Overview of Plasma Guns for PLX

Plasma guns are being developed for use on the Plasma Liner Experiment (PLX) located at LANL. The collapsing plasma liner will be formed via merging of 30-60 dense, high Mach number plasma jets ($n\sim 10^{16-17}$~cm$^{-3}$, $M\sim$10--35, $v\sim$50--70~km/s, $r_{\rm jet}\sim $5~cm) in a spherically convergent geometry. Small parallel-plate railguns are being developed for this purpose. Each gun will operate at $\sim$300-600~kA peak current, and launch up to $\sim$8000 $\mu$g of high-Z plasma (Ar, Xe) using a $\sim$50~kJ pfn. We are now successfully operating with very fast gas valve injection of Ar, and have already achieved good performance of 1200 $\mu g$ at 42 km/s, and 4000 $\mu g$ at 20-25 km/s at low current. Work is underway to increase both the mass and velocity using higher current. We describe experimental development of the minirailguns and their present and projected performance. We also discuss options for modest size coaxial guns that might achieve the same performance and provide additional control of the plasmoid structure.