HF radar studies of two-stream instability during an equatorial counter-electrojet

Journal Article · Sat Sep 01 04:00:00 EDT 1979 · J. Geophys. Res.; (United States)

DOI:https://doi.org/10.1029/JA084iA09p05223· OSTI ID:5865639

Crochet, M; Hanuise, C; Broche, P

A very strong daytime counter-electrojet was observed on January 21, 1977, near the magnetic equator in Africa. This phenomenon was investigated for the first time using simultaneous magnetic and radar measurements. As predicted by the linear theory, irregularities associated with the two-stream instability were detected in the absence of the usual turbulence related to the cross-field effect (or type 2 irregularities). In addition, taking advantage of the refraction of the HF radio waves in the E layer, horizontal or quasi-horizontal plasma waves were detected for the first time together with the usual oblique waves. Two kinds of spectra were then distinguished from the radar observations: (1) Spectra associated with oblique waves which do not have the usual behavior of type 2 (their phase velocity is dependent on time and angle of incidence) and (2) type H spectra associated with horizontal of quasi-horizontal waves which have a smaller phase velocity (constant with time and range) and a a larger amplitude the oblique waves. Among different hypotheses we presume that the quasi-linear reduction of the polarization electric field at the bottom of the instability layer explains the constant value of the phase velocity of the horizontal waves. The absence of turbulence (or type 2) would be the source of the difference observed between oblique waves and usual type 1.

• Research Organization: Laboratoire de Sondages Electromagnetiques de l'Environment Terrestre, Universite de Toulon et du Var La Giponne, 83100 Toulon, France
• OSTI ID: 5865639
• Journal Information: J. Geophys. Res.; (United States), Journal Name: J. Geophys. Res.; (United States) Vol. 84:A9; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

640203* -- Atmospheric Physics-- Magnetospheric Phenomena-- (-1987)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
CURRENTS
EARTH ATMOSPHERE
ELECTRIC CURRENTS
ELECTRIC FIELDS
ELECTROJETS
INSTABILITY
IONOSPHERE
MEASURING INSTRUMENTS
PHASE VELOCITY
PLANETARY IONOSPHERES
PLASMA INSTABILITY
PLASMA MICROINSTABILITIES
PLASMA WAVES
POLARIZATION
RADAR
RANGE FINDERS
SPECTRA
TWO-STREAM INSTABILITY
VELOCITY