EAST上RMP驱动等离子体自发旋转物理机制的实验研究  

Experimental investigations on physical mechanisms of RMP-induced intrinsic rotations at EAST

作　　者：金仡飞 张洪明 尹相辉 吕波 Cheonho Bae 叶凯萱 盛回 王士凡 赵海林 顾帅 袁泓 林子超 傅盛宇 卢迪安 符佳 王福地 Jin Yi-Fei;Zhang Hong-Ming;Yin Xiang-Hui;LüBo;Cheonho Bae;Ye Kai-Xuan;Sheng Hui;Wang Shi-Fan;Zhao Hai-Lin;Gu Shuai;Yuan Hong;Lin Zi-Chao;Fu Sheng-Yu;Lu Di-An;Fu Jia;Wang Fu-Di(Institute of Plasma Physics,Hefei Institutes of Physical Science,Chinese Academy of Sciences,Hefei 230031,China;Science Island Branch,Graduate School of University of Science and Technology of China,Hefei 230026,China;School of Electrical Engineering,University of South China,Hengyang 421001,China;Enn Science and Technology Development Co.,Ltd.,Langfang 065001,China;School of Nuclear Science and Technology,University of Science and Technology of China,Hefei 230026,China;School of Nuclear Science and Technology,University of South China,Hengyang 421001,China)

机构地区：[1]中国科学院合肥物质科学研究院等离子体物理研究所,合肥230031 [2]中国科学技术大学研究生院科学岛分院,合肥230026 [3]南华大学电气工程学院,衡阳421001 [4]新奥科技发展有限公司,廊坊065001 [5]中国科学技术大学核科学技术学院,合肥230026 [6]南华大学核科学技术学院,衡阳421001

出　　处：《物理学报》2024年第24期187-197,共11页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:12175278,U23A2077);湖南省教育厅重点项目和青年项目(批准号:21B0439);中国科学院国际人才计划(批准号:2022VMB0007)资助的课题.

摘　　要：等离子体自发旋转对托卡马克装置的约束性能和稳定性十分重要.能否有效地诱导等离子体自发旋转来致稳电阻壁模对国际热核聚变实验堆(International Thermonuclear Experimental Reactor,ITER)的稳定运行尤为关键.在韩国先进超导托卡马克(Korea Superconducting Tokamak Advanced Research,KSTAR)装置上首次实验证明了在特定参数下,共振磁扰动(resonant magnetic perturbation,RMP)产生的新经典环向黏滞(neoclassical torodial viscosity,NTV)力矩能够驱动等离子体旋转.先前在东方超环托卡马克(Experimental Advanced Superconducting Tokamak,EAST)的RMP实验中同样也观测到了RMP加入后等离子体旋转在同电流方向增加的实验现象,然而与KSTAR不同,EAST上模拟计算的NTV力矩比中性束力矩小两个量级,无法解释环向旋转速度的增加.本文开展了进一步的研究,首先通过实验方法测得了RMP产生的力矩分布,与之前模拟得到的NTV力矩相比要大两个量级,说明存在NTV以外的机制驱动等离子体旋转.其次,在实验中观察到旋转速度增大的同时也伴随有E×B速度的明显变化,并且,与实验测量得到的RMP产生的力矩分布一致,表明E×B剪切的变化产生的残余应力可能是导致RMP加入后旋转速度增大的原因.为了解释RMP加入后环向旋转速度的增大,本文分析了RMP加入后随机磁场对大尺度湍流的影响,发现各尺度湍流在随机磁场的背景下,为了维持准中性条件,小尺度湍流的增长可能会导致雷诺应力的增大.在RMP加入期间,雷诺应力驱动E×B剪切的增大会破坏湍流对称性,产生残余应力驱动环向旋转.最后,实验的统计结果也表明,RMP对环向旋转的驱动效果与湍流强度有关,进一步验证了RMP加入E×B剪切产生的残余应力是驱动环向旋转变化的主要机制.Plasma spontaneous rotation significantly affects confinement performance and stability in tokamaks.Effectively inducing this rotation is essential for stabilizing resistive wall modes(RWMs)and ensuring the stable operation of the International Thermonuclear Experimental Reactor(ITER).Recent experiments conducted on the Korea Superconducting Tokamak Advanced Research(KSTAR)device demonstrated that resonant magnetic perturbations(RMPs)can induce neoclassical toroidal viscosity(NTV)torque under certain conditions,successfully driving plasma rotation.Similarly,on the Experimental Advanced Superconducting Tokamak(EAST),an increase in plasma rotation in the direction of the plasma current has been observed following RMP application.However,unlike the KSTAR findings,the NTV torque simulations for EAST are two orders of magnitude lower than experimental measurements,indicating additional mechanisms beyond NTV may drive the observed plasma rotations.In this paper,to investigate these mechanisms,momentum balance,causality,and statistical analyses are performed at EAST.An increase in rotation velocity is found to correlate with significant changes in the E×Bflow, matching the RMP-induced torque distribution. This alignment suggests that residual stress, arising from variations in E×Bshear, may cause the observed rotation to increase. The effects of stochastic fields on multi-scale turbulence are considered as a possible explanation for correlations between E×Bvelocity and toroidal rotation. Stochastic fields appear to enhance the inertia of large-scale turbulence while driving small-scale turbulence to maintain quasi-neutrality. The resulting turbulent Reynolds stress, generated by small-scale turbulence, may account for the increases of the observed E×Bvelocity during RMP application. Statistical analysis further highlights the importance of island width in understanding the threshold RMP current in ramping-up RMP experiments, supporting the conclusion that turbulence-driven E×Bshear-related residual stress is the ke

关 键 词：托卡马克 动量输运 自发旋转 共振磁扰动 

分 类 号：O53[理学—等离子体物理]