Dielectric function of a collisional plasma for arbitrary ionic charge

Abstract

A simple model for the dielectric function of a completely ionized plasma with an arbitrary ionic charge, that is valid for long-wavelength high-frequency perturbations is derived using an approximate solution of a linearized Fokker-Planck kinetic equation for electrons with a Landau collision integral. The model accounts for both the electron-ion collisions and the collisions of the subthermal (cold) electrons with thermal ones. The relative contribution of the latter collisions to the dielectric function is treated phenomenologically, introducing some parameter κ that is chosen in such a way as to get a well-known expression for stationary electric conductivity in the low-frequency region and fulfill the requirement of a vanishing contribution of electron-electron collisions in the high-frequency region. This procedure ensures the applicability of our model in a wide range of plasma parameters as well as the frequency of the electromagnetic radiation. Unlike the interpolation formula proposed earlier by Brantov et al. [Brantov et al., JETP 106, 983 (2008)

Dielectric function of dense plasmas, their stopping power, and sum rules

“…A recent model by Nersisyan et al [84] from the point of view of the sum-rule approach does not go beyond the Drude-Lorentz model, i.e., it accounts for the zeroth sum rule only [see (6) and Sec. II A].…”

“…[83(b)]. The latter model of [84] contains two adjustment parameters and it is curious that in that work the interpolation with the static conductivity is also involved, like we do when we construct the Nevanlinna parameter function of the method of moments on the basis of an interpolation between the Perel'-Eliashberg asymptotic form of the two-component plasma dielectric function and its static conductivity. Finally, the data on the molecular-dynamics simulations of the classical stopping power [85] is interesting from a methodological point of view, but the thermodynamic conditions modeled in this work actually do not correspond to those of classical plasmas.…”

Optical conductivity of warm dense matter within a wide frequency range using quantum statistical and kinetic approaches

“…A slightly more complex, but still elementary approach is based on an approximate solution of the Fokker-Planck equation as proposed in Ref. [65]. This permits to take into account not only the contribution of electron-ion collisions to the DF ε(ω) (as in the case of relaxation time approximation), but also of electron-electron collisions.…”

“…This permits to take into account not only the contribution of electron-ion collisions to the DF ε(ω) (as in the case of relaxation time approximation), but also of electron-electron collisions. In accordance with [65], the permittivity of plasmas due to intra-band transitions is expressed as…”

“…The function κ is constructed in such a way [65] that limits at high and low laser frequencies and for nondegenerate [66] as well as for degenerate [33] matter are fulfilled:…”