Observational evidence for the plausible linkage of Equatorial Electrojet (EEJ) electric field variations with the post sunset F-region electrodynamics
The paper is based on a detailed observational study of the Equatorial Spread F (ESF) events on geomagnetically quiet (<I>A<sub>p</sub></I>≤20) days of the solar maximum (2001), moderate (2004) and minimum (2006) years using the ionograms and magnetograms from the m...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2009-11-01
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| Series: | Annales Geophysicae |
| Online Access: | https://www.ann-geophys.net/27/4229/2009/angeo-27-4229-2009.pdf |
| Summary: | The paper is based on a detailed observational study of the Equatorial
Spread F (ESF) events on geomagnetically quiet (<I>A<sub>p</sub></I>≤20) days of the
solar maximum (2001), moderate (2004) and minimum (2006) years using the
ionograms and magnetograms from the magnetic equatorial location of
Trivandrum (8.5° N; 77° E; dip lat ~0.5° N) in India. The
study brings out some interesting aspects of the daytime Equatorial
Electrojet (EEJ) related electric field variations and the post sunset
F-region electrodynamics governing the nature of seasonal characteristics of
the ESF phenomena during these years. The observed results seem to indicate
a plausible linkage of daytime EEJ related electric field variations with
pre-reversal enhancement which in turn is related to the occurrence of ESF.
These electric field variations are shown to be better represented through a
parameter, termed as "E", in the context of possible coupling between the E-
and F-regions of the ionosphere. The observed similarities in the gross
features of the variations in the parameter "E" and the F-region vertical
drift (<I>V<sub>z</sub></I>) point towards the potential usage of the EEJ related
parameter "E" as an useful index for the assessment of <I>V<sub>z</sub></I> prior to the
occurrence of ESF. |
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| ISSN: | 0992-7689 1432-0576 |