Effects of Low Energy and High Flux Helium/Hydrogen Plasma Irradiation on Tungsten as Plasma Facing Material

Abstract

The High-Z material tungsten (W) has been considered as a plasma facing material in the divertor region of ITER (International Thermonuclear Experimental Reactor). In ITER, the divertor is expected to operate under high particle fluxes (>1023 m-2 s-1) from the plasma as well as from intrinsic impurities with a very low energy (<200 eV). During the past dacade, the effects of plasma irradiation on tungsten have been studied extensively as functions of the ion energy, fluence and surface temperature in the burning plasma conditions. In this paper, recent results concerning blister and bubble formations on the tungsten surface under low energy (<100 eV) and high flux (>1021 m-2 s-1) He/H plasma irradiation are reviewed to gain a better understanding of the performance of tungsten as a plasma facing material under the burning plasma conditions.