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1. Overview of power exhaust experiments in the COMPASS divertor with liquid metals

Author

R. Dejarnac, J. Horacek, M. Hron, M. Jerab, J. Adamek, S. Atikukke, P. Barton, J. Cavalier, J. Cecrdle, M. Dimitrova, E. Gauthier, M. Iafrati, M. Imrisek, A. Marin Roldan, G. Mazzitelli, D. Naydenkova, A. Prishvitcyn, M. Tomes, D. Tskhakaya, G. Van Oost, J. Varju, P. Veis, A. Vertkov, P. Vondracek, and V. Weinzettl

Subjects
CPS, ELM, Divertor, Tokamak, Liquid metal, COMPASS, Nuclear engineering. Atomic power, TK9001-9401
Abstract

Power handling experiments with a special liquid metal divertor module based on the capillary porous system technology were performed in the tokamak COMPASS. The performance of two metals (Li and LiSn alloy) were tested for the first time in a divertor under ELMy H-mode conditions. No damage of the capillary mesh and a good exhaust capability were observed for both metals in two separate experiments with up to 12 MW/m2 of deposited perpendicular, inter-ELM steady-state heat flux and with ELMs of relative energy ~3% and a local peak energy fluence at the module ~15 kJ.m−2. No droplets were directly ejected from the mesh top surface and for the LiSn experiment, no contamination of the core and SOL plasmas by Sn was observed. The elemental depth profile analysis of 14 stainless-steel samples located around the vacuum vessel for each experiment provides information about the migration of evaporated/redeposited liquid elements.

Published
2020
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2. Modeling of COMPASS tokamak divertor liquid metal experiments

Author

J. Horacek, R. Dejarnac, J. Cecrdle, D. Tskhakaya, A. Vertkov, J. Cavalier, P. Vondracek, M. Jerab, P. Barton, G. van Oost, M. Hron, V. Weinzettl, D. Sestak, S. Lukes, J. Adamek, A. Prishvitsin, M. Iafratti, Y. Gasparyan, Y. Vasina, D. Naydenkova, J. Seidl, E. Gauthier, G. Mazzitelli, M. Komm, J. Gerardin, J. Varju, M. Tomes, S. Entler, J. Hromadka, and R. Panek

Subjects
Tokamak, Divertor, Liquid metals, Plasma facing components, Nuclear engineering. Atomic power, TK9001-9401
Abstract

Two small liquid metal targets based on the capillary porous structure were exposed to the divertor plasma of the tokamak COMPASS. The first target was wetted by pure lithium and the second one by a lithium-tin alloy, both releasing mainly lithium atoms (sputtering and evaporation) when exposed to plasma. Due to poorly conductive target material and steep surface inclination (implying the surface-perpendicular plasma heat flux 12–17 MW/m2) for 0.1–0.2 s, the LiSn target has reached 900 °C under ELMy H-mode. A model of heat conduction is developed and serves to evaluate the lithium sputtering and evaporation and, thus, the surface cooling by the released lithium and consequent radiative shielding. In these conditions, cooling of the surface by the latent heat of vapor did not exceed 1 MW/m2. About 1019 lithium atoms were evaporated (comparable to the COMPASS 1 m3 plasma deuterium content), local Li pressure exceeded the deuterium plasma pressure. Since the radiating Li vapor cloud spreads over a sphere much larger than the hot spot, its cooling effect is negligible (0.2 MW/m2). We also predict zero lithium prompt redeposition, consistent with our observation.

Published
2020
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3. Overview of the COMPASS results

Author

M. Hron, J. Adámek, J. Cavalier, R. Dejarnac, O. Ficker, O. Grover, J. Horáček, M. Komm, E. Macúšová, E. Matveeva, R. Pánek, M. Peterka, J. Seidl, D. Tskhakaya, V. Yanovskiy, F.J. Artola, S. Atikukke, P. Bartoň, A. Bencze, M. Berta, P. Bílková, W. Bin, K. Bogár, O. Bogár, P. Böhm, I. Borodkina, S. Brezinsek, F. Brochard, P. Buratti, J. Čaloud, A. Casolari, C. Castaldo, J. Čečrdle, J. Čeřovský, D. Cipciar, A. Devitre, M. Dimitrova, I. Ďuran, S. Entler, M. Farník, H. Fernandes, D. Fridrich, Š. Fuková, E. Gauthier, J. Gerardin, M. Gobbin, G. Grenfell, Y. Gribov, M. Grof, J. Gunn, P. Háček, J. Havlíček, A. Havránek, C. Hidalgo, K. Hromasová, O. Hronova, M. Iafrati, M. Imríšek, N. Isernia, F. Jaulmes, M. Jeřáb, M. Jirsa, P. Junek, A. Kallenbach, O. Kovanda, K. Kovařík, J. Krbec, L. Kripner, L. Krlín, P. Kulhánek, M. Lehnen, N. Lemoine, X. Litaudon, Y.Q. Liu, N.C. Logan, T. Loarer, A. Loarte, P. Lourenco, S. Lukes, P. Mácha, M. Rabinski, A. Marin Roldan, T. Markovič, J. Matějíček, G. Mazzitelli, J. Mlynář, I. Mysiura, F. Napoli, D. Naydenkova, J.-K. Park, N. Patel, P. Pavlo, R. Pitts, A. Podolník, M. Poradzinski, J. Preinhaelter, A. Prishvitsin, D. Refy, R. Roccella, D. Šesták, O. Shyshkin, V. Škvára, M. Šos, M. Spolaore, J. Stöckel, J. Svoboda, M. Tomeš, A. Torres, P. Turjanica, G. Tynan, M. Valovič, G. Van Oost, M. Varavin, J. Varju, P. Veis, M. Vilemova, F. Villone, P. Vondráček, V. Weinzettl, F. Žáček, G. Zadvitskiy, J. Zajac, D.R. Zaloga, J. Zebrowski, S. Zoletnik, Institut Jean Lamour (IJL), Institut de Chimie du CNRS (INC)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), CEA Cadarache, Commissariat à l'énergie atomique et aux énergies alternatives (CEA), and Université de Lorraine (UL)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Nuclear and High Energy Physics, Engineering drawing, Engineering, disruptions, 01 natural sciences, 010305 fluids & plasmas, Physics::Plasma Physics, [PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], plasma–material interaction, Compass, 0103 physical sciences, 010306 general physics, nuclear fusion, ComputingMilieux_MISCELLANEOUS, business.industry, [SPI.PLASMA]Engineering Sciences [physics]/Plasmas, runaway electrons, Condensed Matter Physics, MODEL, COMPASS tokamak, H-mode, Physics and Astronomy, plasma-material interaction, ddc:620, tokamak physics, business
Abstract

COMPASS addressed several physical processes that may explain the behaviour of important phenomena. This paper presents results related to the main fields of COMPASS research obtained in the recent two years, including studies of turbulence, L–H transition, plasma material interaction, runaway electron, and disruption physics: Tomographic reconstruction of the edge/SOL turbulence observed by a fast visible camera allowed to visualize turbulent structures without perturbing the plasma. Dependence of the power threshold on the X-point height was studied and related role of radial electric field in the edge/SOL plasma was identified. The effect of high-field-side error fields on the L–H transition was investigated in order to assess the influence of the central solenoid misalignment and the possibility to compensate these error fields by low-field-side coils. Results of fast measurements of electron temperature during ELMs show the ELM peak values at the divertor are around 80% of the initial temperature at the pedestal. Liquid metals were used for the first time as plasma facing material in ELMy H-mode in the tokamak divertor. Good power handling capability was observed for heat fluxes up to 12 MW m−2 and no direct droplet ejection was observed. Partial detachment regime was achieved by impurity seeding in the divertor. The evolution of the heat flux footprint at the outer target was studied. Runaway electrons were studied using new unique systems—impact calorimetry, carbon pellet injection technique, wide variety of magnetic perturbations. Radial feedback control was imposed on the beam. Forces during plasma disruptions were monitored by a number of new diagnostics for vacuum vessel (VV) motion in order to contribute to the scaling laws of sideways disruption forces for ITER. Current flows towards the divertor tiles, incl. possible short-circuiting through PFCs, were investigated during the VDE experiments. The results support ATEC model and improve understanding of disruption loads.

Published
2021

4. Constraints on conceptual design of diagnostics for the high magnetic field COMPASS-U tokamak with hot walls

Author

A. Casolari, F. Jaulmes, A. Podolnik, Jordan Cavalier, D. Sestak, M. Peterka, Petra Bilkova, P. Bohm, M. Tomes, Vladimir Weinzettl, J. Adamek, P. Hacek, Josef Havlicek, Jozef Varju, Petr Vondracek, O. Bogar, R. Dejarnac, J. Zajac, Ondrej Ficker, D. Naydenkova, Radomir Panek, Miglena Dimitrova, J. Krbec, K. Kovarik, L. Kripner, Martin Imrisek, Martin Hron, I. Duran, M. Sos, Tomas Markovic, M. Varavin, F. Pova, J. Horacek, and Slavomir Entler

Subjects
Physics, Tokamak, Mechanical Engineering, Nuclear engineering, Divertor, 01 natural sciences, 010305 fluids & plasmas, law.invention, Magnetic field, Nuclear Energy and Engineering, Conceptual design, law, Compass, 0103 physical sciences, General Materials Science, New device, Plasma diagnostics, 010306 general physics, High magnetic field, Civil and Structural Engineering
Abstract

COMPASS-U, a high magnetic field tokamak with hot walls, will be designed and built at IPP Prague. Unique features of this new device bring noticeable constraints and requirements on plasma diagnostics, which make their development highly demanding. In this paper, the main expected constraints influencing the conceptual design of diagnostic tools for COMPASS-U (high temperature of the vacuum vessel, high plasma density, high heat flux density, strong auxiliary plasma heating, spatial constraints, liquid metals in the divertor) are reviewed and possible solutions are indicated.

Published
2019

5. Study for the microwave interferometer for high densities plasmas on COMPASS-U tokamak

Author

A. V. Varavin, S. Nanobashvili, M. Varavin, Petra Bilkova, Martin Imrisek, M. Farnik, Vladimir Weinzettl, F. Jaulmes, D. Naydenkova, J. Zajac, F. Zacek, O. Bogar, Radomir Panek, and K. Kovarik

Subjects
Physics, Tokamak, COMPASS tokamak, business.industry, Mechanical Engineering, Plasma, 01 natural sciences, 010305 fluids & plasmas, law.invention, Magnetic field, Wavelength, Interferometry, Optics, Nuclear Energy and Engineering, law, Compass, 0103 physical sciences, General Materials Science, 010306 general physics, business, Microwave, Civil and Structural Engineering
Abstract

The present COMPASS tokamak at the Institute of Plasma Physics in Prague is equipped with the 2-mm interferometer, which gives a possibility to measure line-average electron densities up to 1.2×1020 m−3. A high magnetic field tokamak COMPASS-U will be designed and built to replace COMPASS. Higher line-average plasma densities in COMPASS-U of about 5×1020 m−3 will require a new design of the interferometer. This will provide measurements in a wide density range and will allow using a real-time gas puff density feedback. A solution based on the solid-state technology is proposed. The system will use two microwave transceivers with close sub-millimeter wavelengths and will fulfill the principle of the unambiguous measurement. An assessment of signal corrections corresponding to non-linearity effects caused by plasma refractive index is performed. The ray-tracing FIESTA-8 code was used to model the propagation of the probing waves through COMPASS-U plasmas.

