Equatorial ionosphere responses to two magnetic storms of moderate intensity from conjugate point observations in Brazil

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dc.contributor.authorAbdu M.A.
dc.contributor.authorBatista I.S.
dc.contributor.authorBertoni F.
dc.contributor.authorReinisch B.W.
dc.contributor.authorKherani E.A.
dc.contributor.authorSobral J.H.A.
dc.date.accessioned2024-03-13T01:09:13Z
dc.date.available2024-03-13T01:09:13Z
dc.date.issued2012
dc.description.abstractEquatorial ionospheric responses during two magnetic storms of moderate intensity are investigated, for the first time, by conjugate point observations in Brazil. The study focuses on storm-induced changes in the evening prereversal vertical drift, thermospheric trans-equatorial winds, spread F/plasma bubble irregularity development, electron density/plasma frequency heights, the EIA strength, and zonal plasma drifts. It is based on data obtained from five Digisondes operated in Brazil, three of them being part of a conjugate point equatorial experiment (COPEX) involving a dip equatorial and two magnetic conjugate sites at ±12°. The other two were operated at the equatorial ionization anomaly (EIA) trough and crest locations at nearby magnetic meridians. The results bring out, and clarify, many outstanding aspects of the strong influence of storm time electric fields on the equatorial ionosphere at different phases of the two long lasting storm sequences. During both storms prompt penetration electric fields dominated the ionospheric response features as compared to the disturbance wind dynamo effects that were not very conspicuous. An under-shielding (over-shielding) electric field occurring in the evening hours causes enhancement (suppression) of the prereversal vertical drift and post sunset spread F/plasma bubble generation. The same electric fields cause post sunset EIA enhancement and suppression, respectively. Post sunset (post midnight) spread F can develop from under-shielding (over-shielding) electric fields, while it can be disrupted by over-shielding (under-shielding) electric field. Trans-equatorial winds are found to be ineffective to stabilize the post sunset F region against the destabilizing effect of strong prereversal vertical drift. Storm time westward plasma drifts are found to be driven by prompt penetration eastward electric fields (through their effect of inducing vertical Hall electric fields), rather than by a disturbance westward thermospheric wind during these storms.
dc.description.issuenumber5
dc.description.volume117
dc.identifier.doi10.1029/2011JA017174
dc.identifier.issn2169-9402
dc.identifier.urihttps://dspace.mackenzie.br/handle/10899/36873
dc.relation.ispartofJournal of Geophysical Research: Space Physics
dc.rightsAcesso Aberto
dc.titleEquatorial ionosphere responses to two magnetic storms of moderate intensity from conjugate point observations in Brazil
dc.typeArtigo
local.scopus.citations28
local.scopus.eid2-s2.0-84861438326
local.scopus.updated2024-05-01
local.scopus.urlhttps://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84861438326&origin=inward
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