factor of 2 can be achieved by luminosity leveling. This upgrade will probably happen around 2023. The upgrade aims at replacing the majority of the on- and off-detector electronics so that all calorimeter signals are directly digitized and sent to the off-detector electronics in the counting room. To achieve the required reliability, redundancy has been introduced at different levels. The smallest independent on-detector electronics module has been reduced from 45 channels to 6, greatly reducing the consequences of a failure in the on-detector electronics. The size of t...

  1. Vacuum system of SST-1 Tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Khan, Ziauddin, E-mail: ziauddin@ipr.res.in [Institute for Plasma Research, Near Indira Bridge, Bhat, Gandhinagar 382 428 (India); Pathan, Firozkhan; George, Siju; Semwal, Pratibha; Dhanani, Kalpesh; Paravastu, Yuvakiran; Thankey, Prashant; Ramesh, Gattu; Himabindu, Manthena; Pradhan, Subrata [Institute for Plasma Research, Near Indira Bridge, Bhat, Gandhinagar 382 428 (India)

    2013-10-15

    Highlights: ► Air leaks developed during ongoing SST-1 cooldown campaign were detected online using RGA. ► The presence of N{sub 2} and O{sub 2} gases with the ratio of their partial pressures with ∼3.81:1 confirmed the air leaks. ► Baking of SST-1 was done efficiently by flowing hot N{sub 2} gas in C-channels welded on inner surfaces without any problem. ► In-house fabricated demountable bull nose couplers were demonstrated for high temperature and pressure applications. ► Cryopumping effect was observed when liquid helium cooled superconducting magnets reached below 63 K. -- Abstract: Vacuum chambers of Steady State Superconducting (SST-1) Tokamak comprises of the vacuum vessel and the cryostat. The plasma will be confined inside the vacuum vessel while the cryostat houses the superconducting magnet systems (TF and PF coils), LN{sub 2} cooled thermal shields and hydraulics for these circuits. The vacuum vessel is an ultra-high (UHV) vacuum chamber while the cryostat is a high-vacuum (HV) chamber. In order to achieve UHV inside the vacuum vessel, it would be baked at 150 °C for longer duration. For this purpose, U-shaped baking channels are welded inside the vacuum vessel. The baking will be carried out by flowing hot nitrogen gas through these channels at 250 °C at 4.5 bar gauge pressure. During plasma operation, the pressure inside the vacuum vessel will be raised between 1.0 × 10{sup −4} mbar and 1.0 × 10{sup −5} mbar using piezoelectric valves and control system. An ultimate pressure of 4.78 × 10{sup −6} mbar is achieved inside the vacuum vessel after 100 h of pumping. The limitation is due to the development of few leaks of the order of 10{sup −5} mbar l/s at the critical locations of the vacuum vessel during baking which was confirmed with the presence of nitrogen gas and oxygen gas with the ratio of ∼3.81:1 indicating air leak. Similarly an ultimate vacuum of 2.24 × 10{sup −5} mbar is achieved inside the cryostat. Baking of the

  2. Fueling studies on the lithium tokamak experiment

    Science.gov (United States)

    Lundberg, Daniel Patrick

    Lithium plasma facing components reduce the flux of "recycled" particles entering the plasma edge from the plasma facing components. This results in increased external fueling requirements and provides the opportunity to control the magnitude and distribution of the incoming particle flux. It has been predicted that the plasma density profile will then be determined by the deposition profile of the external fueling, rather than dominated by the recycled particle flux. A series of experiments on the Lithium Tokamak Experiment demonstrate that lithium wall coatings facilitate control of the neutral and plasma particle inventories. With fresh lithium coatings and careful gas injection programming, over 90% of the injected particle inventory can be absorbed in the lithium wall during a discharge. Furthermore, dramatic changes in the fueling requirements and plasma parameters were observed when lithium coatings were applied. This is largely due to the elimination of water as an impurity on the plasma facing components. A Molecular Cluster Injector (MCI) was developed for the fueling of LTX plasmas. The MCI uses a supersonic nozzle, cooled to liquid nitrogen temperatures, to create the conditions necessary for molecular cluster formation. It has been predicted that molecular clusters will penetrate deeper into plasmas than gas-phase molecules via a reduced ionization cross-section and by improving the collimation of the neutral jet. Using an electron beam diagnostic, the densities of the cryogenic MCI are measured to be an order of magnitude higher than in the room-temperature jets formed with the same valve pressure. This indicates increased collimation relative to what would be expected from ideal gas dynamics alone. A systematic study of the fueling efficiencies achieved with the LTX fueling systems is presented. The fueling efficiency of the Supersonic Gas Injector (SGI) is demonstrated to be strongly dependent on the distance between the nozzle and plasma edge. The

