The role of the equatorial electrojet in the evening ionosphere

Haerendel, G.; Eccles, J. V.

doi:10.1029/91ja02227

Cited by 133 publications

(148 citation statements)

References 24 publications

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“…Two possible explanations of the relationship between the PRE strength and the pre-sunset IEEJ are suggested. One is a current connection between the daytime EEJ and the vertical current in the F-region around sunset proposed by Haerendel and Eccles (1992). The other is a connection through the modification of plasma density distribution in the equatorial F-region around sunset (Prakash et al, 2009) by the zonal electric field generated in the pre-sunset E-region dynamo.…”

Section: Discussionmentioning

confidence: 99%

“…The other is a connection through the modification of plasma density distribution in the equatorial F-region around sunset (Prakash et al, 2009) by the zonal electric field generated in the pre-sunset E-region dynamo. Haerendel and Eccles (1992) suggest that EEJ is required to flow into a low conductivity region around sunset for establishing the current connection between the daytime EEJ and the vertical current generated by the F-region dynamo around sunset. Subsequently, an additional eastward electric field that strengthens PRE can originate.…”

Section: Discussionmentioning

confidence: 99%

“…Then, the relationships should be examined in more detail whether they are valid in any season and longitude. On the other hand, Haerendel and Eccles (1992) found, by performing calculations, that the dayside EEJ flows into the night side region and that the vertical divergent current of EEJ connects to the vertical Fregion dynamo current. The existence of the divergent current of EEJ has been observationally verified by Denardini et al (2006).…”

Section: Introductionmentioning

confidence: 99%

“…A mechanism of PRE has been investigated with numerical techniques, and the Fregion dynamo has been considered as the primary origin of PRE (e.g., Eccels, 1998;Heelis, 2004). However, detailed physical processes connecting the F-region dynamo and PRE appear to be complicated, and several explanations have been proposed (e.g., Rishbeth, 1971;Farley et al, 1986;Haerendel and Eccles, 1992;Eccles, 1998). Haerendel and Eccles (1992) investigated a current system around sunset by inputting arbitrary zonal electric field variations in their model.…”

Section: Introductionmentioning

confidence: 99%

“…However, detailed physical processes connecting the F-region dynamo and PRE appear to be complicated, and several explanations have been proposed (e.g., Rishbeth, 1971;Farley et al, 1986;Haerendel and Eccles, 1992;Eccles, 1998). Haerendel and Eccles (1992) investigated a current system around sunset by inputting arbitrary zonal electric field variations in their model. They found that the dayside EEJ flows into a night side region and that a vertical divergent current of EEJ connects to the vertical F-region dynamo current.…”

Section: Introductionmentioning

confidence: 99%

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Relationships between pre-sunset electrojet strength, pre-reversal enhancement and equatorial spread-F onset

et al. 2010

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Abstract. The virtual height of the bottom side F-region (h F ) and equatorial spread-F (ESF) onsets at Chumphon (10.7 • N, 99.4 • E; 3.3 • N magnetic latitude) were compared with the behaviour of equatorial electrojet (EEJ) ground strength at Phuket (8.1 • N, 98.3 • E; 0.1 • N magnetic latitude) during the period from November 2007 to October 2008. Increase in the F-layer height and ESF onsets during the evening hours were well connected with the EEJ ground strength before sunset, namely, both the height increase and ESF onsets were suppressed when the integrated EEJ ground strength for the period from 1 to 2 h prior to sunset was negative. The finding suggests observationally that the pre-sunset E-region dynamo current and/or electric field are related to the F-region dynamics and ESF onsets around sunset.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Relationships between pre-sunset electrojet strength, pre-reversal enhancement and equatorial spread-F onset

et al. 2010

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A study on ionospheric scintillation near the EIA crest in relation to equatorial electrodynamics

Chatterjee¹,

Chakraborty²,

Veenadhari³

et al. 2014

JGR Space Physics

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Equatorial electrojet (EEJ) data, which are considered as a proxy index of equatorial electric field, are analyzed in conjunction with equatorial ionosonde, total electron content (TEC) and scintillation data near the equatorial ionization anomaly (EIA) crest for the equinoctial months of high solar activity years (2011)(2012) to identify any precursor index of postsunset evolution of equatorial electron density irregularities and subsequent occurrence of scintillation near the northern EIA crest. Only geomagnetically quiet and normal electrojet days are considered. The diurnal profiles of EEJ on the scintillation days exhibit a secondary enhancement in the afternoon to presunset hours following diurnal peaks. A series of electrodynamical processes conducive for generation of irregularities emerge following secondary enhancement of EEJ. Latitudinal profile of TEC exhibits resurgence in EIA structure around the postsunset period. Diurnal TEC profile near the EIA crest resembles postsunset secondary enhancement on the days with afternoon enhancement in EEJ. Occurrence of equatorial spread F and postsunset scintillation near the EIA crest seems to follow the secondary enhancement events in EEJ. Both the magnitude and duration of enhanced EEJ are found to be important for postsunset intensification of EIA structure and subsequent occurrence of equatorial irregularities. A critical value combining the two may be considered an important precursor for postsunset occurrence of scintillation near the EIA crest. The results are validated using archived data for the years 1989-1990 and explained in terms of modulation effects of enhanced equatorial fountain.

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Data‐driven numerical simulations of equatorial spread F in the Peruvian sector

et al. 2014

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Ionospheric state parameters including plasma number density and vector drift velocity profiles were measured at the Jicamarca Radio Observatory during a campaign running from 12 to 18 April 2013. Neutral winds were measured by the red-line Fabry Perot interferometer at Jicamarca. Coherent radar backscatter from plasma irregularities associated with equatorial spread F (ESF) was also recorded. A numerical simulation of ionospheric irregularities, initialized and forced using parameterizations derived from a combination of measurements and empirical models, was used to try to reproduce the ESF activity that occurred on three different nights. Simulations were able to recover the salient features of the irregularities that formed in each case and produce bottom-type, bottomside, and topside ESF. Realistic simulations require the accurate representation of the vertical currents that generate irregularities initially at the base of the F region as well as the zonal currents necessary for irregularities to expand in altitude and penetrate to the topside. The campaign data, numerical simulations, and protocols used to associate them are presented and evaluated.

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The role of the equatorial electrojet in the evening ionosphere

Cited by 133 publications

References 24 publications

Relationships between pre-sunset electrojet strength, pre-reversal enhancement and equatorial spread-F onset

Relationships between pre-sunset electrojet strength, pre-reversal enhancement and equatorial spread-F onset

A study on ionospheric scintillation near the EIA crest in relation to equatorial electrodynamics

Data‐driven numerical simulations of equatorial spread F in the Peruvian sector

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