RMP optimization on KSTAR*

A new systematic RMP optimization represents a step toward safe ELM suppression by isolating the edge from core resonant fields. The optimization identifies the edge-optimized RMPs (ERMPs) in principle from the external fields without core-resonant response but keeps its efficiency in ELM suppression with the actual coils for experimental implementation. The ERMP is validated with accurate predictions, where it provides a 100% increase of ELM suppression window compared to the standard RMP in KSTAR. Furthermore, the new scheme allows the optimization across scenarios such that it would suppress ELMs in the H-mode phase but remain stable in the L-mode phase. This integrated optimization enabled the application of 3D fields before the L-H transition and showed the possibility to control the ELMs through the entire periods of discharge, including the first ELM crash which alone could lead to significant damage to the plasma-facing components. It turns out that the ERMP penetrated the edge resonant surface already before L-H transition with the zero perpendicular flow and delayed L-H transition timing with decreased non-linear interaction between zonal flow and turbulence. This result highlights the need to integrate different resonant field physics through the entire discharge.