Studies of runaway electrons via Cherenkov effect in tokamaks

0508698 - ÚFP 2020 RIV GB eng C - Conference Paper (international conference)
Zebrowski, J. - Jakubowski, L. - Rabinski, M. - Sadowski, M. J. - Jakubowski, M.J. - Kwiatkowski, R. - Malinowski, K. - Mirowski, R. - Mlynář, Jan - Ficker, Ondřej - Weinzettl, Vladimír - Causa, F.
Studies of runaway electrons via Cherenkov effect in tokamaks.
Journal of Physics: Conference Series. Vol. 1046. Bristol: IOP Publishing Ltd., 2018, Roč. 959, č. 1 (2018), č. článku 012002. ISSN 1742-6588.
[International Conferences on Research and Applications of Plasmas (PLASMA). Varšava (PL), 17.09.2017-22.09.2017]
R&D Projects: GA MŠMT(CZ) LM2015045
EU Projects: European Commission(XE) 633053 - EUROfusion
Institutional support: RVO:61389021
Keywords : runaway electrons * tokamak
OECD category: Atomic, molecular and chemical physics (physics of atoms and molecules including collision, interaction with radiation, magnetic resonances, Mössbauer effect)
https://iopscience.iop.org/article/10.1088/1742-6596/959/1/012002/pdf

The paper concerns measurements of runaway electrons (REs) which are generated during discharges in tokamaks. The control of REs is an important task in experimental studies within the ITER-physics program. The NCBJ team proposed to study REs by means of Cherenkov-type detectors several years ago. The Cherenkov radiation, induced by REs in appropriate radiators, makes it possible to identify fast electron beams and to determine their spatial- and temporal-characteristics. The results of recent experimental studies of REs, performed in two tokamaks COMPASS in Prague and FTU in Frascati, are summarized and discussed in this paper. Examples of the electron-induced signals, as recorded at different experimental conditions and scenarios, are presented. Measurements performed with a three-channel Cherenkov-probe in COMPASS showed that the first fast electron peaks can be observed already during the current ramp-up phase. A strong dependence of RE-signals on the radial position of the Cherenkov probe was observed. The most distinct electron peaks were recorded during the plasma disruption. The Cherenkov signals confirmed the appearance of post-disruptive RE beams in circular-plasma discharges with massive Ar-puffing. During experiments at FTU a clear correlation between the Cherenkov detector signals and the rotation of magnetic islands was identified.
Permanent Link: http://hdl.handle.net/11104/0299533