The narrow feature in power flux deposition profiles in COMPASS limiter plasmas

0433986 - ÚFP 2015 BG eng C - Conference Paper (international conference)
Dejarnac, Renaud - Stangeby, P.C. - Goldston, R.J. - Horáček, Jan - Hron, Martin - Komm, Michael - Pánek, Radomír - Vondráček, Petr - Gauthier, E. - Kocan, M. - Pitts, R.A. … Total 12 authors
The narrow feature in power flux deposition profiles in COMPASS limiter plasmas.
International Workshop & Summer School on Plasma Physics. Sofia: University of Sofia, 2014.
[International Workshop & Summer School on Plasma Physics/6./. Kiten (BG), 30.06.2014-06.07.2014]
Institutional support: RVO:61389021
Keywords : Power flux * narrow channel * limiter * plasma * tokamak
Subject RIV: BL - Plasma and Gas Discharge Physics

The current ramp-up phase of ITER discharges will be in limiter configuration, with the high field side (HFS) wall as the favored start-up surface. Recent experimental observations on JET using IR thermography show a clear narrow feature in the parallel heat flux density q// near the Last Closed Flux Surface of inner wall limiter (ILW) plasmas. A significant effort has subsequently been made on the COMPASS tokamak to investigate this effect using a specially diagnosed (IR thermography + Langmuir probes), roof-shaped IWL. Using detailed analysis of the probe data, in combination with power fluxes derived from IR measurements, this paper discusses the possible physics mechanisms that could give rise to the narrow heat flux channel. Evidence of a narrow heat flux feature with a power decay length of λq,omp ~5 mm is obtained with the probes, consistent with the findings from IR thermography viewing the same limiter. One possible contribution to this narrow feature might be a
Permanent Link: http://hdl.handle.net/11104/0238125