Experiments on plasma dynamics of electrical wire explosion in air

Abstract

Besides a typical high-density plasma source, electrical explosion of conductors is also indispensable in switches, nanomaterial synthesis, shock-wave sources, etc. In this paper, an experimental study regarding plasma dynamics of electrical wire explosions (μs-timescale) is presented, with spatiotemporal resolved diagnostics. Pure Cu/Ni wire and Cu-Ni alloy wire were used and compared. The alloy wire usually has a higher resistivity, resulting in a higher initial energy deposition (heating) rate. Abel inverse transformation indicated that the plasma radiation focussed on the outer region of the discharge channel for the alloy wire. In addition, the metallic vapour determined by the material properties had a considerable influence on the plasma process and resulting nanomaterials. In particular, both transverse and axial-layered structures were observed in alloy wire vapour. In addition, for the first time, the expanding arc-like plasma of explosion products was understood and examined from aspects of material properties and energy relaxation. The later stage of wire explosion resembled the state of regular metal vapour arcs under 1 MPa pressure. Finally, the core factor for the fast energy deposition stage of wire explosion was ascertained. Correlations between pre-exposition circuit parameters and post-explosion dynamic effects were found, which is significant for practical applications.