Published
2019

6. Power exhaust by core radiation at COMPASS tokamak

Author

Olivier Février, Martin Hron, M. Sos, M. Bernert, L. Kripner, Matthias Komm, S. S. Henderson, Martin Imrisek, D. Mancini, D. Naydenkova, M. Morbey, Petra Bilkova, P. Bohm, Radomir Panek, Jordan Cavalier, D. Brida, J. Adamek, Petr Vondracek, M. Jerab, EUROfusion MST1 Team, Science and Technology of Nuclear Fusion, and Applied Physics and Science Education

Subjects
Nuclear and High Energy Physics, Materials science, Tokamak, Thermonuclear fusion, Detachment, Impurity seeding, Neon, 7. Clean energy, 01 natural sciences, 010305 fluids & plasmas, law.invention, Plasma, law, Physics::Plasma Physics, 0103 physical sciences, Argon, 010306 general physics, Pressure gradient, COMPASS tokamak, Divertor, Mechanics, Fusion power, Dissipation, Condensed Matter Physics, Heat flux, Nuclear fusion
Abstract

Substantial power dissipation in the edge plasma is required for the safe operation of ITER and next-step fusion reactors, otherwise unmitigated heat fluxes at the divertor plasma-facing components (PFCs) would easily exceed their material limits. Traditionally, such heat flux mitigation is linked to the regime of detachment, which is characterised by a significant pressure gradient between upstream and downstream scrape-off layer (SOL). However, the physics phenomena responsible for power dissipation and pressure loss are distinctly different, especially when the power dissipation is achieved by impurity seeding. In principle, it is possible to achieve substantial mitigation of the heat fluxes while maintaining conservation of the pressure along the open field lines in the SOL. This regime can be accessed by injection of medium- or high-Z impurities, which mostly radiate inside the last closed flux surface. The critical question related to such an approach is the effect on confinement and perspective fusion power generation in future thermonuclear reactors. In this work, we report on experiments at COMPASS tokamak, where neon and argon impurities were injected in ohmic or NBI-heated low confinement plasmas. With appropriate seeding waveform, stable scenarios were achieved, avoiding the radiative collapse of plasmas. Significant reduction of heat fluxes at the outer target was observed, with heat flux pattern similar to the one previously achieved by nitrogen seeding. The reduction of downstream pressure was, however, accompanied by an equal reduction of upstream pressure, indicating that the power dissipation occurred inside the separatrix. Indeed, the impurity cooling is causing a significant drop of edge temperature; however, the effect in the plasma centre is much less pronounced.

Published
2021

7. Preliminary design of the COMPASS upgrade tokamak

Author

M. Farnik, Andre Torres, J. Blocki, I. Hanak, M. Tomes, Miglena Dimitrova, I. Duran, Jakub Bielecki, F. Prochazka, J. Fang, D. Zaloga, P. Barton, G. Cunningham, Ondrej Ficker, Jozef Varju, Martin Hron, Pavel Turjanica, Jacek Swierblewski, J. Horacek, V. Yanovskiy, Martin Imrisek, M. Kral, M. Sos, J. Gerardin, Han Zhang, P. Boocz, Matthias Komm, Robert Ellis, Jan Prevratil, J. Adamek, N. Isernia, M. Balazsova, O. Hronova, D. Fridrich, T. Majer, Marek Scholz, P. Chappuis, J. Svoboda, Petr Vondracek, O. Bogar, Slavomir Entler, V. Balner, V. Veselovsky, J. Krbec, L. Kripner, N. Patel, M. Mohelnik, F. Jaulmes, A. Zak, A. Brooks, M. Jerab, D. Tskhakaya, Dariusz Bocian, Fabio Villone, K. Bogar, D. Naydenkova, Radomir Panek, E. Matveeva, Vladimir Kindl, P. Junek, Jordan Cavalier, A. Herrmann, M. Varavin, Peter Titus, M. Peterka, Eva Macusova, I. Borodkina, I. Nemec, A. Havranek, A. Casolari, J. Zelda, J. Burant, K. Kovarik, J. Hromadka, I. Mysiura, Przemysław Wąchal, S. Fukova, G. Zadvitskiy, Grzegorz Tracz, R. Dejarnac, J. Zajac, Jan Reboun, Vladimir Weinzettl, M. Tadros, K. Mikszuta-Michalik, Tomas Markovic, K. Patocka, Rafal Ortwein, D. Sestak, Josef Havlicek, P. Hacek, A. Podolnik, V. Scalera, M. Dudak, Petra Bilkova, P. Bohm, and T. Todd

Subjects
Cryostat, Physics, Tokamak, Mechanical Engineering, Nuclear engineering, Divertor, COMPASS-U, Solenoid, Plasma, Thermonuclear fusion, 01 natural sciences, 010305 fluids & plasmas, law.invention, Upgrade, Nuclear Energy and Engineering, Tokamak design, law, Compass, High magnetic field, 0103 physical sciences, General Materials Science, Plasma diagnostics, 010306 general physics, Civil and Structural Engineering
Abstract

COMPASS Upgrade is a new medium size, high magnetic field tokamak (R = 0.9 m, Bt = 5 T, Ip = 2 MA) currently under design in the Czech Republic. It will provide unique capabilities for addressing some of the key challenges in plasma exhaust physics, advanced confinement modes and advanced plasma configurations as well as testing new plasma facing materials and liquid metal divertor concepts. This paper contains an overview of the preliminary engineering design of the main systems of the COMPASS Upgrade tokamak (vacuum vessel, central solenoid and poloidal field coils, toroidal field coils, support structure, cryostat, cryogenic system, power supply system and machine monitoring and protection system). The description of foreseen auxiliary plasma heating systems and plasma diagnostics is also provided as well as a summary of expected plasma performance and available plasma configurations.

Published
2021

8. Interaction of candidate plasma facing materials with tokamak plasma in COMPASS

Author

Vladimír Havránek, Jukka Kolehmainen, Per Petersson, Pawel Gasior, Elzbieta Fortuna, Antti Hakola, Sanna Tervakangas, Jiří Matějíček, Anna Macková, Vladimir Weinzettl, Veronika Klevarová, D. Naydenkova, Petr Malinský, and Marek Rubel

Subjects
Physics, Nuclear and High Energy Physics, animal structures, Tokamak, COMPASS tokamak, Nuclear engineering, Analytical chemistry, Plasma, 01 natural sciences, 010305 fluids & plasmas, law.invention, Nuclear Energy and Engineering, law, Compass, 0103 physical sciences, General Materials Science, 010306 general physics
Abstract

The interaction of tokamak plasma with several materials considered for the plasma facing components of future fusion devices was studied in a small-size COMPASS tokamak. These included mainly tungsten as the prime candidate and chromium steel as an alternative whose suitability was to be assessed. For the experiments, thin coatings of tungsten, P92 steel and nickel on graphite substrates were prepared by arc-discharge sputtering. The samples were exposed to hydrogen and deuterium plasma discharges in the COMPASS tokamak in two modes: a) short exposure (several discharges) on a manipulator in the proximity of the separatrix, close to the central column, and b) long exposure (several months) at the central column, aligned with the other graphite tiles. During the discharges, standard plasma diagnostics were used and a local emission of spectral lines in the visible near ultraviolet regions, corresponding to the material erosion, was monitored. Before and after the plasma exposures, the sample surfaces were observed using scanning electron microscopy, the coatings thickness was measured using Rutherford backscattering spectroscopy, and the concentration profiles of hydrogen and deuterium were measured by elastic recoil detection analysis. The uniformity of the coatings and their thickness was verified before the exposure. After the exposure, no reduction of the thickness was observed, indicating the absence of ‘global’ erosion. Erosion was observed only in isolated spots, and attributed to unipolar arcing. Slightly larger erosion was found on the steel coatings compared to the tungsten ones. Incorporation of deuterium in a thin surface layer was observed, in dependence on the exposure mode. Additionally, boron enrichment of the long-exposure samples was observed, as a result of the tokamak chamber boronization.

