Plasma potential and electron temperature evaluated by ball-pen and Langmuir probes in the COMPASS tokamak.

0480361 - ÚFP 2018 RIV GB eng J - Journal Article
Dimitrova, Miglena - Popov, Tsv.K. - Adámek, Jiří - Kovačič, J. - Ivanova, P. - Hasan, E. - López-Bruna, D. - Seidl, Jakub - Vondráček, Petr - Dejarnac, Renaud - Stöckel, Jan - Imríšek, Martin - Pánek, Radomír
Plasma potential and electron temperature evaluated by ball-pen and Langmuir probes in the COMPASS tokamak.
Plasma Physics and Controlled Fusion. Roč. 59, č. 12 (2017), č. článku 125001. ISSN 0741-3335. E-ISSN 1361-6587
R&D Projects: GA ČR(CZ) GA15-10723S; GA MŠMT(CZ) LM2015045
Institutional support: RVO:61389021
Keywords : Plasma potential * electron temperature * bi-Maxwellian EEDF * ball-pen probe * Langmuir probe * COMPASS tokamak * last closed flux surface
OECD category: Fluids and plasma physics (including surface physics)
Impact factor: 3.032, year: 2017

The radial distributions of the main plasma parameters in the scrape-off-layer of the COMPASS tokamak are measured during L-mode and H-mode regimes by using both Langmuir and ball-pen probes mounted on a horizontal reciprocating manipulator. The radial profile of the plasma potential derived previously from Langmuir probes data by using the first derivative probe technique is compared with data derived using ball-pen probes. A good agreement can be seen between the data acquired by the two techniques during the L-mode discharge and during the H-mode regime within the inter-ELM periods. In the vicinity of the last closed flux surface, where the electron energy distribution function is bi-Maxwellian, the ball-pen probe technique results are in agreement with the high-temperature components of the electron distribution only. We also discuss the application of relatively large Langmuir probes placed in parallel and perpendicularly to the magnetic field lines to studying the main plasma parameters.
Permanent Link: http://hdl.handle.net/11104/0277626