Observation and Simulation of n=1 Reversed Shear Alfvén Eigenmode on the HL-2A Tokamak  

作　　者：P.W.Shi Y.R.Yang W.Chen Z.B.Shi Z.C.Yang L.M.Yu T.B.Wang X.X.He X.Q.Ji W.L.Zhong M.Xu X.R.Duan 

机构地区：[1]Southwestern Institute of Physics,Chengdu 610041,China [2]State Key Laboratory of Intense Pulsed Radiation Simulation and Effect,Northwest Institute of Nuclear Technology,Xi’an 710024,China

出　　处：《Chinese Physics Letters》2022年第10期26-33,共8页中国物理快报（英文版）

基　　金：supported by the National Key R&D Program of China(Grant No.2019YFE03020000);the National Natu ral Science Foundation of China(Grant No.12125502);the Sichuan Science and Technology Program(Grants No.2020JDJQ0070);the Natural Science Foundation of Sichuan(Grant No.2022NSFSC1823).

摘　　要：A branch of high-frequency Alfvenic modes is observed on the HL-2A tokamak.The electromagnetic mode can be driven unstably in the plasma with an off-axis neutral beam heating.Its mode frequency keeps almost unchanged or presents a slow-sweeping behavior,depending on the detail current evolution.The poloidal and toroidal mode numbers are𝑚m/n=1/1.The mode has a quite short duration(≤20 ms)and usually appears 5-10 ms after the neutral beam being injected into the plasma.Hybrid simulations based on M3D-K have also been carried out.The result suggests that co-passing energetic particles are responsible for the mode excitation.The simulated mode structures are localized nearby location of minimum safety factor(q_(min))and agree with the structures obtained through tomography of soft x-ray arrays.Further,the modes are localized in the continuum gap and their frequencies increase with variation of𝑞min in a wide range.Last but not least,the characteristic of unchanged frequency on experiment is also reproduced by the nonlinear simulation with a fixed safety factor.All those evidences indicate that the𝑛n=1 high-frequency mode may belong to a reversed shear Alfven eigenmode.

关 键 词：Alfven MODE unchanged 

分 类 号：TL631.24[核科学技术—核技术及应用]