Progress of theoretical and simulation studies on resistive wall mode stabilization by plasma rotation

With a focus on instability called resistive wall mode (RWM), this paper introduced the progress of theoretical research aimed at elucidating the stabilization mechanism based on plasma rotation. The initial theory was the theory that was described with 'ideal' magnetohydrodynamics (MHD) and, in addition, when there was no rotation. Subsequently, a paper followed, where tokamak coordination was numerically solved by incorporating the effect of equilibrium plasma rotation onto the linearized resistive MHD equation. Experimental results could be well explained with this paper. Next, a kinetic MHD theory corresponding to the RWM stabilization experiment result based on low plasma rotation appeared. In addition, a kinetic MHD theory including the effect of rotation was expanded. A model focusing on the effect of rotation shear and the effect of high-energy particles was proposed and the experiments are proceeding. This paper has mentioned linear theory, but nonlinear MHD simulation and the elucidation of RWM saturation level are separate important research subjects. As an important research theme in future high-performance tokamak research, the construction of a simplified model from a detailed formulation and its use for disruption prediction can be pointed out. (A.O.)