Surface erosion under ion bombardment: Case studies in space weathering and nuclear fusion research

Abstract

Bombardment of surfaces with energetic atoms or ions results in material erosion (sputtering), particle implantation and changes in surface morphology as well as changes in elemental composition. Most laboratory experiments on sputtering have so far focused on ideally flat and monoelemental samples. However, realistic materials such as the walls of fusion reactors or the rocky surfaces of moons or airless planets are rough and consist of compounds of several different elements. In addition, the surface morphology and chemical composition typically change dynamically with prolonged exposure to plasma or solar wind ions (material mixing, re-deposition of sputtered material, etc). Recently, three-dimensional versions of modern computer codes based on the binary collision approxi- mation, such as SDTrimSP-3D and TRI3DYN, have become available, which are able to simulate sputtering processes on such realistic 3D surfaces. In this talk several experimental case studies will be presented which show how well it is already possible to achieve excellent agreement between simulation and experimental results. This is demonstrated with examples from (a) plasma-wall interaction in fusion plasmas and (b) solar wind- induced space weathering of Mercury analogue materials and Lunar dust from the Apollo XVI landing site.