文献类型：期刊文献

英文题名：Theory of gyrokinetic velocity moment and its application for zonal flows in a tokamak plasma

作者：Zhang, Debing[1];Xu, Yingfeng[2];Dai, Zongliang[3];Wang, Shaojie[3]

机构：[1]East China Univ Sci & Technol, Dept Phys, Shanghai 200237, Peoples R China;[2]Chinese Acad Sci, Inst Plasma Phys, Hefei 230031, Peoples R China;[3]Univ Sci & Technol China, Dept Engn & Appl Phys, Hefei 230026, Peoples R China

年份：2020

卷号：60

期号：4

外文期刊名：NUCLEAR FUSION

收录：;EI(收录号：20201308355738);WOS:【SCI-EXPANDED(收录号:WOS:000519028200001)】；

基金：One of the authors, Debing Zhang, thanks Prof Lu Wang for her helpful discussion. This work was supported by the National Natural Science Foundation of China under Grant Nos. 11875254, 11775265 and 11675176, and by the Users with Excellence Project of Hefei Science Center CAS under Grant No. 2018HSC-UE009.

语种：英文

外文关键词：gyrokinetic theory; scalar invariance; velocity moment; turbulent poloidal Reynolds stress; zonal radial electric field

摘要：The calculation of the velocity moment in the gyrokinetic theory and its application in the study of zonal flows in a tokamak plasma are investigated. Based on the scalar invariance property, the expression for the particle velocity in the gyrocenter coordinates is obtained, and a method to systematically calculate the velocity moment in the gyrokinetic theory is proposed, especially for the calculation of the first-order perpendicular velocity moment. The kinetic equation which describes the evolution of the perturbed distribution on the meso-scale of the zonal flow is derived. The effects of the turbulent particle flux, the turbulent energy flux, the turbulent toroidal Reynolds stress and the turbulent poloidal Reynolds stress (PRS) are explicitly included in the phase-space particle flux. In the cylindrical geometry, the zonal radial electric field is driven by the turbulent PRS and the turbulent energy flux, and the result agrees with the radial force balance equation. In the toroidal geometry, the zonal radial electric field is driven by the turbulent PRS, the turbulent energy flux and the turbulent toroidal Reynolds stress; in contrast to the case in the cylindrical geometry, the effect of the turbulent PRS is shielded by the toroidal effect. By combining the radial force balance equation, the poloidal momentum equation in the toroidal geometry is obtained.