Authors

Abstract

We modeled plasma edge localized mode (ELM) sputter erosion for a Small Angle Slot divertorwith a tungsten coated region (SAS-VW), designed for experiments in the DIII-D tokamak, andproposed for use in future advanced tokamaks. The simulations use a free-streaming, 1000 eV,C+6and D+1 ELM impingement model, with SOLPS-ITER, ITMC-DYN, and REDEP/WBCcode packages for background plasma, material response, and erosion/redeposition respectively.The results show ELMing plasma gross and net tungsten erosion fluxes of the mixed-materialC/W surface peaking at the slot entrance region, and an order of magnitude higher than fornon-ELMs. The per-pulse erosion, however, remains low, of order 0.5 nm, due to expectedmoderate ELM frequencies and duration in DIII-D. The ELMs result in a 25x higher peaksputtered W current leaving the divertor slot region, towards the core plasma, compared to theELM-free plasma case. The time-integrated escape current, however, may not significantlyaffect core plasma high-Z contamination concerns, for a 1% ELM duty factor, but may be anissue for higher frequency ELMs. In general, the modeling results appear favorable for effectivetesting of the SAS-VW divertor in DIII-D, and extrapolation to innovative divertor designs infuture ITER-like and DEMO fusion devices.