PPPS-2013: The role of shock waves in a Z-pinch

Summary form only given. A Z-pinch liner, imploding onto a plasma target, provides a step-wise, staged-energy transfer to the target.
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For high-gain fusion, simulations were performed using the 2-1/2 D MHD code MACH2. The requirements are for: an initial radius of a few mm, in order to achieve a stable implosion; a suitable thickness for the liner, to promote radial-current transport and current-amplification in the target plasma; and an appropriate initial distribution of the material-densities, to promote target pre-heating by shocks and adiabatic compression leading to a high-energy-density, magneto-inertial implosion. Simulations clarify the role of shock-heating and magnetic-field transport. Since the shock velocity is smaller in the liner than in a low-Z target, a shock front forms at the interface. This promotes target preheat and a more effective adiabatic compression at the final stage, vs. simulations performed for a high-Z target, where a shock front does not develop. Thus, the radial-compression ratio needed to achieve a high-energy density implosion, is greatly reduced compared to the case without shock pre-heat. The pinch parameters simulated were those for: a) ZEBRA, a TW pulser at the University of Nevada, Reno and b) the Z Facility, a 250 TW pulser at Sandia National Laboratories, Albuquerque, NM.