径向电场对离子温度梯度模稳定性的影响  

Effect of radial electric field on ion-temperature gradient driven mode stability

作　　者：陈凝飞 魏广宇 仇志勇 Chen Ning-Fei;Wei Guang-Yu;Qiu Zhi-Yong(Institute for Fusion Theory and Simulation,School of Physics,Zhejiang University,Hangzhou 310027,China;Center for Nonlinear Plasma Science and ENEA C.R.Frascati,Frascati,Italy)

机构地区：[1]浙江大学物理学院,聚变理论与模拟中心,杭州310027 [2]Center for Nonlinear Plasma Science and ENEA C.R.Frascati,Frascati,Italy

出　　处：《物理学报》2023年第21期167-176,共10页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:12275236,12261131622)资助的课题.

摘　　要：为了理解托卡马克装置中给定径向电场对离子温度梯度模(ITG)稳定性的影响,基于非线性回旋动理学理论和气球模表象推导了环位形下包含径向电场引起的极向流和密度扰动影响的ITG的本征模方程,并分别在长/短波长极限下研究了高能量粒子诱发测地声模(EGAM)所伴随的径向电场对ITG的本征频率、增长率和平行模结构的影响.不仅对该本征模方程进行了理论研究,还使用本征矩阵法对其进行数值求解,以便对理论结果进行验证.研究发现EGAM伴随的电场引起的极向转动会大幅降低ITG的增长率,而极向模数m=1的密度扰动对ITG的线性稳定性影响很小.这一结果与一般认为的带状流通过极向流剪切抑制湍流的结果是一致的.除此之外,使用本文发展的一般性方法也可以研究高能量粒子激发的阿尔芬不稳定性与漂移波湍流通过阿尔芬不稳定性激发带状结构发生的间接非线性相互作用,即带状结构所伴随的径向电场通过极向转动和密度扰动影响ITG的稳定性.该间接非线性通道可以作为对主导背景等离子体输运的微观湍流和主导高能量粒子输运的阿尔芬不稳定性之间的直接相互作用通道的补充.To understand the effect of given radial electric field on ion-temperature gradient driven mode(ITG)stability in tokamak plasmas,we derive the eigenmode equation for ITG including the poloidal rotation and density modulation associated with radial electric field by using nonlinear gyrokinetic theory.The equation is solved for the eigenfrequency,growth rate and parallel mode structure of ITG both in short-and longwavelength limit with energetic-particle-induced geodesic acoustic mode(EGAM)as a specific form.The eigenmode equation is not only solved analytically,but also solved numerically to validate the analytic solutions.It is found that,the radial electric field induced poloidal rotation can significantly stabilize ITG,while the density perturbation of the radial electric field may slightly distort the ITG parallel mode structure,but has little effect on ITG stability.The result is consistent with the common picture of turbulence suppression by poloidal shear flow.The general model is also applicable to the investigation of the indirect interaction of ITG and energetic particle driven Alfvén instabilities via zonal structures generation,by introducing poloidal rotation and density modulation associated with zonal structures spontaneously excited by Alfvén instabilities.The indirect channel is supplement to the direct interaction of microturbulences and energetic particle driven Alfvén instabilities.

关 键 词：离子温度梯度模 径向电场 高能量粒子诱发测地声模 非线性回旋动理学理论 

分 类 号：TL631.24[核科学技术—核技术及应用]