On the application of plasma kinetic theory to electron-ion transport in warm dense matter*

Modern astrophysics and laboratory experiments push plasma physics into regimes beyond the limits of its established microscopic theories. This talk concerns extending these limits to encompass plasmas that are subject to moderate Coulomb correlations in addition to electron degeneracy. This parameter regime is called warm dense matter (WDM). Recent high-fidelity ab initio computational models have proven effective in predicting properties of WDM but the computational expense prohibits the exploration of large parameter spaces. Here, we demonstrate a new method for calculating transport in WDM that balances ease of evaluation with physical fidelity. The method generalizes the recently developed mean force kinetic theory [S. D. Baalrud and J. Daligault, Phys. Plasmas 26, 082106 (2019)] to treat the quantum statistics and dynamics of electrons under WDM conditions. The convergent quantum kinetic equation developed and applied here is highly analogous to the quantum Boltzmann equation of Uehling and Uhlenbeck, but with the effect of strong coupling incorporated through the scattering potential, which is the potential of mean force obtained from equilibrium quantum statistical mechanics.  Focusing on ion-electron collisions, we apply the model to predict temperature and momentum relaxation, the e-i contribution to electrical conductivity, and the stopping power of fully ionized ions in warm dense deuterium. We select a density and range of temperatures to span classical and weakly coupled to degenerate and moderately coupled conditions and find that the model shows promising agreement with ab initio simulations. To conclude we discuss the limitations, possible improvements, and additional applications of the theory.