Equatorial westward electrojet impacting equatorial ionization anomaly development during the 6 April 2000 superstorm

Horvath, Ildiko and Lovell, Brian C. (2013) Equatorial westward electrojet impacting equatorial ionization anomaly development during the 6 April 2000 superstorm. Journal of Geophysical Research A: Space Physics, 118 11: 7398-7409. doi:10.1002/2013JA019311


Author Horvath, Ildiko
Lovell, Brian C.
Title Equatorial westward electrojet impacting equatorial ionization anomaly development during the 6 April 2000 superstorm
Journal name Journal of Geophysical Research A: Space Physics   Check publisher's open access policy
ISSN 0148-0227
2156-2202
Publication date 2013
Year available 2013
Sub-type Article (original research)
DOI 10.1002/2013JA019311
Open Access Status DOI
Volume 118
Issue 11
Start page 7398
End page 7409
Total pages 12
Place of publication Hoboken, NJ United States
Publisher Wiley-Blackwell Publishing, Inc.
Collection year 2014
Language eng
Subject 1912 Space and Planetary Science
1908 Geophysics
Abstract We investigate the forward plasma fountain and the equatorial ionosphere in the topside region during the 6 April 2000 superstorm in the Australian sector at ∼0900 LT. Space- and ground-based multi-instrument measurements, Coupled Thermosphere-Ionosphere-Plasmasphere Electrodynamics (CTIPe) simulations, and field-aligned observations comprise our results. These reveal an unusual storm development during which the eastward prompt penetration electric (E) field (PPEF) developed and operated under the continuous effects of the westward disturbance dynamo E-field (DDEF) while large-scale traveling ionospheric disturbances (TIDs) traveled equatorward and generated strong equatorward wind surges. We have identified the eastward PPEF by the superfountain effect causing the equatorial ionization anomaly (EIA)'s development with crests situated at ∼±28°N (geomagnetic) in the topside ionosphere at ∼840 km altitude. The westward DDEF's occurrence is confirmed by mapping the "anti-Sq" current system wherein the equatorial westward current created a weak long-lasting westward electrojet event. Line plots of vertical drift data tracked large-scale TIDs. Four scenarios, covering ∼3.5 h in universal time, demonstrate that the westward DDEF became superimposed on the eastward PPEF. As these E-fields of different origins became mapped into the F region, they could interact. Consequently, the eastward PPEF-related equatorial upward E × B drift became locally reduced by up to 75 m/s near the dip equator by the westward DDEF-related equatorial downward E × B drift. Meanwhile, the EIA displayed a better development as equatorial wind surges, reproduced by CTIPe, increased from 501 to 629 m/s, demonstrating the crucial role of mechanical wind effects keeping plasma density high. Key Points 6 April 2000 superstorm produced some significant westward electrojet events. PPEF developed and operated under continuous DDEF effects. Superimposed westward DDEF on eastward PPEF permitted EIA development.
Keyword Disturbance dynamo electric field
Equatorial westward electrojet
Large scale TIDs
Prompt penetration electric field
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2014 Collection
School of Information Technology and Electrical Engineering Publications
 
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