High-temperature transient surface heating experiments on carbon in Be-seeded deuterium plasmas

A beryllium-seeded deuterium plasma and transient surface heating system is used in PISCES-B to investigate mixed-material erosion and redeposition properties of ITER relevant divertor materials. This heating can be used to investigate the effects of thermal cycling in plasma facing components expected during ELMs in ITER-like devices. An experimental investigation of the effects of thermal cycling on Be films on graphite has been conducted. It has been shown previously that Be film growth on C can form carbide layers that reduce the chemical erosion of C during deuterium ion bombardment. Results from heat cycling on the chemical erosion and on deuterium retention in C targets up to 1200 °C have shown an enhancement in layer formation. In this report, the temperature range was extended to above 2100 °C, the expected dissociation temperature of Be2C. It has been found that even heat pulses up 0.1 s long to temperatures above this dissociation temperature, Be2C layer formation is enhanced by the thermal cycling. This work was supported by Grant DE-FG02-07ER-54913 from the US DoE.