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Plasma Sci. Technol. ›› 2018, Vol. 20 ›› Issue (7): 075101.doi: 10.1088/2058-6272/aab48f

• Magnetically Confined Plasma • Previous Articles     Next Articles

Magnetic-island-induced ion temperature gradient mode: Landau damping, equilibrium magnetic shear and pressure flattening effects

Wei WANG (王玮)1, Zhengxiong WANG (王正汹)1, Jiquan LI (李继全)3, Yasuaki KISHIMOTO2, Jiaqi DONG (董家齐)3,4 and Shu ZHENG (郑殊)1   

  1. 1 Key Laboratory of Materials Modification by Beams of the Ministry of Education, School of Physics, Dalian University of Technology, Dalian 116024, People’s Republic of China
    2 Graduate School of Energy Science, Kyoto University, Gokasyo, Uji, Kyoto 611-0011, Japan
    3 Southwestern Institute of Physics, Chengdu 610041, People’s Republic of China
    4 Institute for Fusion Theory and Simulation, Zhejiang University, Hangzhou 310027, People’s Republic of China  
  • Received:2017-12-06 Published:2018-03-05
  • Supported by:

    This work is supported by National Natural Science Foundation of China with Nos. 11305027, 11322549 and 11675038, National Magnetic Confinement Fusion Science Program of China with No. 2014GB124000 and partly supported by the Fundamental Research Funds for the Central Universities with Grant No. DUT15YQ103.

Abstract:

Characteristics of the magnetic-island-induced ion temperature gradient (MITG) mode are studied through gyrofluid simulations in the slab geometry, focusing on the effects of Landau damping, equilibrium magnetic shear (EMS), and pressure flattening. It is shown that the magnetic island may enhance the Landau damping of the system by inducing the radial magnetic field. Moreover, the radial eigenmode numbers of most MITG poloidal harmonics are increased by the magnetic island so that the MITG mode is destabilized in the low EMS regime. In addition, the pressure profile flattening effect inside a magnetic island hardly affects the growth of the whole MITG mode, while it has different local effects near the O-point and the X-point regions. In comparison with the non-zero-order perturbations, only the quasi-linear flattening effect due to the zonal pressure is the effective component to impact the growth rate of the mode.

Key words: magnetic island, magnetic shear, Landau damping, MITG