EXPOSURE OF CFC-MATERIALS TO HIGH TRANSIENT HEAT LOADS IN THE TEXTOR TOKAMAK

Transient high heat flux events like ELMs, vertical displacement event s and disruptions can cause the thermal ablation of plasma facing mate rial. Until now experimental work in this field had been carried out b y exposing material specimens to heat loads by electron or laser beam or by tests in pulsed plasma accelerators. In the present work carbon specimens were directly exposed to intense plasma fluxes in the TEXTOR tokamak. The exposure was performed with a fast probe allowing the in sertion of the material over a distance of 9 cm into the edge plasma f or a duration of 80 ms. The results of in-situ diagnostic measurements and of the post-experiment examination of the specimens rue compared with a reference experiment by electron beam and with numerical analys es. Results indicated that the heat flux to the probe surfaces and the probe erosion is much lower than expected.