High heat flux simulation experiments with improved electron beam diagnostics

Plasma facing materials such as beryllium, carbon or tungsten are subjected to intense heat loads during off-normal plasma operation. To simulate thes e events, electron beam experiments are performed routinely to investigate the thermomechanical performance of the materials. In these tests, main emp hasis has been laid on the material damage such as melting, cracking, and d egradation of the materials' properties. On the other hand, severe thermal loads are also associated with the release of particles from the loaded sur face (metallic droplets or carbon dust) which might contaminate the plasma in future fusion devices. To investigate these phenomena in high heat Bur s imulation tests, extensive diagnostics are required to evaluate the actual material loading and to characterize the resulting material damage. Among t hese are measurements of the electrical current through the test coupons an d high-speed IR pyrometry. (C) 2000 Elsevier Science B.V. All rights reserv ed.