Equation of matter state in the average-ion model for a laser-produced plasma

A thermodynamically consistent model for calculating the equation of plasma state in the average-ion approximation is proposed. The model takes into account the chemical bonds in a solid, the pressure of electron shells of an ion, which arises upon the ion compression, and also the degeneracy of the electron gas at high densities and low temperatures. The calculations of shock compression of different materials, such as liquid deuterium, Al, Be, Fe and Au, carried out using this model showed that it provides a satisfactory description both of the existing experimental results and of the results of calculations involving the Thomas — Fermi model over a broad range of pressure behind the shock front. The isotherms of the above materials calculated in the average-ion approximation and using the Thomas — Fermi model are compared for different temperatures.