An overview of sputtering-related processes occurring at mixed surfaces formed by simultaneous C+ and D+ irradiation of W

This paper reviews the interaction of carbon and deuterium ions with tungsten leading to the formation of mixed W–C–D surfaces. This projectile-target system is prone to synergistic effects, which are dependent on the presence of both projectile species. The erosion of the surface is governed by both kinematic effects and effects related to elevated surface temperature. It is found that the kinematics can be well described by available models of ion–surface interactions based on binary-collision approximations. The temperature-dependent processes include: chemical erosion, diffusion, erosion at elevated temperatures and radiation-enhanced sublimation. The effects of these processes, in particular their influence on the carbon content of the mixed W–C surface, have been studied experimentally. These experimental results and their implications for fusion applications are discussed here.