Accession Number : AD0775596

Title :   Parallel Propagation Effects on the Type I Electrojet Instability.

Descriptive Note : Interim rept.,

Corporate Author : NAVAL RESEARCH LAB WASHINGTON D C

Personal Author(s) : Ossakow,Sidney L. ; Papadopoulos,Konstantinos ; Orens,Joseph H. ; Coffey,Timothy P.

Report Date : MAR 1974

Pagination or Media Count : 28

Abstract : The Farley-Buneman instability has been extended to consider higher frequency, shorter wavelength modes (thus including finite Debye length effects) while allowing these modes to propagate with a component parallel to the magnetic field (k parallel not = 0). By driving the current sufficiently hard (drift speeds in the range 2-3 times the ion thermal velocity, vi) the growth rates of these modes maximize slightly away from the perpendicular to the magnetic field showing the importance of k parallel not = 0. Although the wavelengths of these maximum growing modes are in the regime of several to tens of centimeters, the phase velocities are near the ion thermal velocity. This suggests that a nonlinear coupling of these off angle modes may be responsible for the observed radar spectrum with maximum intensity near vi and wavelengths in the 1-10 meter regime. Maximum growth rates of off angle propagation while varying the densities and collision frequencies are shown. Also, growth rates of unstable waves in the radar regime (1-10 meters) are shown for drift velocities 1.5 and 3 times vi. (Modified author abstract)

Descriptors :   *Ionospheric disturbances, Electron density, Electric current, Equatorial regions, Radar reflections, Backscattering

Subject Categories : Atmospheric Physics

Distribution Statement : APPROVED FOR PUBLIC RELEASE