Influence of Erosion and Redeposition Processes on the Lifetime of Impurity Control Components: An Assessment for TiC Coatings

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Abstract
A REDEP computer-code-analysis has been performed for the transport, ionization, and redeposition of physically sputtered material in the boundary regions of the FED/INTOR tokamak. The analysis was performed for TiC as a candidate coating material for the bottom limiter and the divertor plate. This analysis provides the first assessment of the influence of preferential sputtering of TiC on sputter erosion and redeposition. The results indicate that at high edge temperatures, the different transport properties of the constituents causes significant differences in both the erosion and redeposition rates for the elemental constituents carbon and titanium. At low plasma edge temperatures, ≲ 50 eV, TiC is marginally acceptable, having a high gross erosion rate but a fairly low net rate.