Shock-induced conductivity waves in a conductor placed in an external magnetic field

Electromagnetic processes in a shock-compressed conductor placed in an external magnetic field are analyzed. The motion of the shock wave results in the appearance of two countercurrents that flow ahead of the shock front in the uncompressed-material region and near the back boundary of the conductor, respectively. The observed electromagnetic pattern is due to current diffusion and convective transfer in the conductor. When the shock wave arrives at the conductor, the absolute value of the currents grows tending (in the case of a considerable sample thickness) to a constant determined by the condition of magnetic-field “trapping” by the material. In this case, the electromagnetic pattern is characterized by two space-separated current waves: a stationary steady wave moving along the uncompressed material with phase velocity and a nonstationary diffusion wave which originates at the back boundary of the conductor. Voltage recordings at one of the sample surfaces can be used to determine the material parameters in a compressed state.