Advances in Large Diameter Gas-Puff Nozzles for Long-Pulse Z-Pinches

Summary form only given. Nozzles for high current, short implosion time (<100 ns) Z-pinches have historically produced a single thin shell of gas, typically a few cm in diameter. As interest in longer implosion time drivers has increased in the last several years, larger diameter nozzles have been developed. In order to minimize the effects of Rayleigh-Taylor instabilities, distributions consisting of multiple shells of gas or nearly uniform fills have been used. We report here on the continued development and testing of a 12 cm diameter nozzle that consists of 2 shells and a central jet. We will discuss the dependence of the yield and the plasma parameters on the initial gas profile, presenting recent results.