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| Titel |
Non-trough foF2 enhancements at near-equatorial dip latitudes |
| VerfasserIn |
E. Sambou, P. M. Vila, A. T. Kobea |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
0992-7689
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| Digitales Dokument |
URL |
| Erschienen |
In: Annales Geophysicae ; 16, no. 6 ; Nr. 16, no. 6, S.711-720 |
| Datensatznummer |
250013316
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| Publikation (Nr.) |
 copernicus.org/angeo-16-711-1998.pdf |
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| Zusammenfassung |
Fine resolution series from three equatorial
ionosondes of the IEEY network in West Africa have revealed small-scale daytime
peak F2 structures, superposed on the slowly varying minimum or
"trough" distribution in the ±5° magnetic latitude zone. We report
this new morphology, concentrating on foF2 enhancements of two types:
near-equatorial crests (which travel either northwards or southwards) and
magnetic field-aligned domes, whose onsets last only tens of minutes. Both types
are observed to start at mid-morning or early afternoon hours. We relate their
occurrence with the available variations of Vz=E × B
upward drift which feeds the equatorial plasma fountain. We suggest the foF2
enhancements to be triggered by brief slow-downs of the Vz velocity near
F2 peak altitude in our West African sector. Their short latitude extent
differentiates them from the larger-scale tropical crest system. Further
analysis of these features should lead to weather-like models of the low
latitude ionosphere variations, where unstable local coupling between processes
seems to be the trigger.
Key words. Ionosphere (Equatorial ionosphere ·
Ionosphere-atmosphere interaction · Plasma temperature and density) |
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