  3. Ion cyclotron resonance heating systems upgrade toward high power and CW operations in WEST

    CERN Document Server

    Hillairet, Julien; Zhao, Yanping; Bernard, Jean-Michel; Song, Yuntao; Argouarch, Arnaud; Berger-By, Gilles; Charabot, Nicolas; Chen, Gen; Chen, Zhaoxi; Colas, Laurent; Delaplanche, Jean-Marc; Dumortier, Pierre; Durodié, Frédéric; Ekedahl, Annika; Fedorczak, Nicolas; Ferlay, Fabien; Goniche, Marc; Hatchressian, Jean-Claude; Helou, Walid; Jacquot, Jonathan; Joffrin, Emmanuel; Litaudon, Xavier; Lombard, Gilles; Maggiora, Riccardo; Magne, Roland; Milanesio, Daniele; Patterlini, Jean-Claude; Prou, Marc; Verger, Jean-Marc; Volpe, Robert; Vulliez, Karl; Wang, Yongsheng; Winkler, Konstantin; Yang, Qingxi; Yuan, Shuai

    2016-01-01

    The design of the WEST (Tungsten-W Environment in Steady-state Tokamak) Ion cyclotron resonance heating antennas is based on a previously tested conjugate-T Resonant Double Loops prototype equipped with internal vacuum matching capacitors. The design and construction of three new WEST ICRH antennas are being carried out in close collaboration with ASIPP, within the framework of the Associated Laboratory in the fusion field between IRFM and ASIPP. The coupling performance to the plasma and the load-tolerance have been improved, while adding Continuous Wave operation capability by introducing water cooling in the entire antenna. On the generator side, the operation class of the high power tetrodes is changed from AB to B in order to allow high power operation (up to 3 MW per antenna) under higher VSWR (up to 2:1). Reliability of the generators is also improved by increasing the cavity breakdown voltage. The control and data acquisition system is also upgraded in order to resolve and react on fast events, such a...

  4. Ion cyclotron resonance heating systems upgrade toward high power and CW operations in WEST

    Energy Technology Data Exchange (ETDEWEB)

    Hillairet, Julien, E-mail: julien.hillairet@cea.fr; Mollard, Patrick; Bernard, Jean-Michel; Argouarch, Arnaud; Berger-By, Gilles; Charabot, Nicolas; Colas, Laurent; Delaplanche, Jean-Marc; Ekedahl, Annika; Fedorczak, Nicolas; Ferlay, Fabien; Goniche, Marc; Hatchressian, Jean-Claude; Helou, Walid; Jacquot, Jonathan; Joffrin, Emmanuel; Litaudon, Xavier; Lombard, Gilles; Magne, Roland; Patterlini, Jean-Claude [CEA, IRFM, F-13108 Saint Paul-lez-Durance (France); and others

    2015-12-10

    The design of the WEST (Tungsten-W Environment in Steady-state Tokamak) Ion cyclotron resonance heating antennas is based on a previously tested conjugate-T Resonant Double Loops prototype equipped with internal vacuum matching capacitors. The design and construction of three new WEST ICRH antennas are being carried out in close collaboration with ASIPP, within the framework of the Associated Laboratory in the fusion field between IRFM and ASIPP. The coupling performance to the plasma and the load-tolerance have been improved, while adding Continuous Wave operation capability by introducing water cooling in the entire antenna. On the generator side, the operation class of the high power tetrodes is changed from AB to B in order to allow high power operation (up to 3 MW per antenna) under higher VSWR (up to 2:1). Reliability of the generators is also improved by increasing the cavity breakdown voltage. The control and data acquisition system is also upgraded in order to resolve and react on fast events, such as ELMs. A new optical arc detection system comes in reinforcement of the V{sub r}/V{sub f} and SHAD systems.

