Temporal evolution of the hydrodynamic instability of the boundary between the dense core and the plasma corona during nanosecond explosion of wires

We report the results of investigations of the interaction of a plasma corona with a dense, cold core formed on the discharge axis in the initial stage of the nanosecond electrical explosion of metal wires. The internal structure of the dense core and the dynamics of processes occurring in it were studied by a specially developed method of multiframe x-ray shadow photography. The large observed amplitudes of the disturbances of the boundary between the dense core and the Z-pinch corona, which are comparable to the core radius, are attributed to the development of Rayleigh-Taylor and Kelvin-Helmholtz hydrodynamic instabilities. (C) 1998 American Institute of Physics. [S0021-3640(98)00308-9]