STUDIES OF HIGH HEAT-FLUX AND RUNAWAY ELECTRON DAMAGE ON PLASMA-FACING MATERIALS

Two separate disruption damage mechanisms are analyzed; high heat-flux surface damage and runaway electron damage. A low-temperature high-density plasma source exposes samples to high heat fluxes typical in magnitude and duration to those experienced during the thermal dump phase of a disruption. The vapor shield phenomena occurring at ablative surfaces is thus verified by comparisons of experimental data with quantities predicted by code analysis. Extensive 3-D computer modeling of runaway electron damage reveals that electron energy, electron incident angle, and material stopping power are key parameters in the amount of energy deposition in plasma facing components. For both damage mechanisms graphite appears to be a better material to resist disruption damage.