Simulations of the SOL plasma for FAST, a proposed ITER satellite tokamak

The first simulations with EDGE2D/EIRENE code of the SOL plasma in the FAST tokamak have been run for the basic H-mode scenario. Its similarity to ITER and relevance for DEMO bring interest to the study. Five different preliminary divertor designs have been examined by varying density at separatrix over the plausible range ns,out = 0.7–1.0 × 1020 m−3. Margins exist for optimizing the design and minimizing the impurity injection rate even at the lowest density, with load below the safe limit of 18 MW/m2 on the monoblock W targets, and to achieve a good degree of detachment at higher density. Both the plate tilting angle and the neutral dynamics are crucial factors. The detachment level can be significantly increased for the higher density scenario, while for the full non-inductive operation the injection of impurities will probably be necessary to reduce the heat load.