Direct plasma potential measurements by ball-pen probe and self-emitting langmuir probe on COMPASS and ASDEX upgrade

0435707 - ÚFP 2015 RIV DE eng J - Journal Article
Adámek, Jiří - Horáček, Jan - Seidl, Jakub - Müller, H.W. - Schrittwieser, R. - Mehlmann, F. - Vondráček, Petr - Pták, Svatopluk … Total 10 authors
Direct plasma potential measurements by ball-pen probe and self-emitting langmuir probe on COMPASS and ASDEX upgrade.
Contributions to Plasma Physics. Roč. 54, č. 3 (2014), s. 279-284. ISSN 0863-1042. E-ISSN 1521-3986
R&D Projects: GA ČR(CZ) GAP205/12/2327
Institutional support: RVO:61389021 ; RVO:61388998
Keywords : Tokamak * ball-pen probe * emissive probe * L-mode * plasma potential
Subject RIV: BL - Plasma and Gas Discharge Physics; BL - Plasma and Gas Discharge Physics (UT-L)
Impact factor: 0.838, year: 2014

Experimental investigations of the plasma potential by means of a ball-pen probe and self-emitting Langmuir probe technique were performed on the tokamaks COMPASS and ASDEX Upgrade. A spontaneous transition between the cold and self-emitting Langmuir probe has been observed during the deep reciprocation in the vicinity or even inside the last closed flux surface (LCFS) of both tokamaks. These measurements of the plasma potential allow us to compare two independent probe techniques based on heating and non-heating processes. The observed different conditions of the spontaneous transition can be ascribed to different physical mechanisms. Nevertheless, the comparison of the power spectra of ball-pen probe and self-emitting Langmuir probe indicates very good agreement in all measurements and therefore these two probe techniques are interchangeable.
Permanent Link: http://hdl.handle.net/11104/0239529