Title: Hydrodynamic limit of Wigner-Poisson kinetic theory: Revisited

In this paper, we revisit the hydrodynamic limit of the Langmuir wave dispersion relation based on the Wigner-Poisson model in connection with that obtained directly from the original Lindhard dielectric function based on the random-phase-approximation. It is observed that the (fourth-order) expansion of the exact Lindhard dielectric constant correctly reduces to the hydrodynamic dispersion relation with an additional term of fourth-order, beside that caused by the quantum diffraction effect. It is also revealed that the generalized Lindhard dielectric theory accounts for the recently discovered Shukla-Eliasson attractive potential (SEAP). However, the expansion of the exact Lindhard static dielectric function leads to a k{sup 4} term of different magnitude than that obtained from the linearized quantum hydrodynamics model. It is shown that a correction factor of 1/9 should be included in the term arising from the quantum Bohm potential of the momentum balance equation in fluid model in order for a correct plasma dielectric response treatment. Finally, it is observed that the long-range oscillatory screening potential (Friedel oscillations) of type cos(2k{sub F}r)/r{sup 3}, which is a consequence of the divergence of the dielectric function at point kâ=â2k{sub F} in a quantum plasma, arises due to the finiteness of the Fermi-wavenumber and ismore » smeared out in the limit of very high electron number-densities, typical of white dwarfs and neutron stars. In the very low electron number-density regime, typical of semiconductors and metals, where the Friedel oscillation wavelength becomes much larger compared to the interparticle distances, the SEAP appears with a much deeper potential valley. It is remarked that the fourth-order approximate Lindhard dielectric constant approaches that of the linearized quantum hydrodynamic in the limit if very high electron number-density. By evaluation of the imaginary part of the Lindhard dielectric function, it is shown that the Landau-damping region in Ï-k plane increases dramatically by increase of the electron number-density.« less

Faculty of Sciences, Department of Physics, Azarbaijan Shahid Madani University, 51745-406 Tabriz (Iran, Islamic Republic of)

(Germany)

Publication Date:

OSTI Identifier:

22408056

Resource Type:

Journal Article

Resource Relation:

Journal Name: Physics of Plasmas; Journal Volume: 22; Journal Issue: 2; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)

Country of Publication:

United States

Language:

English

Subject:

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; BOHM CRITERION; DIELECTRIC MATERIALS; DIFFRACTION; DISPERSION RELATIONS; ELECTRON DENSITY; FLOW MODELS; HYDRODYNAMICS; LANDAU DAMPING; METALS; NEUTRON STARS; OSCILLATIONS; PERMITTIVITY; QUANTUM PLASMA; RANDOM PHASE APPROXIMATION; SEMICONDUCTOR MATERIALS; WAVELENGTHS; WHITE DWARF STARS