Open AccessHeat pulse propagation across the rational surface in a large helical device plasma with counter-neutral beam injection
Author(s) -
M. A. Yakovlev,
S. Inagaki,
Τ. Shimozuma,
S. Kubo,
T. Morisaki,
Y. Nagayama,
K. Kawahata,
A. Komori
Publication year - 2005
Publication title -
physics of plasmas
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.75
H-Index - 160
eISSN - 1089-7674
pISSN - 1070-664X
DOI - 10.1063/1.2044447
Subject(s) - physics , rational surface , toroid , plasma , neutral beam injection , atomic physics , magnetic field , large helical device , flattening , beam (structure) , electron temperature , heat flux , electron , cyclotron , optics , heat transfer , tokamak , mechanics , nuclear physics , quantum mechanics , astronomy
Core electron temperature profile flattening is observed in a large helical device [A. Iiyoshi et al. Nucl. Fusion 39, 1245 (1999)] inward shifted plasma with counter-neutral beam injection. To study this phenomenon, heat pulse experiments are performed by on-axis electron cyclotron heating power modulation. A unique feature of heat pulse propagation is observed near the m∕n=2∕1 rational surface (m, n are the poloidal and toroidal mode numbers, respectively). A simultaneous response of the temperature perturbation on radially separated flux surfaces is shown. The change in the magnetic field topology due to the presence of a magnetic island structure can explain this nonmonotonic heat pulse propagation. The estimated O-point position of the island is located near the m∕n=2∕1 rational surface.
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