Experimental research of electrical conductor explosion in the current skinning mode

Abstract

The research of plasma formation on the surface of different metals at the rise rate of the magnetic induction up to 1011 T/s is of interest in terms of energy transport efficiency in the vacuum transmission lines of multi-megaampere pulsed power generators. Such generators with a Z-pinch radiating load are the candidates for realization of inertial confinement fusion. The formation of plasma on the conductor surface occurs due to the electrical explosion in the current skinning mode. In this mode the time of the energy input into a conductor is less than the diffusion time of the magnetic field. From microsecond experiments with megagauss magnetic fields, it is known that the destruction of a conductor occurs in the field with magnetic induction of a few megagausses. The amount of available experimental data on plasma formation in fast-rising megegauss magnetic fields is very limited. Therefore, the experiments on the explosion of cylindrical conductors in the current skinning mode at the rise rate of magnetic field on the conductor surface of (0.8÷1.5)·1010 T/s were carried out on the MIG pulsed power generator (current 2.5 MA, rise time 100 ns). The diameters of conductors made of aluminum, copper and titanium were (1÷3.5) mm. The instant of plasma formation on the conductor surface was registered by detectors of vacuum ultraviolet radiation. We have concluded that in the current skinning mode the some threshold value of the magnetic induction exists and this is that value when the magnetic energy density is enough close to the sublimation energy of the material.