Sputtering from rough tungsten surfaces: Data-driven molecular dynamics simulations

Abstract

The sputtering of tungsten surfaces caused by hot plasma particles is an important process in fusion reactors where divertors are typically made of tungsten sheets. In this study, we present a molecular dynamics simulation strategy to investigate the sputtering yields of tungsten surfaces with geometrical defects. This should serve as a model for non-monocrystalline surfaces in general and could also be a rough model for nanoscale “fuzzy” layers, which are known to be formed by surface bombardment with energetic particles. Using a non-cumulative approach, we simulate the irradiation of tungsten surfaces with cone-shaped, cylindrical, and spherical defects by argon atoms. We analyze the sputtering yields as functions of particle energy and defect sizes. As a result, we find that surfaces with distinctly shaped defects always exhibit reduced sputtering yields, compared to smooth ones. We also investigate the angular distributions of sputtered particles and find them mostly to be in accordance with prior experimental and computational results.