Experimental investigations on energy deposition and morphology of exploding aluminum wires in argon gas

Abstract

Experiments demonstrate a strong dependence of the energy deposition and morphology of exploding Al wires in argon gas on ambient pressures, charging voltage, and wire sizes. The specific energy deposition, before voltage collapse, increases with increasing ambient pressures and applied voltage but decreases with increasing wire sizes. The observation of the spatiotemporal distribution of exploding wires indicates that increased energy deposition suppresses the axial inhomogeneity, especially for large-sized wires, and improves the expansion velocity of the metal core. The expansion velocity of the wire core (100 μm in diameter, 2 cm in length) varies from ∼0.49 km/s to ∼2.3 km/s when the specific energy deposition increases from 1.95 eV/atom to 3.01 eV/atom. Decreased surrounding pressures also improve the expansion velocity. Furthermore, the analysis of photographs and emission spectrums demonstrates that the surrounding gases promote the formation of coronal plasmas when the pressure is no more than 50 kPa.