Plasma interaction with tungsten samples in the COMPASS tokamak in ohmic ELMy H-modes

0460257 - ÚFP 2017 RIV GB eng C - Conference Paper (international conference)
Dimitrova, Miglena - Weinzettl, Vladimír - Matějíček, Jiří - Popov, T. - Marinov, S. - Costea, S. - Dejarnac, Renaud - Stöckel, Jan - Havlíček, Josef - Pánek, Radomír
Plasma interaction with tungsten samples in the COMPASS tokamak in ohmic ELMy H-modes.
Journal of Physics Conference Series. Vol. 700. Bristol: IOP Publishing, Ltd., 2016, s. 012008. IOPscience. ISSN 1742-6588. E-ISSN 1742-6596.
[International Summer School on Vacuum, Electron and Ion Technologies/19./. Sozopol (BG), 21.09.2015-25.09.2015]
R&D Projects: GA ČR(CZ) GA14-12837S; GA MŠMT(CZ) LM2011021
Institutional support: RVO:61389021
Keywords : Divertor probes * H-mode * tungsten samples * electron energy distribution function * parallel power flux density
OECD category: Fluids and plasma physics (including surface physics)
http://iopscience.iop.org/article/10.1088/1742-6596/700/1/012008

This paper reports experimental results on plasma interaction with tungsten samples with or without pre-grown He fuzz. Under the experimental conditions, arcing was observed on the fuzzy tungsten samples, resulting in localized melting of the fuzz structure that did not extend into the bulk. The Langmuir probes embedded in the divertor tiles on the COMPASS tokamak were used to measure a current-voltage probe characteristics, during ohmic ELMy H-modes reached in deuterium plasmas at a toroidal magnetic field 1.15 T, plasma current 300 kA and line-averaged electron density 5×1019 m−3. The data obtained between the ELMs were processed by the recently published first-derivative probe technique for precise determination of the plasma potential and the electron energy distribution function (EEDF).
The spatial profile of the EEDF shows that at the high-field side it is Maxwellian with a temperature of 5 – 10 eV. The electron temperatures and the ion-saturation current density obtained were used to evaluate the radial distribution of the parallel power flux density as being in the order of 0.05 – 7 MW/m2.

Permanent Link: http://hdl.handle.net/11104/0260379