HF Doppler Observations of Small Scale Plasma Motions in the Equatorial Electrojet

• Published in: Physica scripta Vol. 34; no. 6B; pp. 847 - 849
• Main Authors: Sastri, J Hanumath, Ramesh, K B, Rao, J V S V, Rao, D R K
• Format: Journal Article
• Language: English
• Published: Stockholm IOP Publishing 01.12.1986; Royal Swedish Academy of Sciences
• Subjects: Earth, ocean, space; Exact sciences and technology; External geophysics; Ionospheric disturbances; Physics of the ionosphere; Sporadic E; Plasma instability; Equatorial ionosphere; Doppler effect; High frequency; Gradient drift instability; Equatorial electrojet; Normal incidence
• ISSN: 1402-4896; 0031-8949; 1402-4896
• DOI: 10.1088/0031-8949/34/6B/024

Recordings of the variation in the phase path of reflections at vertical incidence from blanketing sporadic-E layers over Kodaikanal (dip 3.5 deg N) revealed small-amplitude, quasi-sinusoidal oscillations of 45-180-s periods in the time rate of change of phase path, (P-dot; Doppler frequency). Geomagnetic micropulsation activity at ground level in the Pc4 range (45-150 s) was not evident at Trivandrum (dip 0.6 deg S, located about 200 km south of Kodaikanal) on all the 26 occasions (out of the total 29 events studied) when geomagnetic data simultaneous with the phase-path observations were available. Besides, the short period quasi-periodic fluctuations in P-dot were also consistently seen in the data of equatorial sporadic E reflections. The observed pulsations in P-dot as representative of those in the vertical electron drift associated with the longitudinal electrostatic-drift waves generated in the equatorial electrojet by the gradient-drift plasma-instability mechanism. (Author)