The impact of surface morphology on the erosion of metallic surfaces – Modelling with the 3D Monte-Carlo code ERO2.0

Abstract

• The micro-scale model for simulation of the surface roughness effect on the erosion of PFCs and transport of sputtered material implemented previously into the 3D Monte-Carlo code ERO2.0 was applied for modelling of sputtering and deposition in the JET-ILW divertor conditions (smooth Tile 5 and rough Tile 6). • Micro-scale simulations have been conducted using two different assumptions: with and without tracing of incident plasma/impurity ions near the rough surface. Tracing of incident ions near the surface forms more realistic shadowing patterns than the case when this pattern is calculated based on magnetic field lines. • Simulations without tracing of incident ions have shown that surface roughness leads to a reduction of the effective sputtering yield by up to 50% depending on surface parameters. • Simulations including tracing of incident ions near the surface have confirmed decrease of the net erosion from the rough surface of the Tile 6 in comparison to the smoother surface of the Tile 5 by up to 50%. The roughness of metallic surfaces has a vital impact on the erosion of plasma-facing materials. Roughness determines the effective sputtering yield Y eff of the facing material. The angular/energy distribution of sputtered particles, and the spatial erosion and deposition distribution. The model for simulation the effect of the surface roughness was earlier implemented into the 3D Monte-Carlo code ERO2.0 and validated using results of ion beam experiments and experiments in the linear plasma device PSI-2. In the present study the developed ERO2.0 surface morphology model was applied to the JET-ILW tungsten (W) divertor consisting of smooth bulk W and W-coated CFC components. Influence of the surface roughness on the W erosion as well as on the transport of sputtered material in conditions of inclined magnetic field was investigated. Simulation results are in a good agreement with existing experimental findings.