Retention, sputtering and surface chemistry at tungsten oxide surface facing deuterium plasma

Our study investigates the response of an oxidized tungsten surface to deuterium irradiation in the 5–120 eV impact energy range. Using the LAMMPS molecular dynamics tool and a ReaxFF force field, we analyze the retention, reflection, sputtering, and surface chemistry of oxidized layers at various thicknesses at room temperature. These layers, formed on the tungsten (001) surface through cumulative oxygen irradiation, show that most reflected D atoms and sputtered O atoms originate in the oxide ad-layer, not reaching the W-bulk. The retention probability of D atoms is notably high at the lowest energies, decreasing with energy and approaching metallic tungsten values at higher energies. Our findings, which are compared with those of metallic tungsten and existing literature, provide valuable insights into the behavior of oxidized tungsten surfaces under deuterium plasma irradiation, with potential applications in the design of plasma-facing components for fusion reactors.