Sputtering of tungsten surfaces by different ion types: A molecular dynamics study

Sputtering of the wall material in fusion reactors is an undesired phenomenon, as it will affect the performance of the reactor. Tungsten is the material chosen to be the plasma-facing material in many of the proposed fusion reactors. Using molecular dynamics simulations, the factors influencing tungsten sputtering yields were investigated, focusing on ion energy, incidence angle, surface orientation, ion mass, and interatomic potential. The investigated ions were argon, neon, and tungsten, and the focus was on low-index surfaces. Higher ion energies significantly enhance sputtering yields, while certain incidence angles maximize the tungsten sputtering yields. The surface orientation affects the yields, with the close-packed surface showing mainly the least sputtering. Tungsten self-sputtering was low at perpendicular impacts, due to sticking, but increased significantly once the incidence angle grew. Angular distributions of the sputtered atoms reveal that low-energy sputtering is sensitive to the ion type and the surface orientation, whereas high-energy sputtering results in a more uniform distribution. These findings enhance the understanding of ion surface interactions and can be used as input in larger-scale models to study the erosion of plasma facing components in future tokamaks. • Sputtering yields increase with ion energy, irrespective of the ion type. • The (110) surface exhibits the lowest sputtering yield, while the (100) surface shows the highest yield. • The effect of ion mass emerges at specific angles. • The angular distribution of sputtered tungsten deviates from a cosine distribution. • A distinction between the truly sputtered and reflected W ions is seen during self-ion irradiation.