Understanding narrow SOL power flux component in COMPASS limiter plasmas by use of Langmuir probes

0444974 - ÚFP 2016 RIV NL eng J - Journal Article
Dejarnac, Renaud - Stangeby, P.C. - Goldston, R.J. - Gauthier, E. - Horáček, Jan - Hron, Martin - Kocan, M. - Komm, Michael - Pánek, Radomír - Pitts, R.A. - Vondráček, Petr
Understanding narrow SOL power flux component in COMPASS limiter plasmas by use of Langmuir probes.
Journal of Nuclear Materials. Roč. 463, August (2015), s. 381-384. ISSN 0022-3115. E-ISSN 1873-4820.
[PLASMA-SURFACE INTERACTIONS 21: International Conference on Plasma-Surface Interactions in Controlled Fusion Devices. Kanazawa, 26.05.2014-30.05.2014]
R&D Projects: GA ČR GAP205/11/2341; GA ČR(CZ) GAP205/12/2327; GA MŠMT(CZ) LM2011021
Institutional support: RVO:61389021
Keywords : COMPASS * tokamak * Heat loads * limiter * narrow channel * probes
OECD category: Nuclear related engineering
Impact factor: 2.199, year: 2015
http://www.sciencedirect.com/science/article/pii/S0022311514010538#

The narrow scrape-off layer power component observed in COMPASS inner wall limiter circular discharges by means of IR thermography is investigated by Langmuir probes embedded in the limiter. The power flux profiles are in good agreement with IR observations and can be described by a double-exponential decay with a short decay length (<5 mm) just outside the separatrix and a longer one (~50 mm) for the rest of the profile in the main scrape-off layer. Non-ambipolar currents measured at the limiter apex play a relatively modest role in the formation of the narrow component. The fraction of the deposited power due to non-ambipolarity varies between 2% and 45%. On the other hand, narrow power widths are roughly consistent with ones indicated by neo-classical considerations which suggests that the latter effects may be dominant
Permanent Link: http://hdl.handle.net/11104/0247401