One-Dimensional FLASH Simulations of a Gas-Puff Staged Z-Pinch

The staged Z-pinch (SZP) is an alternative, pulsed-power–driven magneto inertial fusion concept under development at Magneto-Inertial Fusion Technology, Inc. (MIFTI). While there have been several SZP variants proposed in the literature, a common property is the use of a high atomic number liner. In this talk we focus on FLASH simulations of a gas-puff Xe liner, a variant that has been referred to as SZP1 in the literature. The initial conditions and parameters used in the simulations we present differ in two key aspects compared to previous publications: (1) the use of a more-realistic double-Gaussian initial density profile, and (2) the use of a circuit model that can represent the pulsed-power Z machine at Sandia National Laboratories. Since MIFTI has used the MACH2 code for many of their calculations, we include code-to-code comparisons of FLASH and MACH2 on this new SZP1 setup. For the comparison runs, the two codes employ the same tables for the equation of state, ionization, and opacities, limiting the FLASH runs to gray opacities, i.e., single-group radiation diffusion, to match MACH2. We also present a FLASH run with a more-realistic multigroup diffusion configuration, with 40 energy groups and updated transport coefficients. The results show how the problem is affected by the choice of transport coefficient and that the SZP is worth further study as high convergence ratios and temperatures are achieved.



This material is based upon work supported by the Department of Energy (DOE) National Nuclear Security Administration (NNSA) under Award Numbers DE-NA0003856 and DE-NA0003842, the U.S. DOE Advanced Research Projects Agency-Energy (ARPA-E) under Award Number DE-AR0001272 and the U.S. DOE NNSA under subcontracts no. 536203 and 630138 with Los Alamos National Laboratory, subcontract B632670 with Lawrence Livermore National Laboratory.