FLASH Simulations of a Gas-Puff Xe Liner Staged Z-Pinch

The staged Z-pinch (SZP) is a pulsed-power–driven magneto inertial fusion concept under development at Magneto-Inertial Fusion Technology, Inc. (MIFTI) [1,2]. There are now several SZP variations in the literature, but they all use a high atomic number liner. In this work, we focus on FLASH simulations of a low-density gas-puff Xe liner, driven by the pulsed-power Z machine at Sandia National Laboratories, imploding on DT fuel. This configuration differs from previous ones in a crucial way: the thermal losses in the fuel are dominated by thermal conduction rather than radiation. Therefore, if the fuel can be sufficiently magnetized, thermal conductivity and losses can be reduced. We include comparisons with results from the MACH2 code and show that there is a significant difference in fuel magnetization resulting in discrepancies in convergence ratios (CR) and stagnation. Despite this, both codes’ results are encouraging as fuel ion temperatures > 15 keV are achieved. The 1D FLASH results reach CR > 300, which is likely to be experimentally unattainable, and we see Rayleigh Taylor instability (RTI) growth in 2D simulations. We hypothesize that an applied axial magnetic field would help the fuel retain heat and improve stability, resulting in a CR that could be achieved experimentally.

[1] H. U. Rahman et al., Phys. Plasmas 26, 052706 (2019)

[2] E. Ruskov et al., Phys. Plasmas 28, 112701 (2021)