Formation of surface microcracks and ejection of particles in vacuum under irradiation of aluminum-magnesium alloy in a Plasma Focus facility

It was found that particles of the metal are ejected in vacuum during the formation of microcracks in a film on the surface of a model alloy of the aluminum-magnesium system (AMG type) under the influence of pulsed beam-plasma flows with a power density q ~ (106 – 5·107 W/cm2) in a plasma focus setup. The formation of microcracks in the surface film of refractory aluminum oxide (Al2O3) occurs due to the processes of its sputtering, mechanical action of pulsed energy flows and thermal stresses arising in the surface layer. Ejection of alloy particles through microcracks in the oxide film is observed after melting of the surface layer of the alloy at q > 107 W/cm2. The possible influence of such effect on the process of ejection of dust particles in thermonuclear fusion facilities is noted.