Equation of state using scaled binding energy model

Abstract

Global equation of state models are currently used for hydrodynamic simulations of inertial confinement fusion systems. The quotidian equation of state (QEOS) is one of such models. In spite of a sound theoretical basis, QEOS uses two empirical corrections for obtaining agreement with measured shock wave data. While the first is used for all materials, the second is to account for structural phase transitions. Evaluation of these corrections requires a priori knowledge of experimental data. Two improvements to QEOS proposed in this article obviate the use of both corrections. First, a modified version of the universal scaled binding energy is used for the zero-temperature isotherm. Then, an expression is derived for the Grüneisen parameter γ(ρ), which also includes the noncentral features of interparticle potential. The Debye temperature and melting temperature, deduced from γ(ρ), show excellent agreement with experimental results or electronic structure calculations. Predictions of the improved EOS model also compare very well with measured Hugoniot for normal metals such as Al, Cu, Pd, Pt, etc., and Fe and Zr, which undergo shock induced phase transitions.