3D divertor plasma modeling for stellarators and tokamaks with non-axisymmetric magnetic fields: an overview of contributions to KSTAR, ITER and W7-X

The suppression of edge-localized modes (ELMs) in tokamaks by application of resonant magnetic perturbations (RMPs) implies non-axisymmetric alterations of particle and heat fluxes to divertor targets.

For ITER, it is crucial to maintain a partial detachment and ELM suppression at the same time.

3D simulations with EMC3-EIRENE have shown that the heat flux remains attached in the outer part of the striations, and extrapolations to burning plasmas show that this remains at an acceptable level when neon seeding is applied.

However, a strong sensitivity on plasma response modeling has been identified.

The FLARE code for field line analysis and mesh construction can interface plasma response data from GPEC, MARS-F, M3D-C1, JOREK, HINT or VMEC/BMW.

For KSTAR, good agreement between GPEC and MARS-F is found for magnetic footprints, but both models overestimate the size of striations observed by infra-red measurements.

Better agreement is found for plasma response input from JOREK.

Supporting the design of divertor targets and baffles in stellarators, a new field line reconstruction module is implemented in FLARE based on unstructured quadrilateral flux tubes with local refinement.