Erosion and erosion products of tungsten and carbon-based materials irradiated by a high energy electron beam

A pulsed electron beam test was used to simulate the thermal response of plasma facing materials under high heat loads during plasma disruptions, particularly for relatively ‘long’ duration off-normal events such as plasma vertical displacement events. The erosion and erosion products of purified tungsten made by powder metallurgy (PM-W), W and B4C plasma sprayed coatings on CFC or copper and C/C composite were investigated. The time evolution of the target current indicates that the erosion products or screening clouds partly or completely shield the incident electron beam, leading to a reduction of the target current and changes in the target current profile. The weight loss of PM-W is smaller than that of the tungsten coating or C/C composite, which is in agreement with the erosion behavior. Erosion products indicate that evaporation is a major erosion mechanism of PM-W, and exfoliation and particle emission are the dominant erosion mechanisms of carbon-based materials and W plasma sprayed coatings.