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Time‐dependent plasma transport simulation for the study of edge impurity radiation dynamics with magnetic island in large helical device
Author(s) -
Kobayashi Masahiro,
Tokar Mikhail Z.
Publication year - 2020
Publication title -
contributions to plasma physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.531
H-Index - 47
eISSN - 1521-3986
pISSN - 0863-1042
DOI - 10.1002/ctpp.201900138
Subject(s) - plasma , resonant magnetic perturbations , impurity , large helical device , physics , instability , magnetic field , radiation , materials science , atomic physics , condensed matter physics , mechanics , optics , toroid , quantum mechanics
The dynamics of impurity radiation distribution during detachment transition with edge magnetic island induced by the application of resonant magnetic perturbation (RMP) is studied numerically by solving time‐dependent plasma fluid equations together with impurity and neutral transports in a 2D grid system. Computations provide the appearance of a macroscopic structure in the heat transfer along the island separatrix and outside the island. The resultant parallel temperature gradient generates the plasma flow and the density gradient according to the parallel momentum balance. The resulting plasma flow effectively transports impurity towards the X‐point region. As a result, the impurity radiation is more intense near the X‐point than in the vicinity of the O‐point. This leads to the predominant cooling of the region around the X‐point. These results are in agreement with experimental observation with RMP application in the large helical device (LHD). The time scale of the thermal condensation instability is found to be of the order of 10 ms.