Numerical study of runaway current impact on sawtooth oscillations in tokamaks  

作　　者：Ruirui MA Chen ZHAO Yao ZHOU Chang LIU 马瑞瑞;赵忱;周尧;刘畅(Southwestern Institute of Physics,Chengdu 610041,People’s Republic of China;Center for Nonlinear Plasma Science,ENEA C.R.Frascati,Frascati 00044,Italy;General Atomics,San Diego,California 92186-5608,United States of America;School of Physics and Astronomy,Institute of Natural Sciences,and MOE-LSC,Shanghai Jiao Tong University,Shanghai 200240,People’s Republic of China;Princeton Plasma Physics Laboratory,New Jersey 08540,United States of America)

机构地区：[1]Southwestern Institute of Physics,Chengdu 610041,People’s Republic of China [2]Center for Nonlinear Plasma Science,ENEA C.R.Frascati,Frascati 00044,Italy [3]General Atomics,San Diego,California 92186-5608,United States of America [4]School of Physics and Astronomy,Institute of Natural Sciences,and MOE-LSC,Shanghai Jiao Tong University,Shanghai 200240,People’s Republic of China [5]Princeton Plasma Physics Laboratory,New Jersey 08540,United States of America

出　　处：《Plasma Science and Technology》2025年第3期10-21,共12页等离子体科学和技术(英文版)

基　　金：supported in part by the National Key R&D Program of China (No.2022YFE03040002);the Natural Science Foundation of Sichuan (No.2022NSFSC1814);National Natural Science Foundation of China (Nos.12305246,12175053 and 12261131622);the Italian Ministry of Foreign Affairs (No.CN23GR02);the Fundamental Research Funds for the Central Universities;supported by US Department of Energy (No.DE-AC0209CH11466)。

摘　　要：This study investigates the influence of runaway current in runaway plasmas on the dynamics of sawtooth oscillations and resultant loss of runaway electrons(RE)using the 3D magnetohydrodynamic(MHD)code M3D-C^(1)(Jardin et al 2012 J.Comput.Sci.Discovery 6014002).Using an HL-2A-like equilibrium,we confirm that in the linear phase,the impact of REs on resistive internal kink instabilities is consistent with previous research.In the nonlinear phase,as the runaway current fully replaces the plasmas current,we observe a significant suppression of sawtooth oscillations,with the first sawtooth cycle occurring earlier compared to the case without runaway current.Following the first sawtooth collapse,plasma current density,runaway current density,and safety factor(q)flatten within the q=1 surface,albeit displaying fine structures.Subsequently,the growing high torodial(n)and poloidal(m)mode number modes disrupt the magnetic surfaces,leading to the loss of REs outside the q=1 surface,while minimally affecting the majority of REs well-confined within it.Thus,in the current model,the physical processes associated with the presence of sawtooth oscillations do not effectively dissipate runaway current,as REs are assumed to be collisionless.In addition,the final profile of runaway current density exhibits increased steepening near the q=1 surface in contrast to the initial profile,displaying a distinctive corrugated inhomogeneity influenced by the growing fluctuation of the n=0 component.Finally,detailed convergence tests are conducted to validate the numerical simulations.

关 键 词：DISRUPTION runaway current sawtooth oscillations RE loss 

分 类 号：TL6[核科学技术—核技术及应用]