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Titel |
Aurora and open magnetic flux during isolated substorms, sawteeth, and SMC events |
VerfasserIn |
A. D. DeJong, X. Cai, R. C. Clauer, J. F. Spann |
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 ; 25, no. 8 ; Nr. 25, no. 8 (2007-08-29), S.1865-1876 |
Datensatznummer |
250015902
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Publikation (Nr.) |
copernicus.org/angeo-25-1865-2007.pdf |
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Zusammenfassung |
Using Polar UVI LBHl and IMAGE FUV WIC data, we have compared the auroral
signatures and polar cap open flux for isolated substorms, sawteeth
oscillations, and steady magnetospheric convection (SMC) events. First, a
case study of each event type is performed, comparing auroral signatures and
open magnetic fluxes to one another. The latitude location of the auroral
oval is similar during isolated substorms and SMC events. The auroral
intensity during SMC events is similar to that observed during the expansion
phase of an isolated substorm. Examination of an individual sawtooth shows
that the auroral intensity is much greater than the SMC or isolated substorm
events and the auroral oval is displaced equatorward making a larger polar
cap. The temporal variations observed during the individual sawtooth are
similar to that observed during the isolated substorm, and while the change
in polar cap flux measured during the sawtooth is larger, the percent change
in flux is similar to that measured during the isolated substorm. These
results are confirmed by a statistical analysis of events within these three
classes. The results show that the auroral oval measured during individual
sawteeth contains a polar cap with, on average, 150% more magnetic flux than
the oval measured during isolated substorms or during SMC events. However,
both isolated substorms and sawteeth show a 30% decrease in polar cap
magnetic flux during the dipolarization (expansion) phase. |
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