Sensitivity Analysis of Flyer Modeling in the FLEXO Extended-MHD Code

FLEXO (Flux-Limited Extended-MHD Ohm’s Law) is a next-generation extended- magnetohydrodynamics (MHD) discontinuous Galerkin code being developed at Sandia National Laboratories for modeling high-energy-density (HED) plasma in a pulsed-power device. We present recent results from simulations of a flyer plate typical of those used in dynamic compression experiments. The flyer is compressed and accelerated by an electromagnetic drive, and comparisons are made to existing simulation and experimental results. In one case, we examine sensitivity of beryllium flyer velocities, burn-through times, and other properties to the tabular conductivity model being used, where a set of conductivity tables has been generated using a Bayesian inference scheme, and we compare the sensitivities in FLEXO to those seen in existing MHD simulation results. In another case, we model a copper flyer and vacuum as separate materials, assessing how various aspects of FLEXO’s multi-material modeling affect the comparison with experimental and simulation results from another MHD code. Less diffusive choices of approximate Riemann solver for numerical flux, among other measures, have been shown to improve agreement.



Sandia National Laboratories is a multimission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525.



SAND No. SAND2025-08542A