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Post-disruptive runaway electron beams in the COMPASS tokamak

Part of: Focus on Fusion Energetic Electrons

Published online by Cambridge University Press:  11 August 2015

Milos Vlainic ,
J. Mlynar ,
J. Cavalier ,
V. Weinzettl ,
R. Paprok ,
M. Imrisek ,
O. Ficker ,
M. Varavin ,
P. Vondracek  and
J.-M. Noterdaeme
...Show all authors
Milos Vlainic*
Affiliation:
Department of Applied Physics, Ghent University, Ghent 9000, Belgium Institute of Plasma Physics AS CR, Prague 18200, Czech Republic
J. Mlynar
Affiliation:
Institute of Plasma Physics AS CR, Prague 18200, Czech Republic
J. Cavalier
Affiliation:
Institute of Plasma Physics AS CR, Prague 18200, Czech Republic
V. Weinzettl
Affiliation:
Institute of Plasma Physics AS CR, Prague 18200, Czech Republic
R. Paprok
Affiliation:
Institute of Plasma Physics AS CR, Prague 18200, Czech Republic Faculty of Mathematics and Physics, Charles University, Prague 12116, Czech Republic
M. Imrisek
Affiliation:
Institute of Plasma Physics AS CR, Prague 18200, Czech Republic Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University, Prague 11519, Czech Republic
O. Ficker
Affiliation:
Institute of Plasma Physics AS CR, Prague 18200, Czech Republic Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University, Prague 11519, Czech Republic
M. Varavin
Affiliation:
Institute of Plasma Physics AS CR, Prague 18200, Czech Republic
P. Vondracek
Affiliation:
Institute of Plasma Physics AS CR, Prague 18200, Czech Republic
J.-M. Noterdaeme
Affiliation:
Department of Applied Physics, Ghent University, Ghent 9000, Belgium Max Planck Institute for Plasma Physics, Garching 85748, Germany
*
†Email address for correspondence: milos.vlainic@ugent.be
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Abstract

For ITER-relevant runaway electron studies, such as suppression, mitigation, termination and/or control of a runaway beam, it is important to obtain the runaway electrons after the disruption. In this paper we report on the first discharges achieved with a post-disruptive runaway electron beam, termed a ‘runaway plateau’, in the COMPASS tokamak. The runaway plateau is produced by a massive gas injection of argon. Almost all of the disruptions with runaway electron plateaus occurred during the plasma current ramp-up phase. The Ar injection discharges with and without a runaway plateau were compared for various parameters. Parametrisation of the discharges shows that the COMPASS disruptions fulfil the range of parameters important for runaway plateau occurrence. These parameters include electron density, electric field, disruption speed, effective safety factor, and the maximum current quench electric field. In addition to these typical parameters, the plasma current value just before the massive gas injection proved to be surprisingly important.

Type
Research Article
Information
Journal of Plasma Physics , Volume 81 , Issue 5 , October 2015 , 475810506
Copyright
© The Author(s) 2015 

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