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.

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Experiments were performed aimed at developing a plasma soft-x-ray source of small spatial dimensions. Radiating hot plasma was produced on compression of a metal vapor by a current pulse with amplitude I m = 215 kA and rise time T r = 200 ns. The metal vapor jet was generated by initiating a vacuum arc discharge (I m = 8.5 kA, T r = 6 µs) with an aluminum, tin, copper or iron cathode. Due to the small longitudinal dimension of the compressed Z-pinch, a single flash of soft x-rays was detected in the electrode gap. The least spatial dimensions of the radiating region were attained for aluminum and tin vapor pinches. When tin vapor was used, the diameter of the radiating region was 7 ± 2 µm and its height was 17 ± 2 µm. The x-ray pulse FWHM was 2-3 ns. The radiation power in the spectral range 1.56-1.9 keV was 10-15 MW for the aluminum vapor pinch and 5-10 MW for the tin vapor pinch.