Radial foil Z-pinch experiments on the MAGPIE generator*

The dynamics of plasma formation in a radial foil Z-pinch are presented. The experimental setup consists of a $\mu $m-thick aluminum disc held between two concentric electrodes and subjected to a 1.4 MA, 250 ns current pulse from the MAGPIE generator. The JxB force acts on the ablated plasma from the foil forming a region of enhanced density on the axis. This precedes the pinching of plasma from current-driven magnetic ``bubbles''. The interaction of these features with an argon ambient (N$\sim $10$^{16-17}$ cm$^{-3})$ from a supersonic gas nozzle (Mach$\sim $9), particularly the formation of several shock structures will be presented and discussed.