Sputtering Performance of a Pumped Limiter for an Ignition Tokamak

The sputtering performance of a pumped limiter for a near-term ignition tokamak was analyzed using the REDEP computer code. Erosion, redeposition, surface shape and heat flux changes with time, and plasma contamination issues were examined. A carbon-coated limiter was found to give acceptable sputtering performance over a typical device lifetime if, and only if, acceptable redeposition properties of carbon are obtained. Beryllium is a good backup material in the event carbon is not acceptable.