Publications / SAND Report

Towards Multifluid Multiphysics Continuum Plasma Simulation for Modeling Magnetically-driven Experiments on Z}

Shadid, John N.

Magnetically driven experiments supporting pulsed-power utilize a wide range of configurations, including wire-arrays, gas-puffs, flyer plates, and cylindrical liners. This experimental flexibility is critical to supporting radiation effects, dynamic materials, magneto-inertial-fusion (MIF), and basic high energy density laboratory physics (HEDP) efforts. Ultimately, the rate at which these efforts progress is limited by our understanding of the complex plasma physics of these systems. Our effort has been to begin to develop an advanced algorithmic structure and a R&D code implementa- tion for a plasma physics simulation capability based on the five-moment multi-fluid / full-Maxwell plasma model. This model can be used for inclusion of multiple fluid species (e.g., electrons, multiple charge state ions, and neutrals) and allows for generalized collisional interactions between species, models for ioniza- tion/recombination, magnetized Braginskii collisional transport, dissipative effects, and can be readily ex- tended to incorporate radiation transport physics. In the context of pulsed-power simulations this advanced model will help to allow SNL to computationally simulate the dense continuum regions of the physical load (e.g. liner implosions, flyer plates) as well as partial power-flow losses in the final gap region of the inner MITL. In this report we briefly summarize results of applying a preliminary version of this model in the con- text of verification type problems, and some initial magnetic implosion relevant prototype problems. The MIF relevant prototype problems include results from fully-implicit / implicit-explicit (IMEX) resistive MHD as well as full multifluid EM plasma formulations. Acknowledgements The authors would like to acknowledge the help of Wyatt Hagen, Jesus Bonilla, Richard Kramer, Duncan McGregor, Allen Robinson, Greg Radtke, Matt Bettencourt, Kieth Cartwright, Kris Beckwith, Chris Jennings, Russel Hooper, and Jose Pacheco for helpful discussions on the form of the multifluid plasma model, verifica- tion problems, and application prototypes. John Carpenter for help with integrating the UTRI EoS capability and for delivering specific EoS models for our use.