Fully electromagnetic particle-in-cell simulations of a deuterium gas puff z-pinch

A deuterium gas puff z-pinch has been shown to be a significant source of neutrons. Early experiments measured neutron yields that were not thermonuclear in origin but likely driven by instabilities. Subsequent experiments including recent 15 MA experiments on the Z accelerator2 have suggested that the dominant process is thermonuclear. The neutron yield has been shown to scale strongly with current as Y_n ~ 14 assuming the production is a thermonuclear process. In this paper, we present 1D and 2D simulations of deuterium z-pinches with the hybrid, implicit fully electromagnetic particle-in-cell code LSP. LSP algorithms permit finite mean-free-path effects and charge separation. Calculated Y_n from a Monte Carlo treatment of D-D fusion reactions are compared with measurements and MHD simulation results. Initial ID simulation estimates of neutron yield using the simulated plasma characteristics from the compressed 445-mg mass deuterium pinch (9.5 keV ion temperature, 2.5 mm radius, 5 ns confinement time) driven by a 15-MA current (shot 1678 on Z) are in reasonable agreement with the measured yield. Mechanisms for nonthermal ion production will be investigated.