Modelling of tungsten sputtering by argon particle bombardment on a fuzzy surface

Abstract

• The physical sputtering of tungsten fuzz by the Ar ions have been investigated by SURO-FUZZ. • The detailed studies of the impacts of Ar incident energy and fuzzy layer thickness on tungsten physical sputtering have been conducted in this work. • The physical sputtering yield is in reasonable agreement with measurements. The physical sputtering yield of a tungsten (W) fuzzy surface by argon (Ar) plasma bombardment was measured in the linear plasma device PISCES-B, which showed an evident reduction in the physical sputtering yield on the fuzzy surfaces in comparison with a smooth surface (Nishijima D . et al 2011 J. Nucl. Mater. 415 S96). In order to reproduce and explain this phenomenon, dedicated modelling of W physical sputtering on smooth and fuzzy surfaces by Ar bombardment has been performed with the three-dimensional kinetic Monte Carlo code SURO-FUZZ. According to a measured porosity distribution, W fuzzy surface morphology is constructed in our simulation, on which physical sputtering, trapping and escaping of W atoms under Ar bombardment are simulated with SURO-FUZZ. Detailed comparison between simulation and experiment reveals that microscopic structures of W fuzzy nanofibers play a critical role in the trapping of W atoms and hence in the resulting physical sputtering yield. For the same porosity distribution, the simulated physical sputtering yields of W fuzzy surface morphology with shallow valleys are higher than the measured values, while W fuzzy surface structure with deep and narrow slots results in a lower physical sputtering yield compared to the experimental data. The good agreement between simulation and experiment can be attained for W fuzzy surface morphology with deep and relatively open recessions.