Published
2017

9. Dependence on plasma shape and plasma fueling for small edge-localized mode regimes in TCV and ASDEX Upgrade

Author

V. Piergotti, F. Pesamosca, Bogdan Hnat, A. Sperduti, A. Krivska, J. Vicente, Panagiotis Tolias, Emanuele Poli, Matthias Hoelzl, Benedikt Geiger, A. Jardin, J. Ayllon-Guerola, G. Apruzzese, T. Lunt, J. Galdon-Quiroga, Riccardo Maggiora, M. Tardocchi, M. Koubiti, T. Jonsson, Bruce Lipschultz, P. Innocente, A. Gude, I Miron, M. G. Dunne, G. F. Harrer, A. Moro, A. Iantchenko, K. Galazka, P. Poloskei, K. Bogar, Roberto Ambrosino, G. Ferr, Vladimir E. Moiseenko, Istvan Cziegler, L. Guimarais, S. Vartanian, B. Erds, G. Pucella, V. Bobkov, James Buchanan, Raffaele Albanese, Harry M. Meyer, D. Boeyaert, G. F. Matthews, Eva Macusova, V. S. Marchenko, R. Zagórski, J. Buermans, A. Fil, W. Zhang, Giuseppe Gorini, B. Tal, D. Zaloga, Hugo Bufferand, A. Romano, L. Colas, J. Zebrowski, M. Weiland, L. Barrera-Orte, Matjaž Panjan, A.J. Thornton, E. Wolfrum, Miglena Dimitrova, R. M. McDermott, R. Lombroni, O. Tudisco, F. Reimold, E. R. Solano, X. Feng, Petra Bilkova, M. Groth, E. Alessi, D. S. Gahle, Olivier Février, I. Voitsekhovitch, Matthew Carr, A. Bock, O. Vasilovici, C. Ham, Lorenzo Figini, Guglielmo Rubinacci, Peter Lang, Pierre Manas, S. Costea, A. Kirk, F. Causa, J. Adamek, Vu N. M. T., M. Cavedon, O. Grover, Geert Verdoolaege, M. Spolaore, L. Sanchis-Sanchez, P. Bohm, P. V. Kazantzidis, Sarah Newton, M. Tomes, M.-L. Mayoral, J. R. Harrison, C. Mazzotta, H. Reimerdes, Jorge Morales, D. Brunetti, J. Gonzalez-Martin, Tomas Markovic, S. S. Henderson, D. Ricci, J. Juul Rasmussen, F. Janky, S. Saarelma, Z. Popovic, C. Tsironis, J. J. Rasmussen, S. K. Hansen, Sandra C. Chapman, Volker Naulin, H. Arnichand, Roberto Paccagnella, M. Faitsch, Anders Nielsen, M. Kong, V. Igochine, C. Piron, C. Bowman, Jorge Ferreira, D. Sytnykov, K. G. McClements, Olivier Sauter, Ondrej Ficker, Matthias Wiesenberger, T. Ravensbergen, C. Reux, Irena Ivanova-Stanik, Dirk Reiser, M. Bernert, M. Vallar, J-M Moret, M. Gruca, D. I. Refy, P. Cano Megias, Benoit Labit, M. Schubert, Giuliana Sias, O. Bogar, P. J. Mc Carthy, I. Faust, Gergely Papp, F. Matos, J. Garcia, C. Marini, E. L. Sorokovoy, Dimitri Voltolina, George Wilkie, J. M. Santos, R. R. Sheeba, Vladimir Weinzettl, Sergei Kasilov, J. Cerovsky, Matteo Agostini, G. Tardini, Laurie Porte, F. Dolizy, L. Gil, Matthias Komm, A. Dal Molin, B. Sieglin, Roch Kwiatkowski, M. C. C Messmer, Toke Koldborg Jensen, Vinodh Bandaru, Ben F. McMillan, Alessandra Fanni, Daniele Carnevale, Shimpei Futatani, D. P. Coster, V. Korovin, S. E. Sharapov, Patrik Ollus, J. Gath, A. Czarnecka, D. Gallart, M. Peterka, P. Vallejos Olivares, Jernej Kovacic, Nicolas Fedorczak, Silvio Ceccuzzi, L. Piron, J. Rosato, G. Kocsis, Stefan Kragh Nielsen, M. Garcia-Mu oz, Radomir Panek, S. F. Smith, Paolo Bettini, A. Mariani, R. Dejarnac, Lorenzo Frassinetti, D. Douai, L. Garzotti, H. J. Sun, C.K. Tsui, N. den Harder, John Elmerdahl Olsen, F. Bombarda, M. Francesco, Piero Martin, D. Hogeweij, P. Blanchard, F. Bouquey, Gabor Por, Luca Boncagni, Carlo Sozzi, Martin Hron, P. A. Schneider, V. P. Loschiavo, David Terranova, D. Aguiam, D. Choi, M. Gobbin, D. Iglesias, M. Reich, G. Avdeeva, A. Gallo, O. Biletskyi, M. Aradi, F. Liu, M. Griener, Antti Snicker, L. Kripner, Jérôme Bucalossi, L. Hesslow, Nick Walkden, M. Rodriguez-Ramos, T. C. Blanken, Cristian Galperti, F. Jaulmes, G. Calabr, G.A. Rattá, W. Bin, S. Garavaglia, V. Plyusnin, Andreas Frank Martitsch, A. Zisis, Rita Lorenzini, Duccio Testa, M. Passeri, Ola Embréus, N. Krawczyk, K. Särkimäki, Davide Galassi, D. Samaddar, M. Oberkofler, E. Seliunin, D. Brida, P. Buratti, F. Nabais, J. Ongena, J. Likonen, Yann Camenen, M. J. Mantsinen, F. Carpanese, S. Wiesen, P. Piovesan, Mirko Salewski, J. Hawke, Florian Laggner, R. Bilato, M. Wischmeier, L. Pigatto, G. I. Pokol, G. Giruzzi, Jens Madsen, D. Gadariya, L. Stipani, Christian Theiler, J. Stober, Michael Barnes, Timothy Goodman, R. D. Nem, J. J. Dominguez-Palacios Duran, F. Militello, Y. Kulyk, D. J. Cruz Zabala, A. Drenik, P. Manz, M. Scheffer, V. Pericoli Radolfini, B. Tilia, John Omotani, B. Vanovac, B. S. Schneider, E. Fable, Jakub Urban, T. Gyergyek, A. N. Karpushov, M. Farnik, Jakub Seidl, Christopher G. Albert, Antoine Merle, A. Cathey, D. A. Ryan, Sergio Galeani, R. Scannell, A. Havranek, G. de Carolis, C. Soria-Hoyo, S. Gibson, D. Carralero, D. Meshcheriakov, Morten Stejner, B. P. Duval, Francesco Cordella, Mitja Kelemen, Svetlana V. Ratynskaia, Stefano Coda, L. Calacci, C. Cianfarani, Faa Federico Felici, A. C. A. Figueiredo, L. Panaccione, E. Viezzer, Fabio Villone, Daniele Milanesio, Winfried Kernbichler, Mario Sassano, A. Teplukhina, S. Zoletnik, L. Laguardia, P. Molina Cabrera, Taina Kurki-Suonio, D. Micheletti, P. Zanca, Daniel Dunai, S. Feng, J. Decker, Stylianos Varoutis, Lorella Carraro, M. Wensing, Gustavo Granucci, Artur Palha, A. Kappatou, J. Garcia-Lopez, Felix I. Parra, Ye. O. Kazakov, S. Brezinsek, Didier Mazon, A. Lahtinen, I. Paradela Perez, P. Chmielewski, L. Giacomelli, Alessandro Pau, Gianluca Spizzo, R. Delogu, R. J. Akers, H. De Oliveira, Petr Vondracek, F. P. Orsitto, J. Hobirk, L. Xiang, A. Burckhart, B. Maljaars, V. Petrzilka, Ocleto D'Arcangelo, P. David, D. Grekov, Tamás Szepesi, Y. Andr be, P. Hacek, M. Toscano-Jimenez, T. Pütterich, L. Cordaro, V. Nikolaeva, F. Orain, M. Rabinski, C. Ionita-Schrittwieser, T. Tala, Maria Ester Puiatti, A. Casolari, T. Happel, Pär Strand, Benjamin Daniel Dudson, P. Mantica, Z. Huang, D. Colette, G. Ciraolo, Jan Mlynar, W. Suttrop, C. Meineri, J. Horacek, Seppo Sipilä, M. Gospodarczyk, S. Mastrostefano, Jesús Vega, Antti Hakola, Kevin Verhaegh, Roman Schrittwieser, C. Marchetto, M. Willensdorfer, Jari Varje, D. C. van Vugt, J. Faustin, Mathias Hoppe, M. Dreval, A. Perek, C. Angioni, Laure Vermare, U. A. Sheikh, J. F. Rivero-Rodriguez, G. Rubino, S.N. Reznik, Tsv K Popov, S. Nowak, A. S. Jacobsen, J. R. Martin Solis, David Moulton, Heinz Isliker, K. Wu, Anna Salmi, F. Nespoli, S. Elmore, O. Kudlacek, A. Kallenbach, Rok Zaplotnik, D. L. Keeling, L. Giannone, M. Maraschek, Carlos B. da Silva, F. Hitzler, M. Valovic, M. W. Jakubowski, L. Gabellieri, Jozef Varju, Marco Cecconello, M. Valisa, Vlado Menkovski, Gábor Cseh, E. Thoren, T. Eich, R. Coelho, F. Bagnato, Matteo Zuin, Alexander Kendl, G. Rocchi, G. Pautasso, D. Naydenkova, R. O. Pavlichenko, M. Fontana, Lionello Marrelli, Tommaso Bolzonella, Nicola Vianello, Pascale Hennequin, R. Ochoukov, Tom Wauters, Christian Hopf, Ch. Fuchs, E. Giovannozzi, Fulvio Auriemma, Roberto Maurizio, Stefan Buller, Massimo Nocente, K. Krieger, G. Grenfell, N. Rispoli, R. Dux, Barbara Cannas, Laboratoire de Physique des Plasmas (LPP), Université Paris-Saclay-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11)-École polytechnique (X)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Labit, B., Eich, T., Harrer, G. F., Wolfrum, E., Bernert, M., Dunne, M. G., Frassinetti, L., Hennequin, P., Maurizio, R., Merle, A., Meyer, H., Saarelma, S., Sheikh, U., Adamek, J., Agostini, M., Aguiam, D., Akers, R., Albanese, R., Albert, C., Alessi, E., Ambrosino, R., Andr