  5. Plasma discharge in ferritic first wall vacuum vessel of the Hitachi Tokamak HT-2

    Energy Technology Data Exchange (ETDEWEB)

    Abe, Mitsushi; Nakayama, Takeshi; Asano, Katsuhiko; Otsuka, Michio [Hitachi Ltd., Tokyo (Japan)

    1997-11-01

    A tokamak discharge with ferritic material first wall was tried successfully. The Hitachi Tokamak HT-2 had a stainless steel SUS304 vacuum vessel and modified to have a ferritic plate first wall for experiments to investigate the possibility of ferritic material usage in magnetic fusion devices. The achieved vacuum pressure and times used for discharge cleaning was roughly identical with the stainless steel first wall or the original HT-2. We concluded that ferritic material vacuum vessel is possible for tokamaks. (author)

  6. Concept definition of KT-2, a large-aspect-ratio diverter tokamak with FWCD

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sung Kyoo; Chang, In Soon; Chung, Moon Kyoo; Hwang, Chul Kyoo; Lee, Kwang Won; In, Sang Ryul; Choi, Byung Ho; Hong, Bong Keun; Oh, Byung Hoon; Chung, Seung Ho; Yoon, Byung Joo; Yoon, Jae Sung; Song, Woo Sub [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of); Chang, Choong Suk; Chang, Hong Yung; Choi, Duk In; Nam, Chang Heui [Korea Advanced Inst. of Science and Technology, Taejon (Korea, Republic of); Chung, Kyoo Sun [Hanyang Univ., Seoul (Korea, Republic of); Hong, Sang Heui [Seoul National Univ., Seoul (Korea, Republic of); Kang, Heui Dong [Kyungpook National Univ., Taegu (Korea, Republic of); Lee, Jae Koo [Pohang Inst. of Science and Technology, Kyungnam (Korea, Republic of)

    1994-11-01

    A concept definition of the KT-2 tokamak is made. The research goal of the machine is to study the `advanced tokamak` physics and engineering issues on the mid size large-aspect-ratio diverter tokamak with intense RF heating (>5 MW). Survey of the status of the research fields, the physics basis for the concept, operation scenarios, as well as machine design concept are presented. (Author) 86 refs., 17 figs., 22 tabs.

  7. Non-axisymmetric equilibrium reconstruction for stellarators, reversed field pinches and tokamaks

    Energy Technology Data Exchange (ETDEWEB)

    Hanson, James D. [Auburn University, Auburn, Alabama; Anderson, D.T. [University of Wisconsin, Madison; Cianciosa, M. [Auburn University, Auburn, Alabama; Franz, P. [EURATOM / ENEA, Italy; Harris, J. H. [Oak Ridge National Laboratory (ORNL); Hartwell, G. H. [Auburn University, Auburn, Alabama; Hirshman, Steven Paul [ORNL; Knowlton, Stephen F. [Auburn University, Auburn, Alabama; Lao, Lang L. [General Atomics, San Diego; Lazarus, Edward Alan [ORNL; Marrelli, L. [Association EURATOM ENEA Fusion, Consorzio RFX, Padua, Italy; Maurer, D. A. [Auburn University, Auburn, Alabama; Schmitt, J. C. [Princeton Plasma Physics Laboratory (PPPL); Sontag, A. C. [Oak Ridge National Laboratory (ORNL); Stevenson, B. A. [Auburn University, Auburn, Alabama; Terranova, D. [Association EURATOM ENEA Fusion, Consorzio RFX, Padua, Italy

    2013-01-01

    Axisymmetric equilibrium reconstruction using magnetohydrodynamic equilibrium solutions to the Grad Shafranov equation has long been an important tool for interpreting tokamak experiments. This paper describes recent results in non-axisymmetric (three-dimensional) equilibrium reconstruction of nominally axisymmetric plasmas (tokamaks and reversed field pinches (RFPs)), and fully non-axisymmetric plasmas (stellarators). Results from applying the V3FIT code to CTH and HSX stellarator plasmas, RFX-mod RFP plasmas and the DIII-D tokamak are presented.

  8. On optimal strategies for upgrading networks

    Energy Technology Data Exchange (ETDEWEB)

    Krumke, S.O.; Noltemeier, H. [Wuerzburg Univ. (Germany). Dept. of Computer Science; Marathe, M.V. [Los Alamos National Lab., NM (United States); Ravi, S.S. [State Univ. of New York, Albany, NY (United States). Dept. of Computer Science; Ravi, R. [Carnegie-Mellon Univ., Pittsburgh, PA (United States). Graduate School of Industrial Administration; Sundaram, R. [Massachusetts Inst. of Tech., Cambridge, MA (United States)

