The ion potential in warm dense matter: wake effects due to streaming degenerate electrons

TL;DR

This paper investigates the dynamically screened ion potential in warm dense matter, revealing wake effects caused by streaming degenerate electrons, and analyzes how temperature and collisions influence these effects for plasma transport phenomena.

Contribution

It extends previous models by including finite temperature and collision effects using the Mermin dielectric function, providing more accurate predictions of wake effects in quantum plasmas.

Findings

Wake effects weaken with increasing electron temperature.

Attraction between ions occurs at streaming velocities below the Fermi velocity.

The results enable reliable predictions of wake effects in nonequilibrium quantum plasmas.

Abstract

The effective dynamically screened potential of a classical ion in a stationary flowing quantum plasma at finite temperature is investigated. This is a key quantity for thermodynamics and transport of dense plasmas in the warm dense matter regime. This potential has been studied before within hydrodynamic approaches or based on the zero temperature Lindhard dielectric function. Here we extend the kinetic analysis by including the effects of finite temperature and of collisions based on the Mermin dielectric function. The resulting ion potential exhibits an oscillatory structure with attractive minima (wakes) and, thus, strongly deviates from the static Yukawa potential of equilibrium plasmas. This potential is analyzed in detail for high-density plasmas with values of the Brueckner parameter in the range $0.1 \le r_s \le 1$, for a broad range of plasma temperature and electron streaming velocity. It is shown that wake effects become weaker with increasing temperature of the electrons. Finally, we obtain the minimal electron streaming velocity for which attraction between ions occurs. This velocity turns out to be less than the electron Fermi velocity. Our results allow, for the first time, for reliable predictions of the strength of wake effects in nonequilibrium quantum plasmas with fast streaming electrons showing that these effects are crucial for transport under warm dense matter conditions, in particular for laser-matter interaction, electron-ion temperature equilibration and for stopping power.