Transequatorial F-region ionospheric plasma bubbles: solar cycle effects

Sahai, Y.; Fagundes, P. R.; Bittencourt, J. A.

doi:10.1016/s1364-6826(00)00179-6

Cited by 124 publications

(123 citation statements)

References 17 publications

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“…All the other nights (20)(21)(22)(23)(24)(25)(25)(26)(26)(27) show the presence of phase fluctuations up to UEPP in the pre-midnight (local-time) sector starting at about 21:00 LT. As mentioned earlier this could be due to disturbance dynamo effect. Sahai et al (2000) using the OI 630 nm all-sky imaging observations of equatorial plasma bubble observations have previously noted the frequent occurrence of ESF during the month of January in both high and low solar activity. Abdu (1997) has pointed out that while the prompt penetration enhances the upward drift and the disturbance dynamo tends to reduce the upward drifts inhibiting the formation of ESF.…”

Section: Resultsmentioning

confidence: 99%

Studies of ionospheric F-region response in the Latin American sector during the geomagnetic storm of 21–22 January 2005

et al. 2011

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Abstract. In the present investigation, we have studied the response of the ionospheric F-region in the Latin American sector during the intense geomagnetic storm of 21-22 January 2005. This geomagnetic storm has been considered "anomalous" (minimum Dst reached −105 nT at 07:00 UT on 22 January) because the main storm phase occurred during the northward excursion of the B z component of interplanetary magnetic fields (IMFs). The monthly mean

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Section: Resultsmentioning

confidence: 99%

Studies of ionospheric F-region response in the Latin American sector during the geomagnetic storm of 21–22 January 2005

et al. 2011

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“…One of the basic requirements for the development of spread-F is the rapid uplifting of the F-layer to very high altitudes by the pre-reversal enhancement of zonal electric field in the post-sunset hours (Farley et al, 1970;Tsunoda and Ecklund, 2007). The evening vertical drift, or the pre-reversal electric field increases with solar flux (Abdu et al, 1983;Fejer et al, 1999), which could lead to greater rate of occurrence of ESF and EPB during the periods of higher solar activity (Sahai et al, 2000;Sobral et al, 2002). Growth rate for Perkins instability (Perkins, 1973), which is used to explain the generation of MSTID (Kelley and Fukao, 1991), is inversely proportional to ion-neutral collision frequency.…”

Section: Discussionmentioning

confidence: 99%

“…Liu (jyliu@jupiter.ss.ncu.edu.tw) bubbles (EPBs) associated with Equatorial Spread-F (ESF) irregularities (Mendillo and Baumgardner, 1982;Sahai et al, 2000;Fagundes et al, 1999;Taylor et al, 1997;Sinha et al, 2001;Kelley et al, 2002;Makela et al, 2004;Mendillo et al, 2005;Rajesh et al, 2007). The irregularities are generated at the magnetic equator when suitable conditions exist at the F-region bottom-side in the post-sunset period, and manifest themselves as dark bands of intensity depletions in the airglow images taken from equatorial and low-latitude stations (Weber et al, 1978;Mendillo et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

Airglow observations over the equatorial ionization anomaly zone in Taiwan

et al. 2011

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Abstract. Airglow imaging at mid-latitude stations often show intensity modulations associated with medium scale travelling ionospheric disturbances (MSTID), while those carried out near the equatorial regions reveal depletions caused by equatorial plasma bubbles (EPB). Two all sky cameras are used to observe plasma depletions in the 630.0 nm emission over the equatorial ionization anomaly (EIA) region, Taiwan (23 • N, 121 • E; 13.5 • N Magnetic) during 1998-2002 and 2006-2007. The results show EPB and MSTID depletions in different solar activity conditions. Several new features of the EPB depletions such as bifurcation, secondary structure on the walls, westward tilt, etc., are discussed in this paper. Evidence of tilted depletions with secondary structures developing on the eastern wall that later evolve to appear as bifurcations, are presented for the first time. Moreover, detail investigations are carried out using International Reference Ionosphere (IRI) model as well as the electron density from Ionosonde and Global Positioning System (GPS) Occultation Experiment (GOX) onboard FORMOSAT-3/COSMIC satellite, to understand the conditions that favor the propagation of MSTID to the latitude of Taiwan.

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“…There have been many studies on the occurrence characteristics of ionospheric density irregularities using groundbased measurements (Rastogi, 1980;Abdu, 2001), satellitebased in situ measurements (Watanabe and Oya, 1986;Huang et al, 2002;Burke et al, 2004), and topside sounders (Maruyama and Matuura, 1984), and many important features of these have been reported including temporal variations (Sahai et al, 2000;Huang et al, 2002), seasonallongitudinal variability (Burke et al, 2004), several-day variation, and day-to-day variation (Basu et al, 1996) though several enigmatic features of them are yet to be revealed (Thampi et al, 2009). However, studies on continuous and global characteristic features of ionospheric plasma irregularities are very scanty due to the fact that the global coverage is difficult to obtain from ground-based observations.…”

Section: Introductionmentioning

confidence: 99%

A comparison of the equatorial spread F derived by the International Reference Ionosphere and the S 4 index observed by FORMOSAT-3/COSMIC during the solar minimum period of 2007–2009

et al. 2012

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The latest version of the International Reference Ionosphere (IRI-2007) model includes an option for spread-F occurrence prediction for the first-time. The IRI-2007 spread-F occurrence is a function of solar 10.7 cm radiation flux, F 10.7 . In this paper, an attempt is made to cross-examine the spread-F occurrence derived by the IRI-2007 and the ionospheric scintillations in terms of the maximum value of the S 4 index (S 4max ) between 150-350-km altitudes, calculated from fluctuations of the signal-to-noise ratio (SNR) intensity in the L1 channel of GPS radio occultation signals using FORMOSAT-3/COSMIC (F3/C) satellites during the low solar activity years [2007][2008][2009]. It is found that S 4max maintains a fairly good consistency with spread-F occurrence simulated by IRI-2007 in the Brazilian region. Thus, the global S 4 index statistics can be considered as a viable source of database to be incorporated into the global IRI spread-F prediction scheme owing to fact that the F3/C satellites can provide an unprecedented global database including the S 4 index.

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Transequatorial F-region ionospheric plasma bubbles: solar cycle effects

Cited by 124 publications

References 17 publications

Studies of ionospheric F-region response in the Latin American sector during the geomagnetic storm of 21–22 January 2005

Studies of ionospheric F-region response in the Latin American sector during the geomagnetic storm of 21–22 January 2005

Airglow observations over the equatorial ionization anomaly zone in Taiwan

A comparison of the equatorial spread F derived by the International Reference Ionosphere and the S 4 index observed by FORMOSAT-3/COSMIC during the solar minimum period of 2007–2009

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