be, Y., Angioni, C., Apruzzese, G., Aradi, M., Arnichand, H., Auriemma, F., Avdeeva, G., Ayllon-Guerola, J. M., Bagnato, F., Bandaru, V. K., Barnes, M., Barrera-Orte, L., Bettini, P., Bilato, R., Biletskyi, O., Bilkova, P., Bin, W., Blanchard, P., Blanken, T., Bobkov, V., Bock, A., Boeyaert, D., Bogar, K., Bogar, O., Bohm, P., Bolzonella, T., Bombarda, F., Boncagni, L., Bouquey, F., Bowman, C., Brezinsek, S., Brida, D., Brunetti, D., Bucalossi, J., Buchanan, J., Buermans, J., Bufferand, H., Buller, S., Buratti, P., Burckhart, A., Calabr, G., Calacci, L., Camenen, Y., Cannas, B., Cano Megias, P., Carnevale, D., Carpanese, F., Carr, M., Carralero, D., Carraro, L., Casolari, A., Cathey, A., Causa, F., Cavedon, M., Cecconello, M., Ceccuzzi, S., Cerovsky, J., Chapman, S., Chmielewski, P., Choi, D., Cianfarani, C., Ciraolo, G., Coda, S., Coelho, R., Colas, L., Colette, D., Cordaro, L., Cordella, F., Costea, S., Coster, D., Cruz Zabala, D. J., Cseh, G., Czarnecka, A., Cziegler, I., D'Arcangelo, O., Dal Molin, A., David, P., De Carolis, G., De Oliveira, H., Decker, J., Dejarnac, R., Delogu, R., Den Harder, N., Dimitrova, M., Dolizy, F., Dominguez-Palacios Duran, J. J., Douai, D., Drenik, A., Dreval, M., Dudson, B., Dunai, D., Duval, B. P., Dux, R., Elmore, S., Embreus, O., Erds, B., Fable, E., Faitsch, M., Fanni, A., Farnik, M., Faust, I., Faustin, J., Fedorczak, N., Felici, F., Feng, S., Feng, X., Ferreira, J., Ferr, G., Fevrier, O., Ficker, O., Figini, L., Figueiredo, A., Fil, A., Fontana, M., Francesco, M., Fuchs, C., Futatani, S., Gabellieri, L., Gadariya, D., Gahle, D., Galassi, D., Galazka, K., Galdon-Quiroga, J., Galeani, S., Gallart, D., Gallo, A., Galperti, C., Garavaglia, S., Garcia, J., Garcia-Lopez, J., Garcia-Mu oz, M., Garzotti, L., Gath, J., Geiger, B., Giacomelli, L., Giannone, L., Gibson, S., Gil, L., Giovannozzi, E., Giruzzi, G., Gobbin, M., Gonzalez-Martin, J., Goodman, T. P., Gorini, G., Gospodarczyk, M., Granucci, G., Grekov, D., Grenfell, G., Griener, M., Groth, M., Grover, O., Gruca, M., Gude, A., Guimarais, L., Gyergyek, T., Hacek, P., Hakola, A., Ham, C., Happel, T., Harrison, J., Havranek, A., Hawke, J., Henderson, S., Hesslow, L., Hitzler, F., Hnat, B., Hobirk, J., Hoelzl, M., Hogeweij, D., Hopf, C., Hoppe, M., Horacek, J., Hron, M., Huang, Z., Iantchenko, A., Iglesias, D., Igochine, V., Innocente, P., Ionita-Schrittwieser, C., Isliker, H., Ivanova-Stanik, I., Jacobsen, A., Jakubowski, M., Janky, F., Jardin, A., Jaulmes, F., Jensen, T., Jonsson, T., Kallenbach, A., Kappatou, A., Karpushov, A., Kasilov, S., Kazakov, Y., Kazantzidis, P. V., Keeling, D., Kelemen, M., Kendl, A., Kernbichler, W., Kirk, A., Kocsis, G., Komm, M., Kong, M., Korovin, V., Koubiti, M., Kovacic, J., Krawczyk, N., Krieger, K., Kripner, L., Krivska, A., Kudlacek, O., Kulyk, Y., Kurki-Suonio, T., Kwiatkowski, R., Laggner, F., Laguardia, L., Lahtinen, A., Lang, P., Likonen, J., Lipschultz, B., Liu, F., Lombroni, R., Lorenzini, R., Loschiavo, V. P., Lunt, T., Macusova, E., Madsen, J., Maggiora, R., Maljaars, B., Manas, P., Mantica, P., Mantsinen, M. J., Manz, P., Maraschek, M., Marchenko, V., Marchetto, C., Mariani, A., Marini, C., Markovic, T., Marrelli, L., Martin, P., Martin Solis, J. R., Martitsch, A., Mastrostefano, S., Matos, F., Matthews, G., Mayoral, M. -L., Mazon, D., Mazzotta, C., Mc Carthy, P., Mcclements, K., Mcdermott, R., Mcmillan, B., Meineri, C., Menkovski, V., Meshcheriakov, D., Messmer, M., Micheletti, D., Milanesio, D., Militello, F., Miron, I. G., Mlynar, J., Moiseenko, V., Molina Cabrera, P. A., Morales, J., Moret, J. -M., Moro, A., Moulton, D., Nabais, F., Naulin, V., Naydenkova, D., Nem, R. D., Nespoli, F., Newton, S., Nielsen, A. H., Nielsen, S. K., Nikolaeva, V., Nocente, M., Nowak, S., Oberkofler, M., Ochoukov, R., Ollus, P., Olsen, J., Omotani, J., Ongena, J., Orain, F., Orsitto, F. P., Paccagnella, R., Palha, A., Panaccione, L., Panek, R., Panjan, M., Papp, G., Paradela Perez, I., Parra, F., Passeri, M., Pau, A., Pautasso, G., Pavlichenko, R., Perek, A., Pericoli Radolfini, V., Pesamosca, F., Peterka, M., Petrzilka, V., Piergotti, V., Pigatto, L., Piovesan, P., Piron, C., Piron, L., Plyusnin, V., Pokol, G., Poli, E., Poloskei, P., Popov, T., Popovic, Z., Por, G., Porte, L., Pucella, G., Puiatti, M. E., Putterich, T., Rabinski, M., Juul Rasmussen, J., Rasmussen, J., Ratta, G. A., Ratynskaia, S., Ravensbergen, T., Refy, D., Reich, M., Reimerdes, H., Reimold, F., Reiser, D., Reux, C., Reznik, S., Ricci, D., Rispoli, N., Rivero-Rodriguez, J. F., Rocchi, G., Rodriguez-Ramos, M., Romano, A., Rosato, J., Rubinacci, G., Rubino, G., Ryan, D. A., Salewski, M., Salmi, A., Samaddar, D., Sanchis-Sanchez, L., Santos, J., Sarkimaki, K., Sassano, M., Sauter, O., Scannell, R., Scheffer, M., Schneider, B. S., Schneider, P., Schrittwieser, R., Schubert, M., Seidl, J., Seliunin, E., Sharapov, S., Sheeba, R. R., Sias, G., Sieglin, B., Silva, C., Sipila, S., Smith, S., Snicker, A., Solano, E. R., Hansen, S. K., Soria-Hoyo, C., Sorokovoy, E., Sozzi, C., Sperduti, A., Spizzo, G., Spolaore, M., Stejner, M., Stipani, L., Stober, J., Strand, P., Sun, H., Suttrop, W., Sytnykov, D., Szepesi, T., Tal, B., Tala, T., Tardini, G., Tardocchi, M., Teplukhina, A., Terranova, D., Testa, D., Theiler, C., Thoren, E., Thornton, A., Tilia, B., Tolias, P., Tomes, M., Toscano-Jimenez, M., Tsironis, C., Tsui, C., Tudisco, O., Urban, J., Valisa, M., Vallar, M., Vallejos Olivares, P., Valovic, M., Van Vugt, D., Vanovac, B., Varje, J., Varju, J., Varoutis, S., Vartanian, S., Vasilovici, O., Vega, J., Verdoolaege, G., Verhaegh, K., Vermare, L., Vianello, N., Vicente, J., Viezzer, E., Villone, F., Voitsekhovitch, I., Voltolina, D., Vondracek, P., Vu, N. M. T., Walkden, N., Wauters, T., Weiland, M., Weinzettl, V., Wensing, M., Wiesen, S., Wiesenberger, M., Wilkie, G., Willensdorfer, M., Wischmeier, M., Wu, K., Xiang, L., Zagorski, R., Zaloga, D., Zanca, P., Zaplotnik, R., Zebrowski, J., Zhang, W., Zisis, A., Zoletnik, S., Zuin, M., Swiss Federal Institute of Technology Lausanne, Max-Planck-Institut für Plasmaphysik, Vienna University of Technology, KTH Royal Institute of Technology, Université Paris-Saclay, JET, Czech Academy of Sciences, National Research Council of Italy, University of Lisbon, University of Naples Federico II, Graz University of Technology, University of Naples Parthenope, Agenzia nazionale per le nuove tecnologie, l'energia e lo sviluppo economico sostenibile, Danmarks Tekniske Universitet, University of Seville, University of Oxford, EUROfusion Programme Management Unit, National Science Center Kharkov Institute of Physics and Technology, Eindhoven University of Technology, Forschungszentrum Jülich, CEA, University of York, Royal Military Academy, Chalmers University of Technology, Tuscia University, Università di Roma Tor Vergata, CNRS, University of