Simulation of ITER edge-localized modes' impacts on the divertor surfaces within plasma accelerators

Experimental simulations of ITER transient events with relevant surface heat load parameters (energy density and pulse duration) as well as particle loads were performed with a quasi-steady-state plasma accelerator Kh-50 and pulsed plasma guns. Additional shielding was observed during irradiation of the combined carbon-tungsten (C-W) surface. An evaporated C cloud protects W from evaporation even at an energy density of 2.4 MJ m(-2) in impacting plasma. The spectrum of tungsten and parameters of shielding layers were found under powerful exposure of the tungsten surface. An influence of material modification through plasma exposures on cracking thresholds of tungsten is emphasized. It was found that increasing the number of exposures to more than 20 plasma pulses of 0.25 ms in duration shifts the energy threshold for crack development from 0.3 down to 0.2 MJ m(-2). Differences in the evolution of tungsten substructure after exposure to helium and hydrogen plasma streams of different duration are also analyzed.