Exposure of CFC-materials to high transient heat loads in the TEXTOR tokamak

Abstract

Transient high heat flux events like ELMs, vertical displacement events and disruptions can cause the thermal ablation of plasma facing material. Until now experimental work in this field had been carried out by 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 insertion of the material over a distance of 9 cm into the edge plasma for a duration of 80 ms. The results of in-situ diagnostic measurements and of the post-experiment examination of the specimens are compared with a reference experiment by electron beam and with numerical analyses. Results indicated that the heat flux to the probe surfaces and the probe erosion is much lower than expected.