Cagliari, CIEMAT, Uppsala University, University of Warwick, Soltan Institute for Nuclear Studies, University of Innsbruck, Hungarian Academy of Sciences, Budapest University of Technology and Economics, Durham University, BarcelonaTech, University of Strathclyde, Barcelona Supercomputing Center, University of Milan - Bicocca, Karlsruhe Institute of Technology, Fusion and Plasma Physics, J. Stefan Institute, VTT Technical Research Centre of Finland, Dutch Institute for Fundamental Energy Research, Aristotle University of Thessaloniki, National Technical University of Athens, National Centre for Nuclear Research, University of Helsinki, Université Côte d'Azur, Polytechnic University of Turin, NASU - Institute of Nuclear Research, University of Cassino and Southern Lazio, University College Cork, National Institute for Laser, Plasma and Radiation Physics, Department of Applied Physics, Sofia University St. Kliment Ohridski, Ghent University, Aalto-yliopisto, Aalto University, Labit, B, Eich, T, Harrer, G, Wolfrum, E, Bernert, M, Dunne, M, Frassinetti, L, Hennequin, P, Maurizio, R, Merle, A, Meyer, H, Saarelma, S, Sheikh, U, Adamek, J, Agostini, M, Aguiam, D, Akers, R, Albanese, R, Albert, C, Alessi, E, Ambrosino, R, Andr be, Y, Angioni, C, Apruzzese, G, Aradi, M, Arnichand, H, Auriemma, F, Avdeeva, G, Ayllon-Guerola, J, Bagnato, F, Bandaru, V, Barnes, M, Barrera-Orte, L, Bettini, P, Bilato, R, Biletskyi, O, Bilkova, P, Bin, W, Blanchard, P, Blanken, T, Bobkov, V, Bock, A, Boeyaert, D, Bogar, K, Bogar, O, Bohm, P, Bolzonella, T, Bombarda, F, Boncagni, L, Bouquey, F, Bowman, C, Brezinsek, S, Brida, D, Brunetti, D, Bucalossi, J, Buchanan, J, Buermans, J, Bufferand, H, Buller, S, Buratti, P, Burckhart, A, Calabr, G, Calacci, L, Camenen, Y, Cannas, B, Cano Megias, P, Carnevale, D, Carpanese, F, Carr, M, Carralero, D, Carraro, L, Casolari, A, Cathey, A, Causa, F, Cavedon, M, Cecconello, M, Ceccuzzi, S, Cerovsky, J, Chapman, S, Chmielewski, P, Choi, D, Cianfarani, C, Ciraolo, G, Coda, S, Coelho, R, Colas, L, Colette, D, Cordaro, L, Cordella, F, Costea, S, Coster, D, Cruz Zabala, D, Cseh, G, Czarnecka, A, Cziegler, I, D'Arcangelo, O, Dal Molin, A, David, P, De Carolis, G, De Oliveira, H, Decker, J, Dejarnac, R, Delogu, R, Den Harder, N, Dimitrova, M, Dolizy, F, Dominguez-Palacios Duran, J, Douai, D, Drenik, A, Dreval, M, Dudson, B, Dunai, D, Duval, B, Dux, R, Elmore, S, Embreus, O, Erds, B, Fable, E, Faitsch, M, Fanni, A, Farnik, M, Faust, I, Faustin, J, Fedorczak, N, Felici, F, Feng, S, Feng, X, Ferreira, J, Ferr, G, Fevrier, O, Ficker, O, Figini, L, Figueiredo, A, Fil, A, Fontana, M, Francesco, M, Fuchs, C, Futatani, S, Gabellieri, L, Gadariya, D, Gahle, D, Galassi, D, Galazka, K, Galdon-Quiroga, J, Galeani, S, Gallart, D, Gallo, A, Galperti, C, Garavaglia, S, Garcia, J, Garcia-Lopez, J, Garcia-Mu oz, M, Garzotti, L, Gath, J, Geiger, B, Giacomelli, L, Giannone, L, Gibson, S, Gil, L, Giovannozzi, E, Giruzzi, G, Gobbin, M, Gonzalez-Martin, J, Goodman, T, Gorini, G, Gospodarczyk, M, Granucci, G, Grekov, D, Grenfell, G, Griener, M, Groth, M, Grover, O, Gruca, M, Gude, A, Guimarais, L, Gyergyek, T, Hacek, P, Hakola, A, Ham, C, Happel, T, Harrison, J, Havranek, A, Hawke, J, Henderson, S, Hesslow, L, Hitzler, F, Hnat, B, Hobirk, J, Hoelzl, M, Hogeweij, D, Hopf, C, Hoppe, M, Horacek, J, Hron, M, Huang, Z, Iantchenko, A, Iglesias, D, Igochine, V, Innocente, P, Ionita-Schrittwieser, C, Isliker, H, Ivanova-Stanik, I, Jacobsen, A, Jakubowski, M, Janky, F, Jardin, A, Jaulmes, F, Jensen, T, Jonsson, T, Kallenbach, A, Kappatou, A, Karpushov, A, Kasilov, S, Kazakov, Y, Kazantzidis, P, Keeling, D, Kelemen, M, Kendl, A, Kernbichler, W, Kirk, A, Kocsis, G, Komm, M, Kong, M, Korovin, V, Koubiti, M, Kovacic, J, Krawczyk, N, Krieger, K, Kripner, L, Krivska, A, Kudlacek, O, Kulyk, Y, Kurki-Suonio, T, Kwiatkowski, R, Laggner, F, Laguardia, L, Lahtinen, A, Lang, P, Likonen, J, Lipschultz, B, Liu, F, Lombroni, R, Lorenzini, R, Loschiavo, V, Lunt, T, Macusova, E, Madsen, J, Maggiora, R, Maljaars, B, Manas, P, Mantica, P, Mantsinen, M, Manz, P, Maraschek, M, Marchenko, V, Marchetto, C, Mariani, A, Marini, C, Markovic, T, Marrelli, L, Martin, P, Martin Solis, J, Martitsch, A, Mastrostefano, S, Matos, F, Matthews, G, Mayoral, M, Mazon, D, Mazzotta, C, Mc Carthy, P, Mcclements, K, Mcdermott, R, Mcmillan, B, Meineri, C, Menkovski, V, Meshcheriakov, D, Messmer, M, Micheletti, D, Milanesio, D, Militello, F, Miron, I, Mlynar, J, Moiseenko, V, Molina Cabrera, P, Morales, J, Moret, J, Moro, A, Moulton, D, Nabais, F, Naulin, V, Naydenkova, D, Nem, R, Nespoli, F, Newton, S, Nielsen, A, Nielsen, S, Nikolaeva, V, Nocente, M, Nowak, S, Oberkofler, M, Ochoukov, R, Ollus, P, Olsen, J, Omotani, J, Ongena, J, Orain, F, Orsitto, F, Paccagnella, R, Palha, A, Panaccione, L, Panek, R, Panjan, M, Papp, G, Paradela Perez, I, Parra, F, Passeri, M, Pau, A, Pautasso, G, Pavlichenko, R, Perek, A, Pericoli Radolfini, V, Pesamosca, F, Peterka, M, Petrzilka, V, Piergotti, V, Pigatto, L, Piovesan, P, Piron, C, Piron, L, Plyusnin, V, Pokol, G, Poli, E, Poloskei, P, Popov, T, Popovic, Z, Por, G, Porte, L, Pucella, G, Puiatti, M, Putterich, T, Rabinski, M, Juul Rasmussen, J, Rasmussen, J, Ratta, G, Ratynskaia, S, Ravensbergen, T, Refy, D, Reich, M, Reimerdes, H, Reimold, F, Reiser, D, Reux, C, Reznik, S, Ricci, D, Rispoli, N, Rivero-Rodriguez, J, Rocchi, G, Rodriguez-Ramos, M, Romano, A, Rosato, J, Rubinacci, G, Rubino, G, Ryan, D, Salewski, M, Salmi, A, Samaddar, D, Sanchis-Sanchez, L, Santos, J, Sarkimaki, K, Sassano, M, Sauter, O, Scannell, R, Scheffer, M, Schneider, B, Schneider, P, Schrittwieser, R, Schubert, M, Seidl, J, Seliunin, E, Sharapov, S, Sheeba, R, Sias, G, Sieglin, B, Silva, C, Sipila, S, Smith, S, Snicker, A, Solano, E, Hansen, S, Soria-Hoyo, C, Sorokovoy, E, Sozzi, C, Sperduti, A, Spizzo, G, Spolaore, M, Stejner, M, Stipani, L, Stober, J, Strand, P, Sun, H, Suttrop, W, Sytnykov, D, Szepesi, T, Tal, B, Tala, T, Tardini, G, Tardocchi, M, Teplukhina, A, Terranova, D, Testa, D, Theiler, C, Thoren, E, Thornton, A, Tilia, B, Tolias, P, Tomes, M, Toscano-Jimenez, M, Tsironis, C, Tsui, C, Tudisco, O, Urban, J, Valisa, M, Vallar, M, Vallejos Olivares, P, Valovic, M, Van Vugt, D, Vanovac, B, Varje, J, Varju, J, Varoutis, S, Vartanian, S, Vasilovici, O, Vega, J, Verdoolaege, G, Verhaegh, K, Vermare, L, Vianello, N, Vicente, J, Viezzer, E, Villone, F, Voitsekhovitch, I, Voltolina, D, Vondracek, P, Vu, N, Walkden, N, Wauters, T, Weiland, M, Weinzettl, V, Wensing, M, Wiesen, S, Wiesenberger, M, Wilkie, G, Willensdorfer, M, Wischmeier, M, Wu, K, Xiang, L, Zagorski, R, Zaloga, D, Zanca, P, Zaplotnik, R, Zebrowski, J, Zhang, W, Zisis, A, Zoletnik, S, Zuin, M, Universitat Politècnica de Catalunya. Departament de Física, Universitat Politècnica de Catalunya. ANT - Advanced Nuclear Technologies Research Group, Control Systems Technology, Science and Technology of Nuclear Fusion, Data Mining, Sensorics for fusion reactors, and Magneto-Hydro-Dynamic Stability of Fusion Plasmas

