Sawtooth-like oscillations and steady states caused by the m/n=2/1 double tearing mode  

作　　者：Wei ZHANG Zhiwei MA Haowei ZHANG Xin WANG 张威;马志为;张豪伟;王鑫(Institute for Fusion Theory and Simulation,Department of Physics,Zhejiang University,Hangzhou 310027,People's Republic of China)

机构地区：[1]Institute for Fusion Theory and Simulation,Department of Physics,Zhejiang University,Hangzhou 310027,People's Republic of China

出　　处：《Plasma Science and Technology》2022年第3期89-97,共9页等离子体科学和技术（英文版）

基　　金：supported by National MCF Energy R&D Program of China(Nos.2019YFE03090500 and 2019YFE03030004);National Natural Science Foundation of China(Nos.12005185,11775188 and 11835010);Fundamental Research Fund for Chinese Central Universities(No.2021FZZX003-03-02)。

摘　　要：The sawtooth-like oscillations resulting from the m/n=2/1 double tearing mode(DTM)are numerically investigated through the three-dimensional,toroidal,nonlinear resistive-MHD code(CLT).We find that the nonlinear evolution of the m/n=2/1 DTM can lead to sawtooth-like oscillations,which are similar to those driven by the kink mode.The perpendicular thermal conductivity and the external heating rate can significantly alter the behaviors of the DTM driven sawtooth-like oscillations.With a high perpendicular thermal conductivity,the system quickly evolves into a steady state with m/n=2/1 magnetic islands and helical flow.However,with a low perpendicular thermal conductivity,the system tends to exhibit sawtooth-like oscillations.With a sufficiently high or low heating rate,the system exhibits sawtooth-like oscillations,while with an intermediate heating rate,the system quickly evolves into a steady state.At the steady state,there exist the non-axisymmetric magnetic field and strong radial flow,and both are with helicity of m/n=2/1.Like the steady state with m/n=1/1 radial flow,which is beneficial for preventing the helium ash accumulation in the core,the steady state with m/n=2/1 radial flow might also be a good candidate for the advanced steady state operations in future fusion reactors.We also find that the behaviors of the sawtooth-like oscillations are almost independent of tokamak geometry,which implies that the steady state with saturated m/n=2/1 islands might exist in different tokamaks.

关 键 词：DTM reversed magnetic shear pressure crash sawteeth SAWTOOTH double tearing mode steady state advanced scenario 

分 类 号：TL631.24[核科学技术—核技术及应用]