DAMAGE OF REFRACTORY-METALS AND CARBON-BASED MATERIALS UNDER SIMULATION OF THE THERMAL INFLUENCE AT PLASMA DISRUPTION

Different materials (W, Mo, Ta, Ta + W and carbon-based materials) have been tested with respect to their damage behaviour (thermal erosion, melting, cracks formation) at conditions simulating plasma disruption. A quasistationary plasma accelerator (pulse duration of 0.1 ms and incident energy density of 5-12 MJ/m2) and a pulse electron accelerator (pulse duration of 0.05-0.2 ms and incident energy density of 1-5 MJ/m2) have been used for simulation of the thermal quench phase of plasma disruption. It was shown that for metals the absorbed energy is only 10% from the total one. The thermal erosion by plasma irradiation is many times lower than the predicted one. However under electron beam shocks the thermal erosion is comparable with the theory. A microstructural study has shown that tungsten exhibits the lowest crack formation resistance, on the other hand cracks in Ta and Ta + W alloy have not been observed. The thermal erosion of the tested carbon base materials in these experiments is smaller than predicted.