Magnetic-field-aligned characteristics of plasma bubbles in the nighttime equatorial ionosphere

Tsunoda, Roland T.

doi:10.1016/0021-9169(80)90057-4

Cited by 126 publications

(55 citation statements)

References 20 publications

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“…In regards to the later, this correspondence had been shown previously using VHF radar and rocket measurements (Kelley et al, 1976;Morse et al, 1977), but only along a single one-dimensional cut as compared to the 2-dimensional cuts provided by ALTAIR. Tsunoda (1980) showed evidence that the depletions were indeed narrow and elongated in the tilted vertical direction as postulated by Woodman and LaHoz (1976). The instrument is able to observe the background conditions when Spread F radar echoes start to appear.…”

Section: Satellites Rockets and Other Radars And Radar Techniquessupporting

confidence: 62%

“…Tsunoda, 1980;Hysell et al, 2005bHysell et al, , 2006a. One of their first contributions was to show that the enhanced back scatter was related to plasma bubbles, either using only radar data (Tsunoda, 1980) or with simultaneous plasma density satellite in situ measurements (Tsunoda et al, 1982) as shown in Fig. 13.…”

Section: Satellites Rockets and Other Radars And Radar Techniquesmentioning

confidence: 99%

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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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Section: Satellites Rockets and Other Radars And Radar Techniquessupporting

confidence: 62%

Section: Satellites Rockets and Other Radars And Radar Techniquesmentioning

confidence: 99%

Spread F – an old equatorial aeronomy problem finally resolved?

2009

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“…The characteristics and morphology of these depletions, that has been obtained mainly with the Jicamarca radar (e.g. Woodman and La Hoz, 1976), and substantiated by the satellite-based instruments and Altair radar observations (McClure et al, 1977;Dyson and Benson, 1978;Muldrew, 1980;Tsunoda, 1980;Tsunoda et al, 1982;Kil and Heelis, 1998;Yeh et al, 2001), are very well documented. Theoretical and observational investigations indiCorrespondence to: R. Pandey (pandey r@yahoo.com) cate that these depletions are generated on the bottomside of the nighttime equatorial F region and rise to higher altitudes due to the non-linear evolution of the generalized RayleighTaylor and E×B plasma instabilities (Kelley, 1989;Fejer et al, 1999).…”

Section: Introductionmentioning

confidence: 73%

Observations in equatorial anomaly region of total electron content enhancements and depletions

Dashora¹,

Pandey²

2005

Ann. Geophys.

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Abstract.A GSV 4004A GPS receiver has been operational near the crest of the equatorial anomaly at Udaipur, India for some time now. The receiver provides the line-of-sight total electron content (TEC), the phase and amplitude scintillation index, σ φ and S 4 , respectively. This paper presents the first results on the nighttime TEC depletions associated with the equatorial spread F in the Indian zone. The TEC depletions are found to be very well correlated with the increased S 4 index. A new feature of low-latitude TEC is also reported, concerning the observation of isolated and localized TEC enhancements in the nighttime low-latitude ionosphere. The TEC enhancements are not correlated with the S 4 index. The TEC enhancements have also been observed along with the TEC depletions. The TEC enhancements have been interpreted as the manifestation of the plasma density enhancements reported by Le et al. (2003).

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“…Plasma density irregularities in the equatorial ionosphere have long been studied since the starting of the research of spread F phenomena using many kinds of techniques such as ionosondes (RASTOGI, 1980a(RASTOGI, , 1980b and radar backscatter techniques (FARLEY et al, 1970;WOODMAN and LAHOZ, 1976;TSUNODA, 1980aTSUNODA, , 1980bTSUNODA, , 1981TSUNODA and WHITE, 1981;TSUNODA et al, 1979 as well as using spacecrafts as rockets (SZUSZCZEWICZ et al, 1980(SZUSZCZEWICZ et al, , 1981RING et al, 1981;NARCISI and SZUSZCZEWICZ, 1981;KELLEY et al, 1982) and satellites (CLARK and RAITT, 1976;MCCLURE et al, 1977;MULDREW, 1980;BENSON, 1981). One of the remarkable outcome of these observations is the discovery of plasma bubbles in the region of the equatorial F region ionosphere.…”

Section: Introductionmentioning

confidence: 99%

Occurrence characteristics of low latitude ionosphere irregularities observed by impedance probe on board the Hinotori satellite.

Watanabe

Oya

1986

J. geomagn. geoelec

106

119

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The statistical analyses of occurrence characteristics of the plasma bubbles and blobs are made by using more than 1000 cases of observation data from the swept frequency impedance probe aboard the Hinotori satellite. The results show that formations of the plasma bubbles have the following characteristics. 1) The spatial distribution of the occurrence of the plasma bubbles is in the equatorial region within occurrence of the plasma bubbles is limited in the nighttime; favorable periods of the plasma bubble formation depend on the type of the plasma bubbles; multiple plasma bubbles (MPB) have tendency to be generated in pre-midnight, while quasi periodic plasma bubbles (QPB) show their maximum occurrence in the post-midnight period. Solitary plasma bubbles (SPB) occur, however, rather independently to the local time in so far as in the night period, 3) the magnetic activity also controls the occurrence of the plasma bubbles; the occurrence of MPB phenomena shifts the peak period to the midnight side with increasing magnetic activity and the occurrence of QPB phenomena which covers the period from midnight to the morning side shows the expansion of their occurrence into late morning period with increasing magnetic activity, 4) correlation of the occurrence of the plasma bubbles to the solar radiation flux represented by F10.7 solar radio flux is evident for MPB and QPB while there is no relation between F10.7 and the occurrence of SPB. Occurrence of the plasma blobs has a complementary nature with that of the plasma bubbles. The occurrence region of the plasma blobs is limited in the edge parts of the plasma bubble occurrence region being limited in the nighttime. The occurrence of the plasma blobs decreases with increasing magnetic activity, while there is a strong anti-correlation of the occurrence of the plasma blobs to the solar radiation (F10.7). The relation of occurrence of the plasma bubbles and blobs to the development of the equatorial anomaly and the asymmetrical distributions of the background electron density suggests the importance of the generalized Rayleigh-Taylor instability including the effects of the electric field and the neutral wind in addition to the gravitational force for the generation of the plasma bubbles and blobs.

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Magnetic-field-aligned characteristics of plasma bubbles in the nighttime equatorial ionosphere

Cited by 126 publications

References 20 publications

Spread F – an old equatorial aeronomy problem finally resolved?

Spread F – an old equatorial aeronomy problem finally resolved?

Observations in equatorial anomaly region of total electron content enhancements and depletions

Occurrence characteristics of low latitude ionosphere irregularities observed by impedance probe on board the Hinotori satellite.

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