Erosion of a Smooth First-Wall System for a Compact Fusion Ignition Experiment

Accurate estimates of first-wall erosion in a compact fusion ignition experiment are important for the design of the first-wall system and its maintenance. Because of maintenance requirements and thermal response considerations, a smooth wall represents a good candidate for the first-wall. This type of wall is considered in an analysis of first-wall erosion in the IGNITEX high-field ignition tokamak. A poloidal model of the scrape-off layer is used with a new sputtering model to investigate the distribution of first-wall erosion and impurity penetration into the plasma. Estimates of erosion values at the wall during disruptions are calculated both with and without vapor. Vapor shielding effects are found to be significant. The effect of the thermal quench duration is analyzed and various low Z first wall materials are considered.