Resonant magnetic perturbation-mediated nonlinear interaction and its impact on magnetic field stochastization in pedestal collapse simulations

Abstract

We investigate the effect of externally applied resonant magnetic perturbations (RMPs) on the pedestal collapse, using resistive reduced magnetohydrodynamic simulations. The RMP-mediated nonlinear interaction is shown to enhance the fluctuation level, leading to an increase of convective transport. Further, it also induces a broad coherence and strong energy transfer among poloidal and toroidal harmonics. The enhanced fluctuations, especially at lower (than the most unstable mode) toroidal mode number n, eventually increase the tearing-parity fluctuation distinctively at lower n through a series of tearing-parity generation mechanism. Consequently, RMPs are shown to expedite the magnetic field line stochastization process via the nonlinear energy transfer process.