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| Titel |
A study of evolution/suppression parameters of equatorial postsunset plasma instability |
| VerfasserIn |
O. S. Oyekola |
| 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 ; 27, no. 1 ; Nr. 27, no. 1 (2009-01-16), S.297-301 |
| Datensatznummer |
250016370
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| Publikation (Nr.) |
 copernicus.org/angeo-27-297-2009.pdf |
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| Zusammenfassung |
| Evening equatorial pre-reversal vertical ion E×B
drift (VZP) and the peak of the ionospheric F2 maximum altitude
(hmF2P) of the postsunset equatorial F-layer, which are the essential
parameters requisite for the generation or inhibition of postsunset
bottomside equatorial irregularities were deduced from ionosonde
observations made in the Africa region (Ouagadougou: ~3° N dip
latitude) between January 1987 and December 1990 for solar activity minimum,
medium, and maxima (F10.7=85, 141, 214, and 190, respectively) for
quiet geomagnetic conditions. We investigate variations of evening
equatorial pre-reversal drift and the corresponding altitude at four levels
of solar activity. Our observations show strong variations with solar
variability. Correlation analysis between these parameters indicates that
the correlation coefficient value between hmF2P versus VZP decreases
considerably with increasing solar flux value. There seems to be no
significant link between these parameters under high solar activity,
especially for solar intensity F10.7>200 units. We conclude that
meridional neutral wind in the F-region contributes substantially to the
variations of the pre-reversal vertical plasma drifts enhancement and the
peak hmF2, particularly the electrodynamics during twilight high solar flux
conditions. |
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