Observation of electron-scale turbulence suppression under weak magnetic shear with neon seeding in EAST plasma

Nuclear Fushion

article

Y.Q. Chu¹  B.S. Zhang²  P. Li²  X.D. Yang²  H.Q. Liu²  Y.X. Jie²  C.B. Wu²  W.M. Zhang²  K.D. Li²  T.F. Zhou²  L. He²  Q. Zang²  H. Lian²  F.B. Zhong¹  R.J. Zhu²  L. F. Zhang³  K. Hanada⁴ 

[1] College of Physics and Optoelectronic Engineering, Shenzhen University;Institute of Plasma Physics, Chinese Academy of Sciences;University of Science and Technology of China;Research Institute for Applied Mechanics, Kyushu University

关键词: PIC-MCC model;    plasma-wall interaction;    divertor monoblocks;    SEE;    thermionic emission;   

DOI  :  10.1088/1741-4326/acdd83

来源: Institute of Physics Publishing Ltd.

【 摘 要 】

Improved confinement caused by Ne injection is investigated in EAST. The safety factorqprofile and electron-scale turbulence are studied with a polarimeter-interferometer system and CO₂ laser collective scattering system in a series of Ne injection experiments in EAST. Ne with a suitable injection rate can lead to negative magnetic shear in the plasma core, which promotes electron-scale turbulence suppression. The continuous injection of Ne under the reversed shear condition further reduces the electron-scale turbulence intensity. Core electron temperature increase and confinement improvement are observed. QuaLiKiz is applied to model the influence of an impurity and reversedqon turbulence. The combination of stabilization effects of negative magnetic shear and Ne on turbulence is much stronger than the impurity's own effect, which could explain the experimentally observed electron temperature ( T _e) increase and turbulence suppression. Besides, the relationship between pedestal structure induced by Ne injection and lower hybrid wave (LHW)-driven current deposition is discussed. These results provide a new perspective to improve the confinement in the case of Ne injection, i.e. to adjust the Ne injection to modify the ideal plasma equilibrium.

【 授权许可】

Unknown