Simple mixed equation-of-state model of nonideal plasma for simulation of underwater wire explosion

Summary form only given. We present a mixed equation-of-state (EOS) model of nonideal plasma, which is given as a simple combination of the Thomas-Fermi-Dirac (TFD) theory, related ionization fitting formulae and ideal-gas EOS. The mixed EOS model is applied in one-dimensional simulations of under-water wire explosion for comprehensive predictions of the dynamic behaviors and property changes of a single metal wire that is electrically discharged in the water. The TFD part of the EOS model takes account of exchange interactions to give the zero-temperature pressure and energy of electrons at very high densities. The final EOS data at finite temperatures are obtained by adding the temperature-dependent ideal-gas EOS of ions and electrons to the zero-temperature values from the TFD part. Considering its simplicity, this EOS model is in reasonably good agreement with more sophisticated models and/or first-principles calculations as well as it guarantees smooth couplings with hydrodynamic codes. The results of wire explosion simulations are compared with experimental measurements to show the validity of the EOS model. Future applications of the mixed EOS model include modeling and simulations of Z-pinch experiments on a new pulsed-power driver named PRIMA (Pulsed Power Generator for Rapidly Increasing Mega-Ampere Current) which is being designed at ADD.