Influence of Pulsed Beam-Plasma Impact on a Tungsten–Copper Pseudoalloy in the Plasma Focus Device

The results of a study of the combined effect on the W–Cu pseudoalloy of pulsed flows of deuterium ions with a power density of q_i ≈ 1 × 10⁹ W/cm² at an exposure duration of τ_i = 20 ns and deuterium plasma with parameters q_pl ≈ 1 × 10⁸ W/cm² and τ_pl = 20 ns generated in the “Vikhr” Plasma Focus installation are presented. It is shown that in the implemented mode of irradiation the nature of the damage to the surface layer of the tested material depends on the state of the surface of the irradiated samples and the number of pulsed impacts of energy flows. The impact of pulsed irradiation on the polished surface of pseudoalloy samples leads to the appearance of extended copper drops on the tungsten surface and to the formation of many pores, which are observed both in Cu drops and in the W matrix. In addition, microcracks appear on the W surface, as well as islands of a copper film of arbitrary configuration. Repeated irradiation of samples of the studied material with an unpolished surface leads to the formation of chains of tungsten droplets located in the upper parts of extended ridges formed during grinding of the original samples. Bursting bubbles are also visible on the irradiated surface, which arise as a result of the boiling of copper inclusions and a copper film deposited on tungsten. Clusters of such bubbles are often localized along ridges on the tungsten surface. The results obtained are discussed using numerical calculations and analysis of the thermal effect on the considered pseudoalloy under pulsed irradiation.