DIVIMP Simulation of W Transport in the SOL of JET H-mode Plasmas
A. Järvinen, C. Giroud, M. Groth, K. Krieger, D. Moulton, S. Wiesen, S. Brezinsek and JET EFDA contributors This study provides predictions of tungsten contamination extrapolated from an inter-ELM phase of a high-triangularity, high-confinement, ITER-like wall reference plasma without impurity seeding in JET. The tungsten concentration for an equivalent ILW plasmas are predicted for low, medium, and high upstream densities, utilising the Monte Carlo trace-impurity code DIVIMP on background plasmas calculated with the 2-D fluid code EDGE2D/EIRENE. It is observed that operation at the low upstream density plasma with a sheath-limited scrape-off layer leads to core tungsten concentration of the order 10-5. Increasing the density leads to high-recycling scrape-off layer with adequate divertor retention to ensure acceptable tungsten core concentration below 10-5. Sufficient divertor retention is achievable when the peak target electron temperature, Te, is below 10eV. Achieving significant reduction of tungsten sputtering by multiple charged impurity species (e.g., Be2+, C4+) requires a peak target Te below 5eV, which requires strong divertor radiation achieved by impurity seeding in the ILW configuration.