Advances in FLASH for magnetized HED processes

The FLASH code has recently undergone significant development to become a robust tool to model Z-Pinch implosions [1]. These simulations present many challenges due to their multiphysics nature and the presence of external magnetic fields. Pacific Fusion is further enhancing FLASH’s capabilities to ensure accurate models of targets for pulsed magnetic fusion energy. In this talk, we discuss various improvements to FLASH’s magnetized HED capabilities including improved opacity mixture strategies for multispecies plasmas; the implementation of per-species transport models and its effect on integrated simulations; and code enhancements for multi-regime thermal conduction models. We also present two comprehensive test cases to benchmark FLASH features against analytical solutions in relevant magnetized HED scenarios. First, we demonstrate the code's ability to capture the structure of radiative shocks in different regimes encompassing disparate optical depths [2]. In the second test case we assess the effect of thermoelectric terms in Nernst thermal waves in hot-spot MagLIF-like plasmas [3].

[1] E.C. Hansen et al., Phys. Plasmas 31, 042712 (2024).

[2] F. Garcia-Rubio et al., Phys. Rev. E 109. 065206 (2024).

[3] A.L. Velikovich et al., Phys. Plasmas 22, 042702 (2015).