Nonlinear Modeling of the Effect of n=2 Resonant Magnetic Field Perturbation on Peeling-Ballooning Mode in KSTAR

The impact of n=2 resonant magnetic perturbation (RMP) on the pedestal and peeling-ballooning mode (PBM) is investigated using the nonlinear 3D MHD code JOREK. It is based on the reduced MHD equations (viscos-resistive MHD), and the experimental parameters from the RMP-driven Edge localized mode (ELM) suppression discharge in KSTAR. In this study, n=2 kink-peeling mode was triggered through nonlinear coupling with RMP, and the pedestal is degraded by increased radial transport due to both tearing and kink-peeling response. The ELM mitigation and suppression are observed when RMP of sufficient amplitude is applied. ELM suppression was characterized by spatial locking of mode structure. In the simulation, the ELM suppression is not only due to the degraded pedestal but is also related to the mode coupling between the PBMs and the RMP-induced mode at the plasma edge. The role of PBM locking in mode suppression is suggested in terms of mode coupling.