Comparison of electron–ion energy transfer in dense plasmas obtained from numerical simulations and quantum kinetic theory

Abstract

We evaluate various analytical models for the electron–ion energy transfer and compare the results to data from molecular dynamics (MD) simulations. The models tested include energy transfer via strong binary collisions, Landau–Spitzer rates with different choices for the cut-off parameters in the Coulomb logarithm, rates based on Fermi's golden rule (FGR) and theories taking coupled collective modes (CM) into account. In search of a model easy to apply, we first analyze different approximations of the FGR energy transfer rate. Then, we investigate several numerical studies using MD simulations and try to uncover CM effects in the data obtained. Most MD data published so far, except one study by Murillo et al. [23], show no distinct CM effects and, thus, can be interpreted within a FGR or binary collision approach. We show that this finding is related to the parameter regime, in particular the initial temperature difference, considered in these investigations.