Experimental and numerical study of a wire-explosion-pos dynamics

Summary form only given. A design of fast current switch using wire explosion is a problem of studying by our team experimentally and numerically. The main unit of the experimental setup represents itself two coaxial cylindrical electrodes connected by a thin single wire which is exploded by the current pulse. In the experiments a current with the amplitude up to 80 kA and rise time of 7 μs flowing through the 4-mm tungsten wire. Plasma generated by exploded wire fills the inter-electrode space "circularly" owing to the interaction with magnetic field (up to 30 kG) produced by an external source and directed along the electrodes. The setup construction allows us to change the amplitude of current flowing between the electrodes and to measure the total resistance of inter-electrode volume. Therefore we can study a plasma dynamics by varying the current value. In our experiments the current amplitude is changed in a rather wide range of 10-80 kA, and a current rise time is changed from 10
⁹
to 10
¹⁰
A/s. The experimental data are compared with those obtained via computer simulation carried out by means of the radiative magnetohydrodynamic code MARPLE3D (KIAM RAS). W e studied 3D plasma dynamics numerically (i) at a stage of a wire explosion and filling of the inter-electrode gap by plasma, and (ii) a stage of a plasma switch functioning. Numerical simulations allow to estimate a time which need to fill the volume between the coaxial electrodes with the plasma generated from the wire and to study the switch dynamics dependence on the hydromagnetic instability as well as on the Hall effect. The numerical data correlates with experimental results. The main problems we discuss are: (i) what are possible reasons of the rapid decreasing of the switch resistance and (ii) how we can maintain an appropriately high resistance of the switch during the time needed for its applications.