    1996-07-02

    We study {ital budget constrained optimal network upgrading problems}. Such problems aim at finding optimal strategies for improving a network under some cost measure subject to certain budget constraints. Given an edge weighted graph {ital G(V,E)}, in the {ital edge based upgrading model}, it is assumed that each edge {ital e} of the given network has an associated function {ital c(e)} that specifies for each edge {ital e} the amount by which the length {ital l(e)} is to be reduced. In the {ital node based upgrading model} a node {ital v} can be upgraded at an expense of cost {ital (v)}. Such an upgrade reduces the cost of each edge incident on {ital v} by a fixed factor {rho}, where 0 < {rho} < 1. For a given budget, {ital B}, the goal is to find an improvement strategy such that the total cost of reduction is a most the given budget {ital B} and the cost of a subgraph (e.g. minimum spanning tree) under the modified edge lengths is the best over all possible strategies which obey the budget constraint. Define an ({alpha},{beta})-approximation algorithm as a polynomial-time algorithm that produces a solution within {alpha} times the optimal function value, violating the budget constraint by a factor of at most {Beta}. The results obtained in this paper include the following 1. We show that in general the problem of computing optimal reduction strategy for modifying the network as above is {bold NP}-hard. 2. In the node based model, we show how to devise a near optimal strategy for improving the bottleneck spanning tree. The algorithms have a performance guarantee of (2 ln {ital n}, 1). 3. for the edge based improvement problems we present improved (in terms of performance and time) approximation algorithms. 4. We also present pseudo-polynomial time algorithms (extendible to polynomial time approximation schemes) for a number of edge/node based improvement problems when restricted to the class of treewidth-bounded graphs.

  9. A novel approach to linearization of the electromagnetic parameters of tokamaks with an iron core

    Energy Technology Data Exchange (ETDEWEB)

    Fu, P. E-mail: fupeng@mail.ipp.ac.cn; Liu, Z.Z.; Zou, J.H

    2002-05-01

    The equivalent model of an iron core tokamak is developed, in which the electromagnetic parameters of several pairs of coils in opposite series (PCOS) are not dependent on the saturation of the iron core during tokamak operation. With this the electromagnetic parameters of all the coils in an iron core tokamak can be linearized, As an example, the electromagnetic parameters of Hefei Super-conductive Tokamak with iron core (HT-7) are linearized, and it is in good agreement with the experimental results. The linearization approach can be applied in real time plasma control and electromagnetic analysis.

  10. Enhanced confinement regimes and control technology in the DIII-D tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Lohr, J.; Burrell, K.H. [General Atomics, San Diego, CA (United States); Coda, S. [Massachusetts Inst. of Tech., Cambridge, MA (United States)] [and others

    1993-07-01

    Advanced tokamak performance has been demonstrated in the DIII-D tokamak in a series of experiments which brought together developments in technology and improved understanding of the physical principles underlying tokamak operation. The achievement of greatly improved confinement coupled with development of new systems for real time plasma control have permitted investigation of the heretofore hidden or poorly controlled variables which together determine global confinement. These experiments, which included work in transport and control of the plasma boundary, point toward development of operationally and economically attractive reactors based on the tokamak. Some of these experiments are described.

  11. Upgrade of a 30 kV/10 mA anode power supply for triode type gyrotron

    Energy Technology Data Exchange (ETDEWEB)

    Siravo, Ugo, E-mail: ugo.siravo@epfl.ch; Alberti, Stefano; Dubray, Jérémie; Fasel, Damien; Hogge, Jean-Philippe; Marlétaz, Blaise; Marmillod, Philippe; Perez, Albert; Silva, Miguel

    2015-10-15

    Highlights: • Triode type gyrotron is fed by 3 power supplies: the main, an anode PS(APS) and a heater. • This paper presents the upgrade of 3APS, supplied in 1999, that never fulfilled the specs. • The new working principle is very efficient, easy to implement, for a minimal cost. • Upgraded APS provides extended modulation capabilities, no overshoot and lowerripple. • This upgrade will allow exploring new operation regimes for the 3 TCV X3 gyrotrons. - The RF power of a gyrotron with a triode type magnetron-injection-gun (MIG) can be directly controlled via the voltage applied between its anode and its cathode. Hence, the performance of this type of gyrotron relies directly on the possibilities offered by the power supply controlling the anode to cathode voltage. For a system of gyrotrons connected to the same main high-voltage power supply, with a triode MIG one has the additional advantage of independently controlling each individual gyrotron. This paper presents the modifications brought to the three existing 30 kV/10 mA anode power supplies connected to the 500 kW/118 GHz/2s X3 gyrotrons operated on the TCV Tokamak. The new working principle based on phase-shift modulation (PSM) is described in detail. Experimental results obtained on dummy load are compared to simulations performed during the design phase. With respect to the initial working principle, the modulation frequency capability has been increased by a factor 10 reaching more than 5 kHz, whereas the output voltage ripple as well as the overshoot/undershoot have been significantly reduced.

