Landau damping of the lower hybrid grill spectrum by tokamak edge electrons

0335852 - ÚFP 2010 RIV US eng C - Conference Paper (international conference)
Fuchs, Vladimír - Gunn, J. P. - Petržílka, Václav - Horáček, Jan - Seidl, Jakub - Ekedahl, A. - Goniche, M. - Hillairet, J.
Landau damping of the lower hybrid grill spectrum by tokamak edge electrons.
RADIO FREQUENCY POWER IN PLASMAS: Proceedings of the 18th Topical Conference. AIP Conference Proceedings. Vol. 1187. Melville: American Institute of Physics, 2009 - (Bobkov, V.; Noterdaeme, J.), s. 383-386. AIP Conference Proceedings, 1187. ISBN 978-0-7354-0753-4.
[Topical Conference on Radio Frequency Power in Plasmas/18th./. Ghent (BE), 24.06.2009-26.06.2009]
R&D Projects: GA ČR GA202/07/0044
Institutional research plan: CEZ:AV0Z20430508
Keywords : Lower hybrid wave * tokamak * plasma
Subject RIV: BL - Plasma and Gas Discharge Physics

According to theory and simulations Landau damping accelerates resonant electrons in front of a lower hybrid (LH) grill and generates substantial powerflows of order 1-10 MW/m2 along magnetic field lines. It is therefore of interest to understand the radial extent of this powerflow. Previous analyses predict interaction regions of order mm, whereas recent retarding field analyzer measurements detect energetic electron flows up to a few cm away from the grill mouth. It is shown here that the observed wide interaction region can be explained by electron Landau damping of the grill spectrum in the range 5<n//<200 by a mix of the thermal background with the generated fast electrons. Simulations show that in a typical Tore Supra tokamak plasma edge background with 25 MW/m2 of radiated antenna power density, the fast electrons exiting the grill region constitute about 7% of the electron population and are near-Maxwellian with a temperature of about 950 eV.
Permanent Link: http://hdl.handle.net/11104/0180208