Measurement of electrical conductivity of condensed substances in shock waves (Review)

Available experimental techniques of electrical conductivity measurements under strong shock compression are analyzed. Dielectric-semiconductor, dielectric (semiconductor)-metal, and metal-metal (semiconductor) transitions are considered. Methods and schemes of contact and contactless measurements in inert and electrically active media, implemented by various authors, are discussed. In-depth analysis of measurement circuits, two-dimensional and three-dimensional modeling of currents, fields, and hydrodynamic flows, passing from the electric engineering model to the field electromagnetic model, and allowance for transitional electrodynamic processes have contributed to the significant recent improvement of the time resolution and to extending the range of conductivity registration under shock compression. A typical feature of new techniques is solving a differential equation for the electrical circuit or finding electrical conductivity by solving an inverse boundary-value problem for the magnetic diffusion equation. In particular, the problem of electrical conductivity registration on dielectric (semiconductor) – metal transitions, which has been known since the 1950s, is solved in this manner. Difficulties, constraints, and unsolved problems of experimental techniques are discussed.