  12. Analytical solutions for Tokamak equilibria with reversed toroidal current

    Energy Technology Data Exchange (ETDEWEB)

    Martins, Caroline G. L.; Roberto, M.; Braga, F. L. [Departamento de Fisica, Instituto Tecnologico de Aeronautica, Sao Jose dos Campos, Sao Paulo 12228-900 (Brazil); Caldas, I. L. [Instituto de Fisica, Universidade de Sao Paulo, 05315-970 Sao Paulo, SP (Brazil)

    2011-08-15

    In tokamaks, an advanced plasma confinement regime has been investigated with a central hollow electric current with negative density which gives rise to non-nested magnetic surfaces. We present analytical solutions for the magnetohydrodynamic equilibria of this regime in terms of non-orthogonal toroidal polar coordinates. These solutions are obtained for large aspect ratio tokamaks and they are valid for any kind of reversed hollow current density profiles. The zero order solution of the poloidal magnetic flux function describes nested toroidal magnetic surfaces with a magnetic axis displaced due to the toroidal geometry. The first order correction introduces a poloidal field asymmetry and, consequently, magnetic islands arise around the zero order surface with null poloidal magnetic flux gradient. An analytic expression for the magnetic island width is deduced in terms of the equilibrium parameters. We give examples of the equilibrium plasma profiles and islands obtained for a class of current density profile.

  13. On the Production of Relativistic Runaway Electrons in Damavand Tokamak

    Science.gov (United States)

    Moslehi-Fard, Mahmoud

    2013-02-01

    Experimental observations in Damavand tokamak show that hard X-ray is produced by either disruption with I p 20 kA. Hard X-ray also persists from the initiation of plasma discharge to the end. Occurrence of multiple spikes in hard X-ray during the discharge is evident. The propagation of hard X-ray is attributed to runaway electrons. We observe runaway electrons in two regimes with different characteristics. Regime (RADI) is similar to the observations of other Tokamak during disruption on that the plasma current is reduced abruptly and interpreted by Dreicer theory. In the regime of RADII, hard X-ray and subsequently runaway electrons are observed from starting of plasma discharge which provides the condition that the most of runaway electrons contain the toroidal plasma current. Runaway electron beam excites whistler waves and scattered electrons in velocity space and prevent growing the runaway electrons beam.

  14. Plasma shaping effects on tokamak scrape-off layer turbulence

    Science.gov (United States)

    Riva, Fabio; Lanti, Emmanuel; Jolliet, Sébastien; Ricci, Paolo

    2017-03-01

    The impact of plasma shaping on tokamak scrape-off layer (SOL) turbulence is investigated. The drift-reduced Braginskii equations are written for arbitrary magnetic geometries, and an analytical equilibrium model is used to introduce the dependence of turbulence equations on tokamak inverse aspect ratio (ε ), Shafranov’s shift (Δ), elongation (κ), and triangularity (δ). A linear study of plasma shaping effects on the growth rate of resistive ballooning modes (RBMs) and resistive drift waves (RDWs) reveals that RBMs are strongly stabilized by elongation and negative triangularity, while RDWs are only slightly stabilized in non-circular magnetic geometries. Assuming that the linear instabilities saturate due to nonlinear local flattening of the plasma gradient, the equilibrium gradient pressure length {L}p=-{p}e/{{\

  15. Transition to subcritical turbulence in a tokamak plasma

    CERN Document Server

    van Wyk, F; Schekochihin, A A; Roach, C M; Field, A R; Dorland, W

    2016-01-01

    Unstable perturbations driven by the pressure gradient and other sources of free energy in tokamak plasmas can grow exponentially and eventually saturate nonlinearly, leading to turbulence. Recent work has shown that in the presence of sheared flows, such systems can be subcritical. This means that all perturbations are linearly stable and a transition to a turbulent state only occurs if large enough initial perturbations undergo sufficient transient growth to allow nonlinear interaction. There is, however, currently very little known about a subcritical transition to turbulence in fusion-relevant plasmas. Here we use first-principles gyrokinetic simulations of a turbulent plasma in the outer core of the Mega-Ampere Spherical Tokamak (MAST) to demonstrate that the experimentally observed state is near the transition threshold, that the turbulence in this state is subcritical, and that transition to turbulence occurs via accumulation of very long-lived, intense, finite-amplitude coherent structures, which domi...

