Addressing optimal underwater electrical explosion of a wire

The underwater electrical explosion of a wire in the timescale 10^-7-10^-6 s is characterized by different phase transitions at extreme values of deposited energy density, allowing one to obtain warm dense matter using rather moderate pulse power generators. In order to achieve maximal energy density deposition, the parameters of the wire and the pulse generator should be optimized to realize an overdamped explosion where most of the initially stored energy is delivered to the exploding wire during a time comparable with the quarter of the discharge period. In this paper, the results of 1D magneto-hydrodynamic modeling, coupled with the copper and water equations of state, of the underwater electrical explosion of Cu wires having an identical length and average current density but different discharge current rise time are analyzed and compared with those of a simplified model of a conductivity wave, the propagation velocity of which determines the mode of the wire's explosion. In addition, it is shown that in the case of extreme high current densities, a scaling from a single wire to a wire array having the same total cross-sectional area of wires cannot be used to obtain an optimal wire explosion.