Liner on Target Gas Puff Z-Pinches with Different Gas Species on the CESZAR Linear Transformer Driver

Abstract

The gas puff Z-pinch 1 is a magnetic direct-drive plasma compression scheme with applications as an efficient X-ray or neutron source and for research on the fundamental physics of dense plasmas. Presented here are results of gas puff Z-pinch experiments on the CESZAR driver 2 (500 kA, 160 ns) with an annular liner imploding onto an on-axis target, where one or both species is D2. We investigate the effects of load material (D2, Ne, Ar, or Kr) on implosion dynamics, including stability and energy coupling, and on pinch performance. We show via self-emission and laser imaging that the inclusion of a central target jet improves pinch stability, and we discuss correlations between gas species and stability in liner-on-target implosions. Magneto-hydrodynamic simulations are used to infer values of plasma kinetic and internal energy, which are compared with experimental estimates. Pinch performance is quantified by measuring X-ray and neutron yield. Finally, we show that pinch reproducibility can be improved by pre-ionizing the gas before the main current pulse.