Discharge phenomena associated with a preheated wire explosion in vacuum: Theory and comparison with experiment

Abstract

This paper presents the experimental and simulation results of electrical explosions of preheated tungsten wires at a current rise time of several tens of nanoseconds and at a current density of ∼108A∕cm2. The electrical characteristics of wire explosion (WE) were measured. The image of a wire during the electrical explosion was obtained with the help of a framing camera. The proposed magnetohydrodynamic (MHD) model takes into account different stages of WE, namely, the wire heating and vaporization, the phase transition, and the shunting discharge. Two different mathematical approaches were used for WE simulation at different stages. At the first stage, the simulation included a code describing the wire state. At the second stage, the shunting discharge was simulated together with the wire state. The simulation code includes the set of MHD equations, the equilibrium equation of state (density and temperature-dependent pressure and specific internal energy), electron transport models (density and temperature-dependent electrical conductivity and thermal conductivity), and electric circuit equations. Thermionic emission and vapor ionization initiate the plasma layer, which develops around the wire core and supports the shunting discharge. The calculated waveforms of the wire voltage and current, as well as the velocity of the expanding plasma, are in a good agreement with the experimental data.

Temporal shock wave analysis produced by copper exploding wires in air at atmospheric pressure

“…Because the shock wave generated has rich information about the shock wave generator system, different wire materials, dimensions, and surrounding media were studied in the past. [14][15][16][17][18] Here, we focus the study on a copper exploding wire at atmospheric pressure. The diameter of wire and charged voltage of the electrical system are used simultaneously as parameters in these experiments.…”

Numerical simulation on the influence of some parameters on wire electrical explosion based on a 0D model

“…A commonly used circuit configuration of single wire electrical explosion [5] was adopted with discharging current supplied by a pre-charged capacitor (C). Other circuit parameters include the inductance (L c ), and the resistance (R c ) of the source and circuit, and resistance (Rg) and inductance (Lg) of the discharging gap, which are influenced by gap state.…”

“…In prepulse stage of these experiments, plasma layer was formed and the current rise rates were tens of A/ns. To study the WEE in this stage, some small-size facility [4][5][6][7] were designed to study this phenomenon in single wire explosion.…”

“…With respect to single wire explosion, a 0D MHD model has been developed [5]. Processes of energy deposition and plasma layer expansion were calculated in the condition of current rise rate of 10-30A/ns.…”

“…Processes of energy deposition and plasma layer expansion were calculated in the condition of current rise rate of 10-30A/ns. Based on the model developed by Beilis and co-workers [5], this work analyzed the behavior of single wire explosion, and the influences of circuit and particle density. A comparison under same condition was made between our simulation and existing results.…”