Influence of electronic effects on the surface erosion of tungsten

Abstract

Tungsten is a strong contender for a plasma-facing material in future fusion power plant designs, and the material of choice for the divertor of ITER, due to its high melting point, thermal conductivity, and resistance to sputtering erosion. Sputtering erosion is a major concern for plasma-facing materials because sputtered atoms could enter the plasma and result in cooling. Atomistic modeling, using molecular dynamics, has previously been successful in identifying fundamental mechanisms of surface damage caused by ion bombardment. The damage has been found to be particularly sensitive to the rate of energy dissipation but energy transport is not well described in classical molecular dynamics simulations of metals. We present a methodology for including a realistic description of electronic energy absorption, transport, and redistribution in molecular dynamics simulations of self sputtering. The results for three different 5 keV self-sputtering events are presented for four distinct thermal transport models. The results demonstrate the sensitivity of surface damage to the model used to describe the electronic thermal transport.