Radial Distribution Functions of Strongly Coupled Two-Temperature Plasmas

We present tests of three theoretical models for the radial distribution functions (RDFs) in two-temperature strongly coupled plasmas. RDFs are useful in extending plasma thermodynamics and kinetic theory to strong coupling, but they are usually known only for thermal equilibrium or for approximate one-component model plasmas. Accurate two-component modeling is necessary to understand the impact of strong coupling on inter-species transport, e.g., ambipolar diffusion and electron-ion temperature relaxation. We demonstrate that the Seuferling-Vogel-Toeppfer (SVT) extension\footnote{P.~Seuferling, J.~Vogel, and C.~Toepffer, Phys.~Rev.~A \textbf{40} (1989).} of the hypernetted chain equations not only gives accurate RDFs (as compared with classical molecular dynamics simulations), but also has a simple connection with the Yukawa OCP model. This connection gives a practical means to recover the structure of the electron background from knowledge of the ion-ion RDF alone. Using the model RDFs in Effective Potential Theory\footnote{S.~D.~Baalrud and J.~Daligault, Phys.~Rev.~Lett.~\textbf{100} (2013)}, we report the first predictions of inter-species transport coefficients of strongly coupled plasmas far from equilibrium.