Distinctive plasma density features of the topside ionosphere and their electrodynamics investigated during southern winter

Horvath, Ildiko and Lovell, Brian C. (2009) Distinctive plasma density features of the topside ionosphere and their electrodynamics investigated during southern winter. Journal of Geophysical Research - Space Physics, 114 A01304: . doi:10.1029/2008JA013683


Author Horvath, Ildiko
Lovell, Brian C.
Title Distinctive plasma density features of the topside ionosphere and their electrodynamics investigated during southern winter
Journal name Journal of Geophysical Research - Space Physics   Check publisher's open access policy
ISSN 0148-0227
Publication date 2009-01-16
Year available 2009
Sub-type Article (original research)
DOI 10.1029/2008JA013683
Volume 114
Issue A01304
Total pages 20
Place of publication Washington, DC, United States
Publisher American Geophysical Union
Collection year 2010
Language eng
Subject 810199 Defence not elsewhere classified
020107 Mesospheric, Ionospheric and Magnetospheric Physics
C1
Abstract This study utilizes a novel technique to map the Defense Meteorological Satellite Program (DMSP) data across the two hemispheres to learn about the morphology and plasma composition of the topside ionosphere, and the underlying ionospheric dynamics. In the southern winter hemisphere, the regional maps tracked a heavy-ion (Ni-O+) trough,aurora zone, polar hole, and large plasma density depletion. The latter appeared in the region of the South Atlantic Magnetic Anomaly (SAMA). The electron temperature (Te) map detected the thermal characteristics of these features, while the plasma drifts and flux maps tracked their dynamics. Results show that there were special electrodynamic effects in the SAMA region due to the low magnetic field and high conductivity. These increased the vertical downward (VZ) and the westward (VY) drifts. Independently, the VZ and VY maps registered the affected area that was depleted in heavy ions and rich in light ions. Some field-aligned profiles tracked the impact of these SAMA effects on the heavy-ion trough, which was a stagnation trough and appeared markedly differently at different longitudes. At trough latitudes ((56 ± 4)S (geomagnetic) when Dstav = 0 nT), the elevated electron temperatures forming a Te peak indicated subauroral heating effects. A statistical study modeled the magnetic activity dependence of the Te peak’s magnitude and location and revealed their linear correlation with the activity level. Statistically, the Te peak increased [10.226 ± 1.355]K and moved equatorward [0.051 ± 0.009] (geomagnetic) per 1 nT decrease in the averaged Dst index. Per 1 nT increase in the averaged AE index, its magnitude increased [1.315 ± 0.444]K and the equatorward movement was [0.014 ± 0.003].
Keyword Electron temperature enhancement
Interplanetary magnetic field
High latitude ionoshpere
Auroral red arcs
Equatorial Ionosphere
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: 2010 Higher Education Research Data Collection
School of Information Technology and Electrical Engineering Publications
 
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Created: Tue, 28 Apr 2009, 17:16:58 EST by Dr Ildiko Horvath on behalf of School of Information Technol and Elec Engineering