Subjects
Nuclear and High Energy Physics, Settore ING-INF/04, Work package, grassy ELM, ballooning modes, Nuclear physics, 01 natural sciences, Flattening, Ballooning, 010305 fluids & plasmas, grassy ELMs, separatrix density, ASDEX Upgrade, [PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], 0103 physical sciences, 010306 general physics, Edge-localized mode, QC, H-mode, plasma triangularity, type-II ELMs, Physics, Física [Àrees temàtiques de la UPC], type-II ELM, Plasma, Condensed Matter Physics, Null (physics), Shear (sheet metal), Física nuclear, Atomic physics, ballooning mode
Abstract

Within the EUROfusion MST1 work package, a series of experiments has been conducted on AUG and TCV devices to disentangle the role of plasma fueling and plasma shape for the onset of small ELM regimes. On both devices, small ELM regimes with high confinement are achieved if and only if two conditions are fulfilled at the same time. Firstly, the plasma density at the separatrix must be large enough (), leading to a pressure profile flattening at the separatrix, which stabilizes type-I ELMs. Secondly, the magnetic configuration has to be close to a double null (DN), leading to a reduction of the magnetic shear in the extreme vicinity of the separatrix. As a consequence, its stabilizing effect on ballooning modes is weakened. Peer Reviewed Article escrit per 365 autors/autores: Labit, B.; Eich, T.; Harrer, G. F.; Wolfrum, E.; Bernert, M.; Dunne, M. G.; Frassinetti, L.; Hennequin, P.; Maurizio, R.; Merle, A.; Meyer, H.; Saarelma, S.; Sheikh, U.; Adamek, J.; Agostini, M.; Aguiam, D.; Akers, R.; Albanese, R.; Albert, C.; Alessi, E.; Ambrosino, R.; Andr be, Y.; Angioni, C.; Apruzzese, G.; Aradi, M.; Arnichand, H.; Auriemma, F.; Avdeeva, G.; Ayllon-Guerola, J. M.; Bagnato, F.; Bandaru, V. K.; Barnes, M.; Barrera-Orte, L.; Bettini, P.; Bilato, R.; Biletskyi, O.; Bilkova, P.; Bin, W.; Blanchard, P.; Blanken, T.; Bobkov, V.; Bock, A.; Boeyaert, D.; Bogar, K.; Bogar, O.; Bohm, P.; Bolzonella, T.; Bombarda, F.; Boncagni, L.; Bouquey, F.; Bowman, C.; Brezinsek, S.; Brida, D.; Brunetti, D.; Bucalossi, J.; Buchanan, J.; Buermans, J.; Bufferand, H.; Buller, S.; Buratti, P.; Burckhart, A.; Calabr, G.; Calacci, L.; Camenen, Y.; Cannas, B.; Cano Megías, P.; Carnevale, D.; Carpanese, F.; Carr, M.; Carralero, D.; Carraro, L.; Casolari, A.; Cathey, A.; Causa, F.; Cavedon, M.; Cecconello, M.; Ceccuzzi, S.; Cerovsky, J.; Chapman, S.; Chmielewski, P.; Choi, D.; Cianfarani, C.; Ciraolo, G.; Coda, S.; Coelho, R.; Colas, L.; Colette, D.; Cordaro, L.; Cordella, F.; Costea, S.; Coster, D.; Cruz Zabala, D. J.; Cseh, G.; Czarnecka, A.; Cziegler, I.; D’Arcangelo, O.; Dal Molin, A.; David, P.; De Carolis, G.; De Oliveira, H.; Decker, J.; Dejarnac, R.; Delogu, R.; Den Harder, N.; Dimitrova, M.; Dolizy, F.; Domínguez-Palacios Durán, J. J.; Douai, D.; Drenik, A.; Dreval, M.; Dudson, B.; Dunai, D.; Duval, B. P.; Dux, R.; Elmore, S.; Embréus, O.; Erds, B.; Fable, E.; Faitsch, M.; Fanni, A.; Farnik, M.; Faust, I.; Faustin, J.; Fedorczak, N.; Felici, F.; Feng, S.; Feng, X.; Ferreira, J.; Ferr, G.; Février, O.; Ficker, O.; Figini, L.; Figueiredo, A.; Fil, A.; Fontana, M.; Francesco, M.; Fuchs, C.; Futatani, S.; Gabellieri, L.; Gadariya, D.; Gahle, D.; Galassi, D.; Gałązka, K.; Galdon-Quiroga, J.; Galeani, S.; Gallart, D.; Gallo, A.; Galperti, C.; Garavaglia, S.; Garcia, J.; Garcia-Lopez, J.; Garcia-Mu oz, M.; Garzotti, L.; Gath, J.; Geiger, B.; Giacomelli, L.; Giannone, L.; Gibson, S.; Gil, L.; Giovannozzi, E.; Giruzzi, G.; Gobbin, M.; Gonzalez-Martin, J.; Goodman, T. P.; Gorini, G.; Gospodarczyk, M.; Granucci, G.; Grekov, D. 1; Grenfell, G.; Griener, M.; Groth, M.; Grover, O.; Gruca, M.; Gude, A.; Guimarais, L.; Gyergyek, T.; Hacek, P.; Hakola, A.; Ham, C.; Happel, T.; Harrison, J.; Havranek, A.; Hawke, J.; Henderson, S.; Hesslow, L.; Hitzler, F.; Hnat, B.; Hobirk, J.; Hoelzl, M.; Hogeweij, D.; Hopf, C.; Hoppe, M.; Horacek, J.; Hron, M.; Huang, Z.; Iantchenko, A.; Iglesias, D.; Igochine, V.; Innocente, P.; Ionita-Schrittwieser, C.; Isliker, H.; Ivanova-Stanik, I.; Jacobsen, A.; Jakubowski, M.; Janky, F.; Jardin, A.; Jaulmes, F.; Jensen, T.; Jonsson, T.; Kallenbach, A.; Kappatou, A.; Karpushov, A.; Kasilov, S.; Kazakov, Y.; Kazantzidis, P. V.; Keeling, D.; Kelemen, M.; Kendl, A.; Kernbichler, W.; Kirk, A.; Kocsis, G.; Komm, M.; Kong, M.; Korovin, V.; Koubiti, M.; Kovacic, J.; Krawczyk, N.; Krieger, K.; Kripner, L.; Křivská, A.; Kudlacek, O.; Kulyk, Y.; Kurki-Suonio, T.; Kwiatkowski, R.; Laggner, F.; Laguardia, L.; Lahtinen, A.; Lang, P.; Likonen, J.; Lipschultz, B.; Liu, F.; Lombroni, R.; Lorenzini, R.; Loschiavo, V. P.; Lunt, T.; MacUsova, E.; Madsen, J.; Maggiora, R.; Maljaars, B.; Manas, P.; Mantica, P.; Mantsinen, M. J.; Manz, P.; Maraschek, M.; Marchenko, V.; Marchetto, C.; Mariani, A.; Marini, C.; Markovic, T.; Marrelli, L.; Martin, P.; Martín Solís, J. R.; Martitsch, A.; Mastrostefano, S.; Matos, F.; Matthews, G.; Mayoral, M.-L.; Mazon, D.; Mazzotta, C.; Mc Carthy, P.; McClements, K.; McDermott, R.; McMillan, B.; Meineri, C.; Menkovski, V.; Meshcheriakov, D.; Messmer, M.; Micheletti, D.; Milanesio, D.; Militello, F.; Miron, I. G.; Mlynar, J.; Moiseenko, V.; Molina Cabrera, P. A.; Morales, J.; Moret, J.-M.; Moro, A.; Moulton, D.; Nabais, F.; Naulin, V.; Naydenkova, D.; Nem, R. D.; Nespoli, F.; Newton, S.; Nielsen, A. H.; Nielsen, S. K.; Nikolaeva, V.; Nocente, M.; Nowak, S.; Oberkofler, M.; Ochoukov, R.; Ollus, P.; Olsen, J.; Omotani, J.; Ongena, J.; Orain, F.; Orsitto, F. P.; Paccagnella, R.; Palha, A.; Panaccione, L.; Panek, R.; Panjan, M.; Papp, G.; Paradela Perez, I.; Parra, F.; Passeri, M.; Pau, A.; Pautasso, G.; Pavlichenko, R.; Perek, A.; Pericoli Radolfini, V.; Pesamosca, F.; Peterka, M.; Petrzilka, V.; Piergotti, V.; Pigatto, L.; Piovesan, P.; Piron, C.; Piron, L.; Plyusnin, V.; Pokol, G.; Poli, E.; Pölöskei, P.; Popov, T.; Popovic, Z.; Pór, G.; Porte, L.; Pucella, G.; Puiatti, M. E.; Pütterich, T.; Rabinski, M.; Juul Rasmussen, J.; Rasmussen, J.; Rattá, G. A.; Ratynskaia, S.; Ravensbergen, T.; Réfy, D.; Reich, M.; Reimerdes, H.; Reimold, F.; Reiser, D.; Reux, C.; Reznik, S.; Ricci, D.; Rispoli, N.; Rivero-Rodriguez, J. F.; Rocchi, G.; Rodriguez-Ramos, M.; Romano, A.; Rosato, J.; Rubinacci, G.; Rubino, G.; Ryan, D. A.; Salewski, M.; Salmi, A.; Samaddar, D.; Sanchis-Sanchez, L.; Santos, J.; Särkimäki, K.; Sassano, M.; Sauter, O.; Scannell, R.; Scheffer, M.; Schneider, B. S.; Schneider, P.; Schrittwieser, R.; Schubert, M.; Seidl, J.; Seliunin, E.; Sharapov, S.; Sheeba, R. R.; Sias, G.; Sieglin, B.; Silva, C.; Sipilä, S.; Smith, S.; Snicker, A.; Solano, E. R.; Hansen, S. K.; Soria-Hoyo, C.; Sorokovoy, E.; Sozzi, C.; Sperduti, A.; Spizzo, G.; Spolaore, M.; Stejner, M.; Stipani, L.; Stober, J.; Strand, P.; Sun, H.; Suttrop, W.; Sytnykov, D.; Szepesi, T.; Tál, B.; Tala, T.; Tardini, G.; Tardocchi, M.; Teplukhina, A.; Terranova, D.; Testa, D.; Theiler, C.; Thorén, E.; Thornton, A.; Tilia, B.; Tolias, P.; Tomes, M.; Toscano-Jimenez, M.; Tsironis, C.; Tsui, C.; Tudisco, O.; Urban, J.; Valisa, M.; Vallar, M.; Vallejos Olivares, P.; Valovic, M.; Van Vugt, D.; Vanovac, B.; Varje, J.; Varju, J.; Varoutis, S. 1; Vartanian, S.; Vasilovici, O.; Vega, J.; Verdoolaege, G.; Verhaegh, K.; Vermare, L.; Vianello, N.; Vicente, J.; Viezzer, E.; Villone, F.; Voitsekhovitch, I.; Voltolina, D.; Vondracek, P.; Vu, N. M. T.; Walkden, N.; Wauters, T.; Weiland, M.; Weinzettl, V.; Wensing, M.; Wiesen, S.; Wiesenberger, M.; Wilkie, G.; Willensdorfer, M.; Wischmeier, M.; Wu, K.; Xiang, L.; Zagorski, R.; Zaloga, D.; Zanca, P.; Zaplotnik, R.; Zebrowski, J.; Zhang, W.; Zisis, A.; Zoletnik, S.; Zuin, M.

Published
2019

10. Runaway electron beam stability and decay in COMPASS

Author

M. Vlainic, A. Casolari, Petr Kulhánek, Josef Havlicek, D. Naydenkova, Petr Vondracek, Tomas Markovic, Compass Team, M. Rabinski, Y. Peysson, Martin Imrisek, Daniele Carnevale, J. Krbec, Marco Gobbin, A. Havranek, M. Gospodarczyk, C. Reux, Ondrej Ficker, Radomir Panek, Vaclav Vrba, Eva Macusova, Jakub Urban, Gergely Papp, David Bren, Vladimír Linhart, Jan Mlynar, V.V. Plyusnin, Vladimir Weinzettl, M. Farnik, M. Jerab, J. Cerovsky, Martin Hron, M. Sos, O. Grover, Jozef Varju, V. Svoboda, M. Marcisovsky, Peter Svihra, M. Tomes, J. Decker, COMPASS Team, and EUROfusion MST1 Team

Subjects
Nuclear and High Energy Physics, Settore ING-INF/04, Tokamak, chemistry.chemical_element, Electron, Effective radiated power, tomography, disruptions, 7. Clean energy, 01 natural sciences, 010305 fluids & plasmas, law.invention, Neon, law, 0103 physical sciences, 010306 general physics, Physics, Argon, COMPASS tokamak, runaway electrons, Plasma, Condensed Matter Physics, Computational physics, chemistry, tokamaks, Beam (structure)
Abstract

This paper presents two scenarios used for generation of a runaway electron (RE) beam in the COMPASS tokamak with a focus on the decay phase and control of the beam. The first scenario consists of massive gas injection of argon into the current ramp-up phase, leading to a disruption accompanied by runaway plateau generation. In the second scenario, injection of a smaller amount of gas is used in order to isolate the RE beam from high-temperature plasma. The performances of current control and radial and vertical position feedback control in the second scenario were experimentally studied and analysed. The role of RE energy in the radial position stability of the RE beam seems to be crucial. A comparison of the decay phase of the RE beam in various amounts of Ar or Ne was studied using absolute extreme ultraviolet (AXUV) tomography and hard x-ray (HXR) intensity measurement. Argon clearly leads to higher HXR fluxes for the same current decay rate than neon, while radiated power based on AXUV measurements is larger for Ne in the same set of discharges.

Published
2019

11. Runaway electron experiments at COMPASS in support of the EUROfusion ITER physics research

Author

Eva Macusova, E. Matveeva, Jan Mlynar, Jozef Varju, Daniele Carnevale, Josef Havlicek, J. Cerovsky, D. Naydenkova, David Bren, Marco Gobbin, Gergely Papp, Petr Vondracek, M. Farnik, M. Rabinski, P Kulhanek, Martin Imrisek, O. Bogar, M. Marcisovsky, M. Vlainic, Martin Hron, M. Jakubowski, V. Svoboda, Ondrej Ficker, Radomir Panek, J. Zebrowski, Peter Svihra, Vladimír Linhart, V.V. Plyusnin, N. Lamas, A. Casolari, Tomas Markovic, Vladimir Weinzettl, Jakub Urban, A. Havranek, Karol Malinowski, M. Gospodarczyk, COMPASS Team, and EUROfusion MST1 Team

Subjects
Physics, Light nucleus, Tokamak, Nuclear engineering, Iter tokamak, runaway electrons, RMP, Plasma confinement, Electron, disruptions, Condensed Matter Physics, 01 natural sciences, 010305 fluids & plasmas, law.invention, Settore ING-INF/04 - Automatica, Nuclear Energy and Engineering, Runaway electrons, law, Compass, 0103 physical sciences, diagnostics, Fluid injection, tokamaks, MHD instabilities, 010306 general physics
Abstract

The role of the COMPASS tokamak in research of generation, confinement and losses of runaway electron (RE) population is presented. Recently, two major groups of experiments aimed at improved understanding and control of the REs have been pursued. First, the effects of the massive gas injection (~1021 Ar/Ne particles) and impurity seeding (~1018 particles) were studied systematically. The observed phenomena include generation of the post-disruption RE beam and current conversion from plasma to RE. Zero loop voltage control was implemented in order to study the decay in simplified conditions. A distinctive drop of background plasma temperature and electron density was observed following an additional deuterium injection into the RE beam. With the loop voltage control the parametric dependence of the current decay rate dI/dt can be studied systematically and possibly extrapolated to larger facilities. Second, recent results of experiments focused on the role of the magnetic field in physics of RE were analysed. In this contribution, special attention is given to the observed effects of the resonant magnetic perturbation on the RE population. The benefits of the RE experiments on COMPASS was reinforced by diagnostic enhancements (fast cameras, Cherenkov detector, vertical ECE etc) and modelling efforts (in particular, coupling of the METIS and LUKE codes).

