JET scrape-off-layer ionization at lower hybrid wave launching

0377643 - ÚFP 2013 RIV GB eng J - Journal Article
Petržílka, Václav - Mailloux, J. - Ongena, J. - Corrigan, G. - Fuchs, Vladimír - Goniche, M. - Parail, V. - Belo, P. - Ekedahl, A. - Jacquet, P. - Mayoral, M.-L. - Silva, C. - Stamp, M.
JET scrape-off-layer ionization at lower hybrid wave launching.
Plasma Physics and Controlled Fusion. Roč. 54, č. 7 (2012), 074005-074005. ISSN 0741-3335. E-ISSN 1361-6587.
[IAEA Fusion Energy Conference /23rd./. Daejon, 11.10.2010-16.10.2010]
R&D Projects: GA ČR GA202/07/0044; GA ČR GAP205/10/2055; GA MŠMT(CZ) LG11018
Keywords : LH wave * plasma * LH grill * electrons * SOL * JET * ELMs
Subject RIV: BL - Plasma and Gas Discharge Physics
Impact factor: 2.369, year: 2012
http://iopscience.iop.org/0741-3335/54/7/074005/pdf/0741-3335_54_7_074005.pdf

We present in this paper modelling of the JET scrape-off layer (SOL) including direct SOL ionization by launched lower hybrid (LH) waves. For that purpose, the two-dimensional fluid code EDGE2D-NIMBUS was modified in order to account for possible enhanced ionization in the SOL, due to the LH power absorbed by the electrons in a layer extending in the radial direction from the launcher. By taking the direct LH SOL ionization into account, the observed modification of the density in front of the LH antenna during a LH power and gas injection, can be explained. The JET grill private SOL limiters, acting as sinks for the particles, are also included in the model. We compare the efficiency of gas puffing from the top and the outer mid-plane for SOL density enhancement and improvement in LH coupling. The observed reduction of the temporal variation of the LH wave reflection coefficient and of measured saturated currents in the SOL during ELMs, is explained. The density depletion
Permanent Link: http://hdl.handle.net/11104/0209746