Relative shift in position of temperature and density pedestals at the COMPASS tokamak.

0482690 - ÚFP 2018 RIV FR eng C - Conference Paper (international conference)
Bílková, Petra - Böhm, Petr - Komm, Michael - Frassinetti, L. - Štefániková, E. - Peterka, Matěj - Šos, Miroslav - Seidl, Jakub - Grover, Ondřej - Havlíček, Josef - Bogár, Klára - Varju, Jozef - Vondráček, Petr - Urban, Jakub - Imríšek, Martin - Markovič, Tomáš - Weinzettl, Vladimír - Hron, Martin - Pánek, Radomír
Relative shift in position of temperature and density pedestals at the COMPASS tokamak.
EPS 2017: 44th European Physical Society Conference on Plasma Physics. Vol. 41F. Mulhouse: European Physical Society, 2017 - (Fajardo, M.; Westerhof, E.; Riconda, C.; Melzer, A.; Bret, A.; Dromey, B.), č. článku P2.120. Europhysics Conference Abstracts (ECA). ISBN 979-10-96389-07.
[EPS 2017 Conference on Plasma Physics/44./. Belfast (IE), 26.06.2017-30.06.2017]
R&D Projects: GA ČR(CZ) GA14-35260S
EU Projects: European Commission(XE) 633053 - EUROfusion
Institutional support: RVO:61389021
Keywords : tokamak * COMPASS * plasma
OECD category: Fluids and plasma physics (including surface physics)

Recent analysis performed on ASDEX Upgrade, NSTX and DIII-D suggest that the density profile position plays an important role in pedestal stability [1,2,3]. On JET and ASDEX Upgrade, it has been observed that the electron temperature and electron density profiles can have different relative pedestal positions (so-called relative shift). As shown in [4,5], the increase of the relative shift is correlated with the reduction in the normalized pressure gradient, leading to a weakening of the pedestal stability. Therefore, in this work, analysis of the effect of the relative shift has been carried on the COMPASS tokamak discharges. The dataset used for analysis was obtained during two dedicated experimental campaigns in 2015 and 2016 [6]. Systematic measurements of pedestal structure were performed in Ohmic and NBIassisted Type I ELMy H-modes [7]. For PNBI exceeding 200 kW the electron pedestal temperature reached 300 eV, allowing to achieve pedestal collisionality Vped* < 1 at q95 ~3. Measurements during the last 30% of the ELM cycle were considered for analysis.
Permanent Link: http://hdl.handle.net/11104/0278323