Speaker
Jiaqi Dong
Description
See the full Abstract at http://ocs.ciemat.es/EPS2018ABS/pdf/P2.1095.pdf
Impurity induced kinetic micro-electromagnetic instabilities in toroidal
plasmas
J. Q. Dong1,2, Yong Shen1, W. L. Zhong 1, A. P. Sun1, M. K. Han3,1, Z. X. Wang3, H. D.
He1, X. L. Zou4
1 Southwestern Institute of Physics, Chengdu, 610041, China
2 Institute of Fusion Theory and Simulation, Zhejiang University, Hangzhou, 310027,
China
3 Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Ministry of
Education), School of Physics, Dalian University of Technology, Dalian, 116024, China
4 CEA, IRFM, F-13108 Saint-Paul-lez-Durance, France
Abstract
New kinetic micro-electromagnetic instabilities are found in magnetically confined
toroidal plasmas in the presence impurity ions with gyrokinetic simulations [1]. The
instabilities are induced by impurity ion density gradient, which is parallel (negative) or
opposite (positive) to the gradient of electrons, and finite (plasma pressure/magnetic
pressure) effect even in the absence of ion temperature gradient and trapped electrons.
The requirements of dual critical impurity density gradients (one positive and one
negative), finite impurity charge concentration and plasma are identified for the
instabilities to be exited. The instabilities are identified as kinetic shear Alfvén and
kinetic ballooning types, respectively, and are unstable in the first and second stable
regimes of the ideal MHD ballooning modes and may have significant influence on
plasma confinement. Possible relevance with the recent experimental observation in the
pedestal of H-mode plasmas on HL-2A tokamak and further experimental investigations
[2-4] are discussed.
References
[1] Yong Shen, J. Q. Dong, A. P. Sun et al., Plasma Phys. Control. Fusion 58, 045028 (2016).
[2] Z.Y. Cui, S. Morita, H.Y. Zhou et al., Nucl. Fusion 53, 093001(2013).
[3] Yong Shen, J.Q. Dong, A.P. Sun, M.K. Han et al., Nucl. Fusion 58, 014004 (2018).
[4] W. L. Zhong, Y. Shen, X. L. Zou et al., Phys. Rev. Lett. 117, 045001 (2016).
