Implementation and Verification of Braginskii Viscosity in the FLASH Code

The inclusion of ion viscosity when solving a radiative magnetohydrodynamic ansatz to simulate high-energy-density physics (HEDP) laser-driven plasma experiments is key to correctly capturing momentum diffusion and the flow’s fluid Reynolds number (Re). When the diffusion time scale becomes comparable to the advection timescale, ion viscosity will impact flow dynamics and transport properties. Here we present the numerical implementation of Braginskii ion viscosity[1] in the FLASH code. We detail the numerical implementation that couples with the flux-based viscosity module in the code and show results from an array of verification benchmarks. The inclusion of a realistic ion viscosity significantly broadens the range of plasma regimes where FLASH can be applied and enhances the fidelity of HEDP simulations where Re . 

 

The Flash Center acknowledges support by the U.S. DOE ARPA-E under Award DE-AR0001272, the NSF under Award PHY-2033925, and the U.S. DOE NNSA under Awards DE-NA0002724, DE-NA0003605, DE-NA0003842, DE-NA0003934, and Subcontracts 536203 and 630138 with LANL and B632670 with LLNL. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0003856.