Wall damage due to oblique high velocity dust impacts

Abstract

Runaway electron termination on plasma facing components can trigger material explosions that are accompanied by the expulsion of fast solid debris. Due to the large kinetic energies of the ejected dust particles, their subsequent mechanical impacts on the vessel lead to extensive cratering. Earlier experimental studies of high velocity micrometric tungsten dust collisions with tungsten plates focused exclusively on normal impacts. Here, oblique high velocity tungsten-on-tungsten mechanical impacts are reproduced in a controlled manner by a two-stage light gas gun shooting system. The strong dependence of the crater characteristics and crater morphology on the incident angle is documented. A reliable empirical damage law is extracted for the dependence of the crater depth on the incident angle.