TY - JOUR

T1 - A Resonance Broadening Kinetic Theory of the Modified-two-stream Instability

T2 - Implications for Radar Auroral Backscatter Experiments

AU - Robinson, T. R.

AU - Honary, F.

N1 - An edited version of this paper was published by AGU. Copyright 1990 American Geophysical Union. Robinson, T. R., and F. Honary (1990), A resonance broadening kinetic theory of the modified two‐stream instability: Implications for radar auroral backscatter experiments, J. Geophys. Res., 95(A2), 1073–1085, doi: 10.1029/JA095iA02p01073.

PY - 1990/2/1

Y1 - 1990/2/1

N2 - The kinetic theory of the modified two‐stream instability (MTSI) is usually considered more accurate than the corresponding fluid theory, for the purpose of interpreting VHF and UHF coherent radar backscatter measurements. However, recent developments in the nonlinear theory of the MTSI have retained the fluid theory formalism and consequently may not be entirely valid in the short‐wavelength regime where VHF and UHF radars operate. In this paper, a nonlinear kinetic theory dispersion relation which takes account of the nonlinear resonance broadening effects is developed. With the aid of this dispersion relation, the phase speeds of the short wavelength plasma waves are calculated, as functions of wavelength, aspect angle, and flow angle. The results indicate that phase speeds tend to increase with increasing drift speed, at all wavelengths. Furthermore, under given flow conditions, the phase speeds are relatively insensitive to the flow angle and aspect angle but vary consideraby with altitude. However, unlike long‐wavelength fluid type waves, short‐wavelength MTSI waves are moderately dispersive, the shorter wavelengths having the larger phase speeds. Finally, these kinetic theory calculations are also used to estimate the form of the k spectrum of saturated MTSI waves, and the results are compared with previously published fluid theory predictions of spectral density.

AB - The kinetic theory of the modified two‐stream instability (MTSI) is usually considered more accurate than the corresponding fluid theory, for the purpose of interpreting VHF and UHF coherent radar backscatter measurements. However, recent developments in the nonlinear theory of the MTSI have retained the fluid theory formalism and consequently may not be entirely valid in the short‐wavelength regime where VHF and UHF radars operate. In this paper, a nonlinear kinetic theory dispersion relation which takes account of the nonlinear resonance broadening effects is developed. With the aid of this dispersion relation, the phase speeds of the short wavelength plasma waves are calculated, as functions of wavelength, aspect angle, and flow angle. The results indicate that phase speeds tend to increase with increasing drift speed, at all wavelengths. Furthermore, under given flow conditions, the phase speeds are relatively insensitive to the flow angle and aspect angle but vary consideraby with altitude. However, unlike long‐wavelength fluid type waves, short‐wavelength MTSI waves are moderately dispersive, the shorter wavelengths having the larger phase speeds. Finally, these kinetic theory calculations are also used to estimate the form of the k spectrum of saturated MTSI waves, and the results are compared with previously published fluid theory predictions of spectral density.

KW - heating DCS-publications-id

KW - art-80

KW - DCS-publications-personnel-id

KW - 5

U2 - 10.1029/JA095iA02p01073

DO - 10.1029/JA095iA02p01073

M3 - Journal article

VL - 95

SP - 1073

EP - 1085

JO - Journal of Geophysical Research

JF - Journal of Geophysical Research

SN - 0148-0227

IS - A2

ER -