On the dependence of the phase velocity of equatorial irregularities on the polarization electric field and theoretical implications

Journal Article · Mon Dec 01 04:00:00 EST 1986 · J. Geophys. Res.; (United States)

DOI:https://doi.org/10.1029/JA091iA12p13493· OSTI ID:6824274

-Maurice, J; Hanuise, C; Kudeki, E

We have studied the mean Doppler shift of equatorial irregularities in the E region, using data from a coherent radar situated in Ethiopia between 1976 and 1980. We found that even though the primary two-stream (or type I) waves are drifting at a speed close to the expected ion acoustic speed, there is a small but nonnegligible increase in the phase velocity with increasing electron drift in the electrojet. We attribute this increase to a heating of the electron gas by the large-amplitude, low-frequency waves that are present in the region when conditions are favorable to the production of large-scale gradient drift instabilities. On the other hand, for the single day when the production of large-scale gradient drift instabilities was inhibited, the behavior of the irregularities was quite different. Namely, the Doppler shift of 10-m waves (type O waves) was usually below the linear threshold value while the spectra remained narrow and type I-like rather than type II-like. On the other hand, the Doppler shift followed a dependence similar to that expected from type II waves. We have tentatively attributed this type O behavior to weak mode coupling, following similar inferences from recent Condor observations made near the top of the electrojet.

• Research Organization: Max-Planck-Institut fuer Aeronomie, Katlenburg-Lindau, Federal Republic of Germany
• OSTI ID: 6824274
• Journal Information: J. Geophys. Res.; (United States), Journal Name: J. Geophys. Res.; (United States) Vol. 91:A12; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

640201* -- Atmospheric Physics-- Auroral
Ionospheric
& Magetospheric Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
CURRENTS
DOPPLER EFFECT
DRIFT INSTABILITY
E REGION
EARTH ATMOSPHERE
ELECTRIC CURRENTS
ELECTRIC FIELDS
ELECTROJETS
ELECTRON DRIFT
ELECTRON TEMPERATURE
INSTABILITY
IONOSPHERE
MEASURING INSTRUMENTS
PHASE VELOCITY
PLANETARY IONOSPHERES
PLASMA INSTABILITY
PLASMA MICROINSTABILITIES
POLARIZATION
RADAR
RANGE FINDERS
VARIATIONS
VELOCITY