ADVANCES IN THE PROBE TECHNIQUE DIAGNOSTICS OF FUSION PLASMA (VEIT2017)

0479844 - ÚFP 2018 RIV BG eng O - Others
Hasan, E. - Dimitrova, Miglena - Popov, Tsv.K. - Ivanova, P. - Dejarnac, Renaud - Stöckel, Jan
ADVANCES IN THE PROBE TECHNIQUE DIAGNOSTICS OF FUSION PLASMA (VEIT2017).
2017
R&D Projects: GA MŠMT(CZ) LM2015045; GA ČR(CZ) GA16-24724S
Institutional support: RVO:61389021
Keywords : Electron energy distribution function * electron temperatura and density * first-derivative probe technique * four-parameter fit * sheath expansion
OECD category: Fluids and plasma physics (including surface physics)

Předneseno na: 20th International Summer School Vacuum, Electron and Ion Technologies (VEIT2017), Sozopol, 25-29.09.2017.
The Langmuir probe is among the most frequently used tools in evaluating the plasma potential, electron temperature and density in the vicinity of the last closed flux surface (LCFS) and in the scrape-off layer (SOL) of tokamaks.
However, in some cases in tokamak SOL plasmas, the EEDF can deviate from Maxwellian. To correctly obtain the EEDF, for more than ten years now the first-derivative probe technique (FDPT) has been applied to determine the plasma potential and the real electron energy distribution function in fusion plasmas. In this work, a comparison between recent results obtained by the FDPT and the conventional probe technique is performed in the case of sheath expansion of the ion part of the IV probe characteristics. It is demonstrated how this technique should be applied in the case of an unsaturated ion part. Possible difficulties in recognizing the sheath expansion are also discussed. A good agreement between the four-parameter fit and the first-derivative probe technique is demonstrated.

Permanent Link: http://hdl.handle.net/11104/0275770