Published
2019
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13. Overview of power exhaust experiments in the COMPASS divertor with liquid metals

Author

M. Iafrati, J. Adamek, Vladimir Weinzettl, S. Atikukke, David Tskhakaya, A. Prishvitcyn, J. Cecrdle, Miglena Dimitrova, J. Horacek, G. Van Oost, M. Jerab, Martin Hron, Petr Vondracek, G. Mazzitelli, M. Tomes, Pavel Veis, Martin Imrisek, Jordan Cavalier, D. Naydenkova, A.V. Vertkov, Jozef Varju, A. Marin Roldan, P. Barton, Estelle Gauthier, R. Dejarnac, Dejarnac, R., Horacek, J., Hron, M., Jerab, M., Adamek, J., Atikukke, S., Barton, P., Cavalier, J., Cecrdle, J., Dimitrova, M., Gauthier, E., Iafrati, M., Imrisek, M., Marin Roldan, A., Mazzitelli, G., Naydenkova, D., Prishvitcyn, A., Tomes, M., Tskhakaya, D., Van Oost, G., Varju, J., Veis, P., Vertkov, A., Vondracek, P., and Weinzettl, V.

Subjects
Nuclear and High Energy Physics, Liquid metal, Technology and Engineering, Tokamak, Materials science, Capillary action, Materials Science (miscellaneous), Nuclear engineering, Alloy, engineering.material, COMPASS, 01 natural sciences, 010305 fluids & plasmas, law.invention, Divertor, law, 0103 physical sciences, Perpendicular, 010302 applied physics, CAPILLARY-PORE SYSTEMS, Plasma, lcsh:TK9001-9401, TARGET, Nuclear Energy and Engineering, Heat flux, engineering, lcsh:Nuclear engineering. Atomic power, CPS, ELM
Abstract

Power handling experiments with a special liquid metal divertor module based on the capillary porous system technology were performed in the tokamak COMPASS. The performance of two metals (Li and LiSn alloy) were tested for the first time in a divertor under ELMy H-mode conditions. No damage of the capillary mesh and a good exhaust capability were observed for both metals in two separate experiments with up to 12 MW/m(2) of deposited perpendicular, inter-ELM steady-state heat flux and with ELMs of relative energy similar to 3% and a local peak energy fluence at the module similar to 15 kJ.m(-2). No droplets were directly ejected from the mesh top surface and for the LiSn experiment, no contamination of the core and SOL plasmas by Sn was observed. The elemental depth profile analysis of 14 stainless-steel samples located around the vacuum vessel for each experiment provides information about the migration of evaporated/redeposited liquid elements.

Published
2020

14. Overview of the COMPASS diagnostics

Author

Vladimir Weinzettl, Radek Melich, G. Anda, D. Sestak, M. Aftanas, J. Horacek, A. Szappanos, D. Jares, V. K. Kiselov, G. Veres, Joydeep Ghosh, M. Manso, F. Janky, I. Duran, M. Berta, H. W. Müller, Martin Hron, J. Brotankova, Radomir Panek, D.V. Sarychev, Petra Bilkova, Jan Mlynar, P. Bohm, R. Scannell, P. Hacek, Vladimir Shevchenko, S. Nanobashvili, Michael Walsh, V. Igochine, R. Dejarnac, J. Zajac, S. Zoletnik, F. Zacek, D. Naydenkova, Ana Elisa Bauer de Camargo Silva, Tsv K Popov, J. Stöckel, R.B. Gomes, J. Adamek, and Josef Havlicek

Subjects
Tokamak, COMPASS tokamak, business.industry, Mechanical Engineering, Divertor, Nanotechnology, Technical specifications, Diagnostic tools, law.invention, Nuclear Energy and Engineering, law, Compass, General Materials Science, Plasma diagnostics, Aerospace engineering, business, Civil and Structural Engineering
Abstract

The COMPASS tokamak, a divertor device with clear H-mode and ITER-relevant geometry, has been re-installed in IPP Prague after its transport from CCFE in UK. The first plasma was achieved in December 2008. Many new diagnostic tools with both high temporal and spatial resolutions have been developed to address the scientific programme of COMPASS focused on H-mode physics and pedestal investigations. In the paper, an overview of existing and in near future planned diagnostics (magnetic, spectroscopy, microwave, probe and beam/particle) on COMPASS is given including their basic technical specifications and achievements.

Published
2011

15. Design and engineering of optical diagnostics for COMPASS

Author

M.J. Walsh, Petra Bilkova, J. Stöckel, P. Bohm, Vladimir Weinzettl, I. Ďuran, D. Naydenkova, M. Aftanas, and D. Sestak

Subjects
Tokamak, Computer science, Thomson scattering, business.industry, Mechanical Engineering, Multispectral image, Fusion power, Laser, Signal, law.invention, Optics, Nuclear Energy and Engineering, law, Compass, General Materials Science, business, Image resolution, Civil and Structural Engineering
Abstract

The paper generally outlines a design of new multichannel optical diagnostics for the COMPASS (COMPact ASSembly) tokamak. The final design of a port plug for a multispectral diagnostic tool is introduced and its evolution taking into consideration spatial and other technical restrictions is reviewed. A similar solution of both focusing optics and optical signal diversion will be used for a new Thomson scattering (TS) system, which is specified in the second part of the article. Main parameters of the TS system, such as laser energy and regions of observation, were determined with respect to both electron temperature and density profiles and required ultrahigh spatial resolution at the plasma edge.

Published
2009

16. On the precision of absolute sensitivity calibration and specifics of spectroscopic quantities interpretation in tokamaks

Author

D. Naydenkova, J. Stöckel, Vladimir Weinzettl, and Jiří Matějíček

Subjects
Physics, Tokamak, Spectrometer, COMPASS tokamak, Thomson scattering, business.industry, Materials Science (miscellaneous), Industrial and Manufacturing Engineering, law.invention, Interpretation (model theory), Optics, law, Temporal resolution, Calibration, Sensitivity (control systems), Business and International Management, business
Abstract

Typical situations, which can be met during the process of absolute calibration, are shown in the case of a visible light observation system for the COMPASS tokamak. Technical issues and experimental limitations of absolute measurements connected with tokamak operation are discussed.

Published
2015

17. Divertor impurity seeding experiments at the COMPASS tokamak.

Author

M. Komm, I. Khodunov, J. Cavalier, P. Vondracek, S. Henderson, J. Seidl, J. Horacek, D. Naydenkova, J. Adamek, P. Bilkova, P. Bohm, A. Devitre, M. Dimitrova, S. Elmore, M. Faitsch, P. Hacek, J. Havlicek, A. Havranek, M. Imrisek, and J. Krbec

Subjects
HEAT flux, ENERGY dissipation, NUCLEAR fusion
Abstract

Partial detachment is the desired regime for the baseline burning plasma scenario in ITER and other next-step devices, as it allows for the dissipation of the majority of the energy carried by charged particles through the scrape-off-layer and thus avoids localised heat flux deposition in the divertor region. The COMPASS tokamak is equipped with an open divertor and has a relatively short connection length, both factors being unfavourable for access to detachment. As such, it only allows for the approach to naturally detached operation at very high line-averaged densities (>1020 m−3), which are incompatible with maintaining the ELMy H-mode regime. In order to achieve detachment at lower densities, impurities (such as nitrogen) must be injected into the plasma in the divertor region. A series of experiments with impurity injection in the range of 1–9 1020 molecules per second at different locations in the divertor were performed with the aim being to cool the plasma and influence particle and heat transport onto the divertor targets and provoke partial detachment. Previously reported results (Komm et al 2017 Proc. of the 44th EPS Conf. P1.118) were largely extended by injection of nitrogen at the outer divertor target. In order to analyze the divertor heat flux footprint in seeded plasmas, the buffered heat flux qB was introduced, with the radial profile being approximated by an exponential decay. A new set of generic parameters—the peak heat flux , the fraction of power reaching the target and divertor footprint spreading factor Sf — were proposed to characterise the divertor footprint under detached conditions. [ABSTRACT FROM AUTHOR]

Published
2019
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18. Runaway electron beam stability and decay in COMPASS.

Author

O. Ficker, E. Macusova, J. Mlynar, D. Bren, A. Casolari, J. Cerovsky, M. Farnik, O. Grover, J. Havlicek, A. Havranek, M. Hron, M. Imrisek, M. Jerab, J. Krbec, P. Kulhanek, V. Linhart, M. Marcisovsky, T. Markovic, D. Naydenkova, and R. Panek

Subjects
ELECTRON beams, NEUTRAL beams, DECAY rates (Radioactivity)
Abstract

This paper presents two scenarios used for generation of a runaway electron (RE) beam in the COMPASS tokamak with a focus on the decay phase and control of the beam. The first scenario consists of massive gas injection of argon into the current ramp-up phase, leading to a disruption accompanied by runaway plateau generation. In the second scenario, injection of a smaller amount of gas is used in order to isolate the RE beam from high-temperature plasma. The performances of current control and radial and vertical position feedback control in the second scenario were experimentally studied and analysed. The role of RE energy in the radial position stability of the RE beam seems to be crucial. A comparison of the decay phase of the RE beam in various amounts of Ar or Ne was studied using absolute extreme ultraviolet (AXUV) tomography and hard x-ray (HXR) intensity measurement. Argon clearly leads to higher HXR fluxes for the same current decay rate than neon, while radiated power based on AXUV measurements is larger for Ne in the same set of discharges. [ABSTRACT FROM AUTHOR]

Published
2019
Full Text
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19. Runaway electron experiments at COMPASS in support of the EUROfusion ITER physics research.

Author

E Macusova, D Naydenkova, J Urban, V Weinzettl, A Casolari, M Hron, J Havlicek, A Havranek, E Matveeva, R Panek, J Varju, P Kulhanek, J Mlynar, O Ficker, J Cerovsky, M Farnik, T Markovic, P Vondracek, M Imrisek, and O Bogar

Subjects
*ELECTRONS, *PLASMA physics, *ELECTRIC potential, *TEMPERATURE, *DEUTERIUM
Abstract

The role of the COMPASS tokamak in research of generation, confinement and losses of runaway electron (RE) population is presented. Recently, two major groups of experiments aimed at improved understanding and control of the REs have been pursued. First, the effects of the massive gas injection ( Ar/Ne particles) and impurity seeding ( particles) were studied systematically. The observed phenomena include generation of the post-disruption RE beam and current conversion from plasma to RE. Zero loop voltage control was implemented in order to study the decay in simplified conditions. A distinctive drop of background plasma temperature and electron density was observed following an additional deuterium injection into the RE beam. With the loop voltage control the parametric dependence of the current decay rate dI/dt can be studied systematically and possibly extrapolated to larger facilities. Second, recent results of experiments focused on the role of the magnetic field in physics of RE were analysed. In this contribution, special attention is given to the observed effects of the resonant magnetic perturbation on the RE population. The benefits of the RE experiments on COMPASS was reinforced by diagnostic enhancements (fast cameras, Cherenkov detector, vertical ECE etc) and modelling efforts (in particular, coupling of the METIS and LUKE codes). [ABSTRACT FROM AUTHOR]

Published
2019
Full Text
View/download PDF

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

Author

Joydeep Ghosh, Tiago M. D. Pereira, Vladimir Weinzettl, M. Tomes, Michael Pisarik, T. Odstrcil, Radek Melich, Martin Imrisek, R. B. Gomes, Rje Roger Jaspers, J. Varju, I. Abramovic, Gaurav Shukla, D. Naydenkova, G. Van Oost, Radomir Panek, Science and Technology of Nuclear Fusion, and Sensorics for fusion reactors

Subjects
Materials science, Tokamak, Ion temperature, Plasma spectroscopy, CXRS, law.invention, symbols.namesake, Optics, law, Physics::Plasma Physics, General Materials Science, Spectroscopy, Civil and Structural Engineering, Spectrometer, COMPASS tokamak, business.industry, Mechanical Engineering, Magnetic confinement fusion, Plasma, Nuclear Energy and Engineering, Plasma rotation, symbols, Atomic physics, business, Doppler effect, Doppler broadening
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.

