Study of Secondary Instability of 2/1 Magnetic Island in COMPASS High Density Limit Plasmas.

0482424 - ÚFP 2018 RIV FR eng C - Conference Paper (international conference)
Salzedas, F. - Shah, S.I.W. - Havlíček, Josef - Stöckel, Jan - Háček, Pavel - Varju, Jozef - Havránek, Aleš - Pánek, Radomír - Silva, C.
Study of Secondary Instability of 2/1 Magnetic Island in COMPASS High Density Limit Plasmas.
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 P4.129. 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 MŠMT(CZ) LM2015045
Institutional support: RVO:61389021
Keywords : tokamaks * COMPASS
OECD category: Fluids and plasma physics (including surface physics)

For generating fusion power, high plasma density is indispensable for reactor tokamaks but it may lead to the density limit disruption (DLD). The physical mechanisms behind the underlying processes of DLD are only partially understood. The growing MHD instabilities are often regarded as precursors to DLD. A secondary instability to the rotating (2,1) magnetic island was observed prior to the thermal quench, when the amplitude of the magnetic island is large and its rotation frequency is low, first in JET and then in COMPASS tokamaks.
The secondary instability is characterized by small amplitude perturbations, with no m or n mode numbers, superimposed on the perturbations of the precursor magnetic island. The frequency of the SI is higher than the rotating frequency of the island itself.
The presented work focuses on the study of the SI behaviour in the period preceding the thermal quench.

Permanent Link: http://hdl.handle.net/11104/0277834