Landau damping in space plasmas
Abstract
Space plasmas typically possess a particle distribution function with an enhanced highenergy tail that is well modeled by a generalized Lorentzian (or kappa) distribution with spectral index {kappa}. The modified plasma dispersion function {bold Z}{sup *}{sub {kappa}}({xi}) is employed to analyze the Landau damping of (electrostatic) Langmuir waves and ionacoustic waves in a hot, isotropic, unmagnetized, generalized Lorentzian plasma, and the solutions are compared with the classical results for a Maxwellian plasma. Numerical solutions for the real and imaginary parts of the wave frequency {omega}{sub 0}{minus}{ital i}{gamma} are obtained as a function of the normalized wave number {ital k}{lambda}{sub D}, where {lambda}{sub D} is the electron Debye length. For both particle distributions the electrostatic modes are strongly damped, {gamma}/{omega}{sub 0}{much gt}1, at short wavelengths, {ital k}{lambda}{sub D}{much gt}1. This collisionless damping becomes less severe at long wavelengths, {ital k}{lambda}{sub D}{much lt}1, but the attenuation of Langmuir waves is much stronger for a generalized Lorentzian plasma than for a Maxwellian plasma. This will further localize Langmuir waves to frequencies just above the electron plasma frequency in plasmas with a substantial highenergy tail. Landau damping of ionacoustic waves is only slightly affected by the presence of a highenergy tail, but is stronglymore »
 Authors:

 Department of Atmospheric Sciences, University of California at Los Angeles, Los Angeles, California 900241565 (USA)
 Department of Mathematics and Statistics, Memorial University of Newfoundland, St. John's, Newfoundland A1C 5S7 Canada (CA)
 Publication Date:
 OSTI Identifier:
 5666166
 Resource Type:
 Journal Article
 Journal Name:
 Physics of Fluids B; (United States)
 Additional Journal Information:
 Journal Volume: 3:8; Journal ID: ISSN 08998221
 Country of Publication:
 United States
 Language:
 English
 Subject:
 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; HOT PLASMA; PLASMA WAVES; DISPERSION RELATIONS; DISTRIBUTION FUNCTIONS; ION ACOUSTIC WAVES; ISOTROPY; LANDAU DAMPING; LORENTZ GAS; MODIFICATIONS; SPACE; DAMPING; FLUIDS; FULLY IONIZED GASES; FUNCTIONS; GASES; ION WAVES; IONIZED GASES; PLASMA; 640201*  Atmospheric Physics Auroral, Ionospheric, & Magetospheric Phenomena
Citation Formats
Thorne, R M, and Summers, D. Landau damping in space plasmas. United States: N. p., 1991.
Web. doi:10.1063/1.859624.
Thorne, R M, & Summers, D. Landau damping in space plasmas. United States. doi:10.1063/1.859624.
Thorne, R M, and Summers, D. Thu .
"Landau damping in space plasmas". United States. doi:10.1063/1.859624.
@article{osti_5666166,
title = {Landau damping in space plasmas},
author = {Thorne, R M and Summers, D},
abstractNote = {Space plasmas typically possess a particle distribution function with an enhanced highenergy tail that is well modeled by a generalized Lorentzian (or kappa) distribution with spectral index {kappa}. The modified plasma dispersion function {bold Z}{sup *}{sub {kappa}}({xi}) is employed to analyze the Landau damping of (electrostatic) Langmuir waves and ionacoustic waves in a hot, isotropic, unmagnetized, generalized Lorentzian plasma, and the solutions are compared with the classical results for a Maxwellian plasma. Numerical solutions for the real and imaginary parts of the wave frequency {omega}{sub 0}{minus}{ital i}{gamma} are obtained as a function of the normalized wave number {ital k}{lambda}{sub D}, where {lambda}{sub D} is the electron Debye length. For both particle distributions the electrostatic modes are strongly damped, {gamma}/{omega}{sub 0}{much gt}1, at short wavelengths, {ital k}{lambda}{sub D}{much gt}1. This collisionless damping becomes less severe at long wavelengths, {ital k}{lambda}{sub D}{much lt}1, but the attenuation of Langmuir waves is much stronger for a generalized Lorentzian plasma than for a Maxwellian plasma. This will further localize Langmuir waves to frequencies just above the electron plasma frequency in plasmas with a substantial highenergy tail. Landau damping of ionacoustic waves is only slightly affected by the presence of a highenergy tail, but is strongly dependent on the ion temperature. Owing to the simple analytical form of the modified plasma dispersion function when {kappa}=2 (corresponding to a pronounced highenergy tail), exact analytical results for the real and imaginary parts of the wave frequency can be found in this case; similar solutions are not available for a Maxwellian plasma.},
doi = {10.1063/1.859624},
journal = {Physics of Fluids B; (United States)},
issn = {08998221},
number = ,
volume = 3:8,
place = {United States},
year = {1991},
month = {8}
}