Coupling effect of the equatorial F region irregularities on the low latitude E region instability processes

Patra, Amit; Sripathi, S.; Tiwari, Diwakar

doi:10.1029/2004gl020486

Cited by 20 publications

(37 citation statements)

References 17 publications

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“…10a and b show the occurrence of E region echoes corresponding to ESF plume events and without overhead ESF, respectively, based on Gadanki radar observations. These results are quite similar to those reported by Patra et al (2004b) except the fact that the results shown in Fig. 10a are generated with clear cases of radar plumes observed in the early part of nights in the Gadanki radar observations.…”

Section: E Region Aspectssupporting

confidence: 91%

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Some aspects of electrostatic coupling between E and F regions relevant to plasma irregularities: A review based on recent observations

Patra¹

2008

Journal of Atmospheric and Solar-Terrestrial Physics

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Section: E Region Aspectssupporting

confidence: 91%

“…Based on Gadanki radar observations, Patra et al (2004b) evaluated the disruption of E region echoes in connection with ESF plumes reported earlier by Hysell et al (1994) and Rao et al (1997). They showed that the E region echoes are disrupted when the high altitude plumes with upward drifts are observed.…”

Section: E Region Aspectsmentioning

confidence: 99%

Some aspects of electrostatic coupling between E and F regions relevant to plasma irregularities: A review based on recent observations

Patra¹

2008

Journal of Atmospheric and Solar-Terrestrial Physics

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“…Kelley et al (2002) and Ostuka et al (2002) have detected the effects of equatorial bubble at far off-equatorial latitude stations. The low-latitude observations from Indian MST and EAR radars (Patra et al, 2004;Yokoyama et al, 2005) reveal the presence of valley region echoes and suppression of E region irregularities. These phenomena are again linked to the polarization field of equatorial bubble (Patra et al, 2005).…”

Section: Introductionmentioning

confidence: 93%

A Three-Dimensional Simulation of Collisional-Interchange-Instability in the Equatorial-Low-Latitude Ionosphere

Kherani¹,

Mascarenhas

Paula

et al. 2005

Space Sci Rev

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We present a three-dimensional simulation of collisional-interchange-instability in the equatorial-low-latitude F region of ionosphere. The instability is responsible for the generation of large plasma density depletion or bubble. General 3D potential and continuity equations are derived to simulate the phenomena. To understand the linear aspect of the instability, the general 3D linear growth rate is derived using 3D potential equation. The linear growth characteristics are compared with earlier field-aligned-integrated growth analyses. The numerical simulation of bubble in the 3D spherical polar geometry is finally presented. Distinct evolution characteristics of bubble in 3D and 2D simulation are further discussed.

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“…In the NS plane they can point perpendicular to the magnetic field at both E-and Fregion altitudes and obtain echoes from both regions simultaneously. By doing so they find that whenever Spread F bubbles appear, the E-region echoes weaken or disappear (Patra et al, 2004), as seen in Fig. 16.…”

Section: Satellites Rockets and Other Radars And Radar Techniquesmentioning

confidence: 81%

Spread F – an old equatorial aeronomy problem finally resolved?

2009

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Abstract. One of the oldest scientific topics in EquatorialAeronomy is related to Spread-F. It includes all our efforts to understand the physical mechanisms responsible for the existence of ionospheric F-region irregularities, the spread of the traces in a night-time equatorial ionogram -hence its name -and all other manifestations of the same. It was observed for the first time as an abnormal ionogram in Huancayo, about 70 years ago. But only recently are we coming to understand the physical mechanisms responsible for its occurrence and its capricious day to day variability. Several additional techniques have been used to reveal the spatial and temporal characteristics of the F-region irregularities responsible for the phenomenon. Among them we have, in chronological order, radio star scintillations, trans-equatorial radio propagation, satellite scintillations, radar backscatter, satellite and rocket in situ measurements, airglow, total electron content techniques using the propagation of satellite radio signals and, recently, radar imaging techniques. Theoretical efforts are as old as the observations. Nevertheless, 32 years after their discovery, Jicamarca radar observations showed that none of the theories that had been put forward could explain them completely. The observations showed that irregularities were detected at altitudes that were stable according to the mechanisms proposed. A breakthrough came a few years later, again from Jicamarca, by showing that some of the "stable" regions had become unstable by the non-linear propagation of the irregularities from the unstable to the stable region of the ionosphere in the form of bubbles of low density plasma. A problem remained, however; the primary instability mechanism proposed, an extended (generalized) Rayleigh-Taylor instability, was too slow to explain the rapid development seen by the observations. Gravity waves in the neutral background have been proposed as a seeding mechaCorrespondence to: R. F. Woodman (ronw@geo.igp.gob.pe) nism to form irregularities from which the instability would grow, but the former are difficult to observe as a controlling parameter. Their actual role still needs to be determined. More recently, radar observations again have shown the existence of horizontal plasma drift velocities counter streaming the neutral wind at the steep bottom of the F-region which produces a fast growing instability from which a generalized Rayleigh-Taylor instability can grow. The mechanisms proposed would explain the rapid development of the large and medium scale irregularities that have been observed, including some seen only by radars. Nevertheless, a proper quantitative theoretical mechanism that would explain how these irregularities break into the very important meter scale ones, responsible for the radar echoes, needs to be developed. This paper makes a selective historical review of the observations and proposed theories since the phenomenon was discovered to our current understanding.

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Coupling effect of the equatorial F region irregularities on the low latitude E region instability processes

Cited by 20 publications

References 17 publications

Some aspects of electrostatic coupling between E and F regions relevant to plasma irregularities: A review based on recent observations

Some aspects of electrostatic coupling between E and F regions relevant to plasma irregularities: A review based on recent observations

A Three-Dimensional Simulation of Collisional-Interchange-Instability in the Equatorial-Low-Latitude Ionosphere

Spread F – an old equatorial aeronomy problem finally resolved?

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