A drift-kinetic perturbed Lagrangian for low-frequency nonideal MHD applications  

作　　者：徐国盛 伍兴权 胡友俊 Guosheng XU;Xingquan WU;Youjun HU(Institute of Plasma Physics,Hefei Institutes of Physical Science,Chinese Academy of Sciences,Hefei 230031,People’s Republic of China)

机构地区：[1]Institute of Plasma Physics,Hefei Institutes of Physical Science,Chinese Academy of Sciences,Hefei 230031,People’s Republic of China

出　　处：《Plasma Science and Technology》2023年第7期35-41,共7页等离子体科学和技术（英文版）

基　　金：supported by the National Magnetic Confinement Fusion Energy Program of China(No.2019YFE03030000);National Natural Science Foundation of China(Nos.11905253 and U19A20113)。

摘　　要：We find that the perturbed Lagrangian derived from the drift-kinetic equation in[Porcelli F et al 1994 Phys.Plasmas 1470]is inconsistent with the ordering for the low-frequency large-scale magnetohydrodynamic(MHD).Here,we rederive the expression for the perturbed Lagrangian within the framework of nonideal MHD using the ordering system for the low-frequency largescale MHD in a low-beta plasma.The obtained perturbed Lagrangian is consistent with Chen's gyrokinetic theory[Chen L and Zonca F 2016 Rev.Mod.Phys.88015008],where the terms related to the field curvature and gradient are small quantities of higher order and thus negligible.As the perturbed Lagrangian has been widely used in the literature to calculate the plasma nonadiabatic response in low-frequency MHD applications,this finding may have a significant impact on the understanding of the kinetic driving and dissipative mechanisms of MHD instabilities and the plasma response to electromagnetic perturbations in fusion plasmas.

关 键 词：perturbed Lagrangian drift kinetic low-frequency nonideal MHD fusion plasma 

分 类 号：O53[理学—等离子体物理]