Nonlinear simulation of ELM dynamics in the presence of resonant magnetic perturbations

Abstract

We report on nonlinear simulation studies on the dynamical behaviour of ELMs under the influence of resonant magnetic perturbations (RMPs) using a two-fluid initial value electromagnetic nonlinear global code (CUTIE). To simulate ELMs we introduce a particle source in the confinement region and a particle sink in the edge region. To study ELM control using RMPs we have applied an n = 2 static external magnetic perturbation at the edge and made detailed parametric studies under varying conditions for the machine and plasma parameters typical of COMPASS-D. Our results show that ELM mitigation is possible for RMP powers beyond a specific threshold. The results also provide valuable insights into the RMP induced modifications of the complex nonlinear dynamics of the ELMs, in particular on the redistribution of mode energy and the cascading of energy to shorter scale lengths. We also observe a hysteresis in states as we increase the amplitude of RMPs and then decrease it to the same value.