Staged Z-Pinch Experiments on Zebraand Simulations Using Different Gas Shells

Recent experiments at the Nevada Terawatt Facility at UNR show evidence of uniform compression of a deuterium plasma target compressed by a high-Z, Argon or Krypton gas-puffed liner. Pinch stability is improved by seeding the implosion with a 0.1-0.2 T axial magnetic field. Implosion dynamics and stagnation conditions are also studied computationally with the radiation-MHD code MACH2, using in itial conditions similar to those in the experiment. Simulations show that magnetic field diffuses through the outer shell and piles up at the interface providing narrow profile, high intensity current that Ohm-icly preheats the target. This secondary piston launches a shock wave in the target plasma that heats the several 100 eV. Finally, the preheated target is adiabatically compressed to stagnation. Simulations show: (a) more pronounced preheating with Kr than Ar, (b) the axial magnetic field is compressed only in the shocked target and in the liner plasma, providing greater magneto-Rayleigh-Taylor mitigation during run-in compared to the self-similar model. For typical Ar liner on D target experiments we measured neutron yield up to 2x 10
⁹
and for Kr liner, up to 9x 10
⁹
.