Impact of Resonant Magnetic Perturbations Scenarios on Detachment for ITER

A scan of gas injection into the scrape-off layer (SOL) conducted with EMC3-EIRENE for different resonant magnetic perturbation (RMP) scenarios shows how differences in the edge plasma magnetic geometry impacts detachment in ITER’s pre-fusion power operation (PFPO) configuration. ITER will suppress edge localized modes (ELM) by applying RMPs to provoke a response in the plasma edge. The distorted edge alters the flux to the divertor surface, raising concerns that the non-axisymmetric plasma surface interaction may inhibit detachment or induce intolerable localized heat flux. A previous study of how RMPs impact detachment for ITER PFPO showed that the region near the main strike point detaches more promptly in the density scan, but that the far SOL region remains attached [H. Frerichs et al., Nuclear Fusion (2021)]. This study compares n3, n4, and hybrid toroidal mode RMPs with phasing for optimized X-point displacement, as an ELM suppression metric. Detachment at the main strike point occurs most promptly for the largest magnetic footprint scenario but sustains high heat flux in the far SOL. These trends between the magnetic footprint and heat flux facilitate the selection of RMP configurations in an ELM suppressing subspace to optimize heat and particle loads on the divertor.