Staged Z-pinch experiments and modelling on the 4 MA pulsed power generator Double Eagle

Staged Z-pinch is a potential high-energy gain fusion concept where a high atomic number liner implodes on a fusible target utilizing pulsed, multi-MA current source. Over the past several years this concept has been studied at 0.5MA and 1.0MA facilities using krypton or argon gas puff liners and a deuterium target. Consistent thermonuclear neutron yield of 10¹⁰ per shot was measured at the 1MA Zebra facility [1]. Here we present the first results of experiments on the 4MA Double Eagle pulsed power generator at L3Harris, using 3cm radius nozzle. The pinch stability was monitored with a time gated 4 frame XUV camera, and with a time integrated X-ray pinhole camera. The neutron yield was measured with a pair of LaBr₃ activation detectors and the neutron isotropy was assessed with a set of neutron time of flight detectors. Modeling with the MACH2 and HYDRA codes suggests that using a 3cm nozzle for liner gas injection generates stronger shock waves compared to the 2cm nozzles used previously. In this experiment the shock waves preheat the target plasma up to keV temperatures which creates a counter balancing thermal pressure on the liner plasma, thus limiting the growth of the Rayleigh Taylor instability, and providing stable final pinch implosion. Experimental and modeling results supporting these findings will be presented.

[1] E. Ruskov et al, “Measurements of neutrons created in a Staged Z-pinch with krypton liner and deuterium target at a 1 MA pulsed power generator”, submitted to IEEE Transactions on Plasma Science