21. Progress in diagnostics of the COMPASS tokamak

Author

J.P. Gunn, Daniel Dunai, T. Krizsanoczi, Petr Vondracek, Jordan Cavalier, G. Anda, M. Rabinski, E. Matveeva, M. Peterka, E. Gauthier, Tsv K Popov, J. Stöckel, Roberta Lima Gomes, S. Nanobashvili, D. I. Refy, Vladimir Weinzettl, D. Fridrich, Matthias Komm, Josef Havlicek, A. Havranek, Martin Imrisek, M. Varavin, Karol Malinowski, O. Grover, R. Paprok, M. Vlainic, J. Krbec, M. Berta, O. Bogar, Ondrej Ficker, D. Naydenkova, R. Dejarnac, J. Zajac, Martin Hron, J. Adamek, J. Zebrowski, M. Stano, Miglena Dimitrova, Petra Bilkova, S. Zoletnik, G. P. Ermak, M. Sos, P. Hacek, P. Bohm, Jakub Seidl, Radomir Panek, M. Tomes, Tomas Markovic, F. Zacek, A. Podolnik, K. Mitosinkova, Jozef Varju, D. Sarychev, N. Vianello, Jan Mlynar, K. Kovarik, M. Jakubowski, Monica Spolaore, Tiago M. D. Pereira, J. Horacek, A. Devitre, and António Rito Silva

Subjects
Nuclear instruments and methods for hot plasma diagnostics, Plasma confinement, 01 natural sciences, 010305 fluids & plasmas, Runaway electrons, Plasma instability, Physics::Plasma Physics, cameras, 0103 physical sciences, spectroscopy and imaging, Aerospace engineering, 010306 general physics, Instrumentation, tokamak, Mathematical Physics, Thomson scattering, Physics, neutral particle analyzer, COMPASS tokamak, business.industry, Iter tokamak, Magnetic confinement fusion, magnetic diagnostics, diagnostic beam, Plasma diagnostics - interferometry, Physics::Accelerator Physics, neutron detector, Plasma diagnostics - probes, Detector design and construction technologies and materials, business, probes, Cherenkov detector
Abstract

The COMPASS tokamak at IPP Prague is a small-size device with an ITER-relevant plasma geometry and operating in both the Ohmic as well as neutral beam assisted H-modes since 2012. A basic set of diagnostics installed at the beginning of the COMPASS operation has been gradually broadened in type of diagnostics, extended in number of detectors and collected channels and improved by an increased data acquisition speed. In recent years, a significant progress in diagnostic development has been motivated by the improved COMPASS plasma performance and broadening of its scientific programme (L-H transition and pedestal scaling studies, magnetic perturbations, runaway electron control and mitigation, plasma-surface interaction and corresponding heat fluxes, Alfvenic and edge localized mode observations, disruptions, etc.). In this contribution, we describe major upgrades of a broad spectrum of the COMPASS diagnostics and discuss their potential for physical studies. In particular, scrape-off layer plasma diagnostics will be represented by a new concept for microsecond electron temperature and heat flux measurements - we introduce a new set of divertor Langmuir and ball-pen probe arrays, newly constructed probe heads for reciprocating manipulators as well as several types of standalone probes. Among optical tools, an upgraded high-resolution edge Thomson scattering diagnostic for pedestal studies and a set of new visible light and infrared (plasma-surface interaction investigations) cameras will be described. Particle and beam diagnostics will be covered by a neutral particle analyzer, diagnostics on a lithium beam, Cherenkov detectors (for a direct detection of runaway electrons) and neutron detectors. We also present new modifications of the microwave reflectometer for fast edge density profile measurements.

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22. Divertor impurity seeding experiments at the COMPASS tokamak

Author

A. Havranek, Jakub Seidl, S. S. Henderson, M. Sos, A. Devitre, Miglena Dimitrova, J. Horacek, J. Adamek, Petr Vondracek, O. Samoylov, K. Tomova, Petra Bilkova, P. Bohm, Radomir Panek, M. Tomes, Matthias Komm, J. Krbec, Martin Imrisek, M. Faitsch, I. Khodunov, Jordan Cavalier, M. Peterka, Josef Havlicek, Vladimir Weinzettl, D. Naydenkova, P. Hacek, S. Elmore, and EUROfusion MST1 Team

Subjects
Nuclear and High Energy Physics, Materials science, Tokamak, COMPASS tokamak, Divertor, Nuclear engineering, Magnetic confinement fusion, Plasma, Condensed Matter Physics, 01 natural sciences, 010305 fluids & plasmas, law.invention, Impurity, law, 0103 physical sciences, Nuclear fusion, Seeding, 010306 general physics
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23. Contribution to the multi-machine pedestal scaling from the COMPASS tokamak

Author

J. Stöckel, O. Grover, Petr Vondracek, Martin Hron, Petra Bilkova, E. Stefanikova, P. Bohm, Vladimir Weinzettl, M. Sos, Martin Imrisek, M. Peterka, Jakub Urban, M. Berta, Matthias Komm, Josef Havlicek, J. Krbec, M. Aftanas, Lorenzo Frassinetti, P. B. Snyder, O. Bogar, Radomir Panek, P. Hacek, D. Naydenkova, K. Mitosinkova, and Jozef Varju

Subjects
Physics, Nuclear and High Energy Physics, COMPASS tokamak, business.industry, Plasma confinement, Magnetic confinement fusion, Condensed Matter Physics, 01 natural sciences, 010305 fluids & plasmas, Magnetic field, Multi machine, Pedestal, Plasma instability, 0103 physical sciences, Aerospace engineering, 010306 general physics, business, Scaling
Abstract

First systematic measurements of pedestal structure during Ohmic and NBI-assisted Type I ELMy H-modes were performed on the COMPASS tokamak in two dedicated experimental campaigns during 2015 and 2 ...

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24. Modeling of COMPASS tokamak divertor liquid metal experiments

Author

J. Cecrdle, P. Barton, M. Iafratti, S. Lukes, G. Mazzitelli, Slavomir Entler, Yu. M. Gasparyan, Estelle Gauthier, Jordan Cavalier, Vladimir Weinzettl, David Tskhakaya, M. Jerab, J. Hromadka, Martin Hron, Jozef Varju, Ya. A. Vasina, A.V. Vertkov, Radomir Panek, G. Van Oost, J. Adamek, A. Prishvitsin, Petr Vondracek, D. Naydenkova, Matthias Komm, Jakub Seidl, M. Tomes, J. Gerardin, R. Dejarnac, J. Horacek, D. Sestak, Horacek, J., Dejarnac, R., Cecrdle, J., Tskhakaya, D., Vertkov, A., Cavalier, J., Vondracek, P., Jerab, M., Barton, P., van Oost, G., Hron, M., Weinzettl, V., Sestak, D., Lukes, S., Adamek, J., Prishvitsin, A., Iafratti, M., Gasparyan, Y., Vasina, Y., Naydenkova, D., Seidl, J., Gauthier, E., Mazzitelli, G., Komm, M., Gerardin, J., Varju, J., Tomes, M., Entler, S., Hromadka, J., and Panek, R.

Subjects
THERMOGRAPHY, Nuclear and High Energy Physics, Liquid metal, Technology and Engineering, Materials science, Tokamak, Materials Science (miscellaneous), Evaporation, chemistry.chemical_element, HEAT, law.invention, Divertor, law, ITER, LITHIUM, Plasma facing components, COMPASS tokamak, Plasma, lcsh:TK9001-9401, Nuclear Energy and Engineering, Heat flux, chemistry, lcsh:Nuclear engineering. Atomic power, Lithium, THERMODYNAMIC PROPERTIES, Atomic physics, POINT, Liquid metals
Abstract

Two small liquid metal targets based on the capillary porous structure were exposed to the divertor plasma of the tokamak COMPASS. The first target was wetted by pure lithium and the second one by a lithium-tin alloy, both releasing mainly lithium atoms (sputtering and evaporation) when exposed to plasma. Due to poorly conductive target material and steep surface inclination (implying the surface-perpendicular plasma heat flux 12-17 MW/m(2)) for 0.1-0.2 s, the LiSn target has reached 900 degrees C under ELMy H-mode. A model of heat conduction is developed and serves to evaluate the lithium sputtering and evaporation and, thus, the surface cooling by the released lithium and consequent radiative shielding. In these conditions, cooling of the surface by the latent heat of vapor did not exceed 1 MW/m(2). About 10(19) lithium atoms were evaporated (comparable to the COMPASS 1 m(3) plasma deuterium content), local Li pressure exceeded the deuterium plasma pressure. Since the radiating Li vapor cloud spreads over a sphere much larger than the hot spot, its cooling effect is negligible (0.2 MW/m(2)). We also predict zero lithium prompt redeposition, consistent with our observation.Y

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25. Contribution to the multi-machine pedestal scaling from the COMPASS tokamak.

Author

M. Komm, P. Bílková, M. Aftanas, M. Berta, P. Böhm, O. Bogár, L. Frassinetti, O. Grover, P. Háček, J. Havlicek, M. Hron, M. Imríšek, J. Krbec, K. Mitošínková, D. Naydenkova, R. Pánek, M. Peterka, P.B. Snyder, E. Stefanikova, and J. Stöckel

Subjects
TOKAMAKS, TOROIDAL plasma, ELECTRON temperature, NUCLEAR physics, COLLISIONS (Nuclear physics)
Abstract

First systematic measurements of pedestal structure during Ohmic and NBI-assisted Type I ELMy H-modes were performed on the COMPASS tokamak in two dedicated experimental campaigns during 2015 and 2016. By adjusting the NBI heating and a toroidal magnetic field, the electron pedestal temperature was increased from 200 eV up to 300 eV, which allowed reaching pedestal collisionality   <  1 at q95 ~3. COMPASS has approached conditions for the Identity experiment done at JET & DIII-D, complementing the range of scanned . The pedestal pressure was successfully reproduced by the EPED model. The dependence of pedestal pressure width on and is discussed. [ABSTRACT FROM AUTHOR]

Published
2017
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