Runaway electron beam stability and decay in COMPASS

0509572 - ÚFP 2020 RIV AT eng J - Journal Article
Ficker, Ondřej - Tomešová, Eva - Mlynář, Jan - Břeň, D. - Casolari, Andrea - Čeřovský, Jaroslav - Farník, Michal - Grover, Ondřej - Havlíček, Josef - Havránek, Aleš - Hron, Martin - Imríšek, Martin - Jeřáb, Martin - Krbec, Jaroslav - Kulhánek, Petr - Linhart, V. - Marcisovský, M. - Markovič, Tomáš - Naydenkova, Diana - Pánek, Radomír - Šos, Miroslav - Svihra, P. - Svoboda, Vojtěch - Tomeš, Matěj - Urban, Jakub - Varju, Jozef - Vlainic, Milos - Vondráček, Petr - Vrba, V. - Weinzettl, Vladimír - Carnevale, D. - Decker, J. - Gobbin, M. - Gospodarczyk, M. - Papp, G. - Peysson, Y. - Plyusnin, V.V. - Rabinski, M. - Reux, C.
Runaway electron beam stability and decay in COMPASS.
Nuclear Fusion. Roč. 59, č. 9 (2019), č. článku 096036. ISSN 0029-5515. E-ISSN 1741-4326
R&D Projects: GA ČR(CZ) GA18-02482S; GA MŠMT(CZ) LM2015045; GA MŠMT(CZ) 8D15001
EU Projects: European Commission(XE) 633053 - EUROfusion
Institutional support: RVO:61389021
Keywords : disruptions * runaway electrons * Tokamaks * tomography
OECD category: Fluids and plasma physics (including surface physics)
Impact factor: 3.706, year: 2019
Method of publishing: Limited access
https://iopscience.iop.org/article/10.1088/1741-4326/ab210f

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 erature 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.
Permanent Link: http://hdl.handle.net/11104/0300282