Implosion and X-Ray Emission in Radial Wire Array Z-Pinches

Abstract

Summary form only given. We present detailed measurements of the implosion and X-ray emission mechanisms of radial wire array z-pinches - array configurations where the wires stretch radially outwards from a central cathode. Initially the wires ablate, then an implosion begins, starting close to the cathode where the global magnetic field is highest. Implosion continues as bubbles of plasma being accelerated above the cathode where they collide forming a highly emitting column. In the radial configuration emission from the snow-ploughing of ablated plasma can be more easily separated from that of the stagnating plasma column than in standard cylindrical wire arrays, allowing the different physical processes that determine emission to be examined. The scaling of power and yield with array configuration is explored in order to test whether radial arrays can provide a compact source for the energisation of small scale hohlraums on larger facilities. In addition to fine metallic wires, solid metal foils have also been imploded. The gross dynamics of foil experiments are similar to those with wires - with plasma first being observed to be ablated from the foil and then an implosion and stagnation occurring close to the cathode. Differences in the use of foils and arrays will be highlighted, and current stratification explored.