Statistical mechanics of a two-temperature, classical plasma

Weakly coupled, nonequilibrium plasmas have often been described by assigning separate temperatures to the electron and ion velocity distributions. In this paper we present a model for the complete phase-space probability function which describes a two-temperature ensemble for arbitrary coupling. We discuss the ``thermodynamics'' predicted by the model, and in the limit of weak electron-ion coupling, we obtain explicit expressions for both the static and dynamic structure factors, which remain valid even for strong ion-ion coupling. When the ions become weakly coupled, our results for the static structure factors reduce to those of Salpeter. However, even in this limit there remains a small difference from Salpeter's dynamic structure factor due to the nonergodicity of the ensemble.