Diffusive Mixing in Strongly Coupled Plasmas

A multispecies hydrodynamic model based on moments of the Born-Bogolyubov-Green-Kirkwood-Yvon (BBGKY) hierarchy [1] is developed for physical conditions relevant to astrophysical plasmas. The modified transport equations incorporate strong correlations through a density functional theory closure, while fluctuations enters through a mixture BGK operator. This model extends the usual Burgers equations for a dilute gas to strongly coupled and isothermal plasmas mixtures. The diffusive currents for these strongly coupled plasmas is self-consistently derived. The settling of impurities and its impact on cooling of white dwarfs and neutron stars [2] can be greatly affected by strong Coulomb coupling, which we show can be quantified using the direct-correlation function. [1] A. Diaw and M. S. Murillo, Phys. Rev. E, 92, 013107 (2015) [2] A. Diaw and M. S. Murillo (to appear in Astrophysical Journal, 2016).