Sensitivity of electrically exploding metal rods to tabular equation of state and electrical conductivity models in magnetohydrodynamic calculations *

The fundamental limits of high-current conduction in metals to large, fast current pulses are of interest to magnetically driven DMP and ICF. An electrically thick (R ~ 400-mm > skin-depth) cylindrical metal rod platform in a Z-pinch configuration was fielded on the Sandia 100-ns, 900-kA Mykonos LTD. PDV expansion velocity measurements of the aluminum rod surface benchmarked equation of state (EOS) and electrical conductivity models used in MHD simulations. The metal surface in simulation expanded along the liquid-vapor coexistence curve for all EOS models. These expansion velocities were compared against the PDV data to validate the EOS used. Several tabular electrical conductivity models were also compared. The models predicted varying surface velocities due to differing Ohmic heating rates. Once the surface vaporized, the expansion behaviors varied widely by table with some simulations showing thermal plasma formation in 1D simulations and others not.