Effect of edge plasma density on hot spot in LHCD plasma in EAST

B.J. Ding; C.B. Wu; Y.C. Li; M.H. Li; Y.F. Wang; B. Zhang; G.H. Yan; H.Q. Liu; L. Wang; M. Wang; R. Ding; H.C. Hu; H. Lian; R. Cesario; A.A. Tuccillo; S.G. Baek; P Bonoli; A. Ekedahl; J.F. Shan; F.K. Liu; J.P. Qian; X.Z. Gong; B.N. Wan

Nuclear Materials and Energy (Jun 2021)

Effect of edge plasma density on hot spot in LHCD plasma in EAST

B.J. Ding,
C.B. Wu,
Y.C. Li,
M.H. Li,
Y.F. Wang,
B. Zhang,
G.H. Yan,
H.Q. Liu,
L. Wang,
M. Wang,
R. Ding,
H.C. Hu,
H. Lian,
R. Cesario,
A.A. Tuccillo,
S.G. Baek,
P Bonoli,
A. Ekedahl,
J.F. Shan,
F.K. Liu,
J.P. Qian,
X.Z. Gong,
B.N. Wan

Affiliations

B.J. Ding: Institute of Plasma Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China; Corresponding authors.
C.B. Wu: Institute of Plasma Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China; University of Science and Technology of China, Hefei 230026, China
Y.C. Li: College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China; Corresponding authors.
M.H. Li: Institute of Plasma Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China
Y.F. Wang: Institute of Plasma Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China; University of Science and Technology of China, Hefei 230026, China
B. Zhang: Institute of Plasma Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China
G.H. Yan: Institute of Plasma Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China; University of Science and Technology of China, Hefei 230026, China
H.Q. Liu: Institute of Plasma Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China
L. Wang: Institute of Plasma Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China
M. Wang: Institute of Plasma Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China
R. Ding: Institute of Plasma Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China
H.C. Hu: Institute of Plasma Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China
H. Lian: Institute of Plasma Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China
R. Cesario: ENEA, Fusion and Nuclear Safety Department, C. R. Frascati, Via E. Fermi 45, 00044 Frascati (Roma), Italy
A.A. Tuccillo: ENEA, Fusion and Nuclear Safety Department, C. R. Frascati, Via E. Fermi 45, 00044 Frascati (Roma), Italy
S.G. Baek: MIT Plasma Science and Fusion Center, Cambridge, MA 02139, USA
P Bonoli: MIT Plasma Science and Fusion Center, Cambridge, MA 02139, USA
A. Ekedahl: CEA, IRFM, F-13108 Saint-Paul-lez-Durance, France
J.F. Shan: Institute of Plasma Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China
F.K. Liu: Institute of Plasma Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China
J.P. Qian: Institute of Plasma Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China
X.Z. Gong: Institute of Plasma Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China
B.N. Wan: Institute of Plasma Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China

Journal volume & issue: Vol. 27
p. 100992

Abstract

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Hot spot is a serious challenge limiting long pulse operation with LHCD (lower hybrid current drive) in tokamak. In order to mitigate the hot spot in guard limiter and improve LHCD capability, effect of edge plasma density on inducing hot spot and current drive has been studied in EAST. The temperature in the guard limiter of the LH antenna, inducing hot spot directly, increases with edge density and LH power. Studies show that the hot spot is mainly ascribed to the heat flux in front of LH antenna. Further simulation indicates that such spot corresponds to the peak position of edge density due to local LH electric field. In addition, due to the stronger parametric instability (PI) behavior in the case of higher edge density, the current drive capability decreases with edge density. Strike-point splitting behaviors appear with density increase, in agreement with current profiles in the edge region and the reduction of total driven current, suggesting that more power is deposited in edge region, which does more contribution to hot spot. Above studies offer one possible idea to optimize the edge density so as to satisfy the coupling, mitigate the heat flux in the guard limiter, and improve current drive capability for fusion device.

Published in Nuclear Materials and Energy

ISSN: 2352-1791 (Online)
Publisher: Elsevier
Country of publisher: United Kingdom
LCC subjects: Technology: Electrical engineering. Electronics. Nuclear engineering: Nuclear engineering. Atomic power
Website: http://www.journals.elsevier.com/nuclear-materials-and-energy/

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