Global total-f gyrokinetic study of turbulence before and during RMP ELM-suppression in DIII-D

We apply the global total-f gyrokinetic code XGC to study pedestal turbulence shortly before and during RMP-ELM suppression in DIII-D. Turbulence was found to increase with the strength of the external RMP field in KSTAR experiments. While earlier electrostatic XGC simulations with fixed RMP fields confirmed that RMPs can increase turbulent transport, the role of turbulent transport in the transition to the ELM suppressed state is not fully understood. We investigate this question with gyrokinetic simulations of the edge and scrape-off layer plasma for two plasma equilibria from a DIII-D H-mode, taken before and during ELM suppression, respectively. The simulations self-consistently include neoclassical and turbulent transport as well as a neutral recycling source. Electrostatic and electromagnetic turbulent modes, from low to high toroidal mode numbers are included. The results are compared with the RMP fields from the MHD code M3D-C1, which are used to initialize the simulations, and linear MHD stability calculations.