Kinetic-magnetohydrodynamic hybrid simulation of infernal modes in circular tokamak plasmas with effects of kinetic thermal ions

Abstract

Abstract Effects of the kinetic thermal ions on ideal infernal modes and resistive infernal modes have been investigated by using magnetohydrodynamic (MHD) simulation without kinetic thermal ions and kinetic-MHD hybrid simulation with kinetic thermal ions. For the ideal infernal modes, the pressure profile is significantly flattened at the saturated state for both the models with and without the kinetic thermal ions. As the beta value decreases, the ideal infernal modes are stabilized while the resistive infernal modes are still unstable. For the resistive infernal modes, while the saturated pressure profile is significantly flattened in the MHD simulation without kinetic thermal ions, the pressure profile is not flattened at the saturated state in the kinetic-MHD hybrid simulation with kinetic thermal ions. The suppression of the saturation level by the effects of the kinetic thermal ions results from the phase mismatch between the radial velocity and perturbed pressure mode structures. This indicates that kinetic thermal ions play an essential role for the suppression of pressure profile flattening due to slowly growing resistive MHD instabilities.