Formation of Surface Microcracks and Ejection of Particles into a Vacuum under Irradiation of an Aluminum–Magnesium Alloy in the Vikhr’ Plasma Focus Setup

It is found that metal particles are ejected into a vacuum upon the formation of microcracks in the surface film of a model alloy of the aluminum–magnesium system (AMG type) under the influence of pulsed plasma beam flows with a power density of q ~ 10 6 –5 × 10 7 W/cm 2 in a Vikhr’ plasma focus device. The formation of microcracks in the surface film of refractory aluminum oxide (Al 2 O 3 ) is associated with sputtering processes, the mechanical impact of pulsed energy flows, and thermal stresses arising in the surface layer. The ejection of alloy particles through microcracks in the oxide film is observed after melting of the surface layer of the alloy at q > 10 7 W/cm 2 . The possible influence of such an effect on the process of ejection of dust particles in thermonuclear fusion facilities is noted.