Influence of cross-field drifts and chemical sputtering on simulations of divertor particle and heat loads in ohmic and L-mode plasmas in DIII-D, AUG, and JET using UEDGE

Abstract

Measurements and simulations with the UEDGE code of radiated power, and ion saturation currents and power loads to the target plates have been compared for density scans in ohmic and low confinement mode plasmas in DIII-D, ASDEX Upgrade, and JET. Simulations including cross-field drifts and assuming elevated chemical sputtering yields of 3%–4% move the numerical solutions closer to many of the measurements compared to omitting the drifts and using the published Davis–Haasz yields. Adopting these assumptions the simulations reproduce the measured currents and powers, and their functional dependence on upstream density to within a factor of 2, with the exception of the ion currents to the low field side target in ASDEX Upgrade and the high field side target in JET. The applicability of using enhanced sputtering yields is discussed by comparing measured and simulated emission from low charge state carbon in the divertor regions.