Equation of state of classical Coulomb plasma mixtures

TL;DR

This paper presents analytic approximations for the thermodynamic properties of nonideal Coulomb plasma mixtures, bridging strong and weak coupling regimes with improved accuracy through hypernetted-chain calculations and corrections to the linear mixing rule.

Contribution

It introduces a new analytic framework for plasma mixtures that accurately models thermodynamic functions across coupling regimes, improving upon previous models.

Findings

Accurate analytic approximations for plasma thermodynamics across coupling regimes.

Successful transition modeling from strong to weak Coulomb coupling.

Validation against hypernetted-chain numerical calculations.

Abstract

We develop analytic approximations of thermodynamic functions of fully ionized nonideal electron-ion plasma mixtures. In the regime of strong Coulomb coupling, we use our previously developed analytic approximations for the free energy of one-component plasmas with rigid and polarizable electron background and apply the linear mixing rule (LMR). Other thermodynamic functions are obtained through analytic derivation of this free energy. In order to obtain an analytic approximation for the intermediate coupling and transition to the Debye-Hueckel limit, we perform hypernetted-chain calculations of the free energy, internal energy, and pressure for mixtures of different ion species and introduce a correction to the LMR, which allows a smooth transition from strong to weak Coulomb coupling in agreement with the numerical results.