  16. Analysis on the severe accidents in KSTAR tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Myoung Jae; Cheong, Y. H.; Choi, Y. S.; Cheon, E. J. [PlaGen, Seoul (Korea, Republic of)

    2003-11-15

    The establishment of regulatory and approval systems for KSTAR (Korea Superconducting Tokamak Advanced Research) has been demanded as the facility is targeted to be completed in the year of 2005. Such establishment can be achieved by performing adequate and in-depth analyses on safety issues covering radiological and chemical hazard materials, radiation protection, high vacuum, very low temperature, etc. The loss of coolant accidents and the loss of vacuum accident in fusion facilities have been introduced with summary of simulation results that were previously reported for ITER and JET. Computer codes that are actively used for accident simulation research are examined and their main features are briefly described. It can be stated that the safety analysis is indispensable to secure the safety of workers and individual members of the public as well as to establish the regulatory and approval systems for KSTAR tokamak.

  17. Imaging System and Plasma Imaging on HL-2A Tokamak

    Institute of Scientific and Technical Information of China (English)

    郑银甲; 冯震; 罗萃文; 刘莉; 李伟; 严龙文; 杨青巍; 刘永

    2004-01-01

    As a new diagnostic means, plasma-imaging system has been developed on the HL2A tokamak, with a basic understanding of plasma discharge scenario of the entire torus, checking the plasma position and the clearance between the plasma and the first wall during discharge. The plasma imaging system consists of (1) color video camera, (2) observation window and turn mirror,(3) viewing & collecting optics, (4) video cable, (5) Video capture card as well as PC. This paper mainly describes the experimental arrangement, plasma imaging system and detailed part in the system, along with the experimental results. Real-time monitoring of plasma discharge process,particularly distinguishing limitor and divertor configuration, the imaging system has become key diagnostic means and laid the foundation for further physical experiment on the HL-2A tokamak.

  18. Operation of cryostat vacuum vessel of HT-7 superconducting tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Y. [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China)]. E-mail: yangyu@ipp.ac.cn; Su, M. [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China)

    2006-11-15

    The superconducting tokamak HT-7 has been in operation for over 10 years. The safe and reliable operation of its cryostat vacuum vessel, which contains the superconducting coils is essential for each experimental run since the superconducting toroidal field coils are contained inside the vessel. In this paper, the operation is reviewed with the emphasis on the analysis on anomalous pressure rises and the corresponding solutions. It is shown that under close monitoring and timely handling, the cryostat vacuum vessel could still satisfy the requirements of the experimental operation despite of the material aging. This provides guideline for vacuum operating of HT-7. The experiences should be valuable for other superconducting projects as well, including a whole superconducting tokamak under construction, EAST.

  19. 3D MHD disruptions simulations of tokamaks plasmas

    Science.gov (United States)

    Paccagnella, Roberto; Strauss, Hank; Breslau, Joshua

    2008-11-01

    Tokamaks Vertical Displacement Events (VDEs) and disruptions simulations in toroidal geometry by means of a single fluid visco-resistive magneto-hydro-dynamic (MHD) model are presented in this paper. The plasma model, implemented in the M3D code [1], is completed with the presence of a 2D homogeneous wall with finite resistivity. This allows the study of the relatively slowly growing magneto-hydro-dynamical perturbation, the resistive wall mode (RWM), which is, in this work, the main drive of the disruptions. Amplitudes and asymmetries of the halo currents pattern at the wall are also calculated and comparisons with tokamak experimental databases and predictions for ITER are given. [1] W. Park, E.V. Belova, G.Y. Fu, X.Z. Tang, H.R. Strauss, L.E. Sugiyama, Phys. Plasmas 6 (1999) 1796.

  20. Multipoint Thomson scattering diagnostic for the ETE tokamak

    Science.gov (United States)

    Berni, L. A.; Alonso, M. P.; Oliveira, R. M.

    2004-10-01

    To measure the electron temperature and plasma density profiles on the Experimento Tokamak Esférico tokamak a multiplexed Thomson scattering diagnostic was implemented. The diagnostic is based on a 10 J ruby laser and a single five spectral channel filter polychromator. A collection lens with f/6.3 relay the scattered light from 23 spatial points to optical fibers. The fibers have a monotonous increasing length and are inserted into the polychromator. Between the collection lens and each fiber optic we have a microlens to match the numerical aperture and to enlarge the plasma observation volume. This work describes the project, the simulations, and the preliminary results obtained with the first four optical fibers.