Modeling of Surface Morphological Evolution of Plasma-Facing Tungsten*

We have developed an atomistically-informed, continuous-domain model to describe the surface morphological evolution of plasma-exposed tungsten (W). Based on this model, we have conducted self-consistent numerical simulations of the dynamics of the helium plasma-irradiated W surface morphology and carried out systematic comparisons of the simulation results with experimental measurements. The surface morphology predicted by our simulations is in good qualitative agreement with the experimental observations for the early stage of nanotendril formation on the W surface, a precursor to fuzz-like surface growth. Additionally, quantitative comparisons between the experimental data and the simulation results show that our model predicts satisfactorily the growth rate of the nanotendrils and provides reasonable estimates for the nanotendril width and arrangement on the W surface. Furthermore, we have investigated the dependence of the nanotendril width and arrangement on the W surface on the He fluence and surface temperature.