Thermal Effects During Inertial Stretching of High-Gradient Conductive Rod with "Frozen" Magnetic Field

The study analyzed thermal effects at stretching of metal shape-charge jets caused by the longitudinal magnetic field in their material. The magnetic field amplifies in the course of stretching and generates circulation of vortex electric currents in a jet with production of Joule warmth. It is supposed that magnetic field in a jet is inherited from the field which is previously produced in a shaped charge liner before its explosion. The investigations are carried out by numerical modeling within a quasi-two-dimensional problem on inertial stretching of the high-gradient conductive rigid-plastic rod with the longitudinal magnetic field in its material. The purpose of the research was to find a possibility of increasing the ultimate elongation, as well as the penetrability of shaped-charge jets due to thermal softening of their material. Within the research we analyzed the effect of stretching electromagnetic forces on a jet in addition to heating. These forces arise at deformation of a jet with magnetic field and can lead to its destruction with radial dispersion of the material. Results of calculations suggest that indestructibility of the shaped-charge jets formed at a collapse of the conic liner with magnetic field can be kept if induction of the field produced in the liner does not exceed 0,1 T. At the same time the increase in ultimate elongation of a jet due to thermal softening of its material can reach 20 %. To enhance this effect, we suggest using an additional electromagnetic action on a shaped-charge jet by means of the solenoid placed before a shaped charge and producing on the jet motion trajectory the magnetic field with the orientation opposite to the orientation of the field in the shaped-charge liner

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