Assessment of plasma induced effects in crystalline and amorphous SiC as plasma facing material*

Modeling of plasma and ion irradiation of crystalline SiC and SiC based composites that are considered as alternative plasma facing materials for future pilot plant designs is performed to predict the effect of surface modification on material performance at various fusion reactor relevant conditions. The coupled ITMC-DYN and WBC packages integrate Monte Carlo and deterministic models of collisional and thermal particle/material interactions and the effects on material composition and erosion, and fuel retention. Several results of DIII-D and other ion beam experiments were used to benchmark simulations. The simulations predict conditions for transition of the crystalline surface to semi-crystalline and to amorphous phases due to collisional effects, preferential chemical bonding, and local particle redeposition. Significant displacement damage of the SiC surface, together with the high D content, results in changes in the equilibrium composition that leads to enhanced physical and C chemical erosion compared to the original crystalline surface. The performance of composite W-SiC materials was analyzed during normal and ELMs relevant fluxes and energies. The implications of using SiC as a potential plasma-facing material in fusion reactors are discussed.