Ion potential in warm dense matter: Wake effects due to streaming degenerate electrons

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 ≤ rs ≤ 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.

Ion potential in non‐ideal dense quantum plasmas

“…One can consider the negative minimum in the ion potential to be insignificant as long as the characteristic energy E of the considered process in the plasma is E ≫ |Φ min |. It is worth noting that strong attractions between like‐charged particles exists in both the classical and quantum plasmas out of equilibrium, for example, the presence of a flow of mobile particles relative to the more inert species of particles . In the study by Shukla and Eliasson, using quantum hydrodynamics (QHD), the attraction between like‐charged ions in equilibrium plasmas due to the polarization of the surrounding electrons was reported.…”

Quantum characteristics of occurrence scattering time in two-component non-ideal plasmas

“…In addition, the contribution of electron-atom interaction to the equation of state has been obtained in partially ionized hydrogen plasma using the cluster-virial expansion with the Beth-Uhlenbeck approach [36]. Very recently, the excellent work has provided the effective dynamically screened potential of a classical ion in a stationary flowing quantum plasma at finite temperature based on the Mermin dielectric function [37]. Hence, the investigation of the dynamic screening effects on the occurrence scattering time in dense semiclassical plasmas will be treated elsewhere since the dynamically screened potential is known to be more useful to describe the collision dynamics in plasmas.…”

Effect of the dynamical collision frequency on quantum wakefields

“…Electrons streaming relative to ions can appear in plasmas as a result of the impact by electron (ion) beams and electron acceleration by lasers . In our previous works, we have studied the wakefield created by streaming electrons around an (immobile) ion by using the Mermin dynamical quantum dielectric function in relaxation time approximation . We extensively investigated different plasma parameters (densities, temperatures) and streaming velocities.…”