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| Titel |
Average auroral configuration parameterized by geomagnetic activity and solar wind conditions |
| VerfasserIn |
S. E. Milan, T. A. Evans, B. Hubert |
| 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 ; 28, no. 4 ; Nr. 28, no. 4 (2010-04-22), S.1003-1012 |
| Datensatznummer |
250016822
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| Publikation (Nr.) |
 copernicus.org/angeo-28-1003-2010.pdf |
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| Zusammenfassung |
| Average proton and electron auroral images are compiled from three years of
observations by the IMAGE spacecraft, binned according to concurrent KP
and upstream solar wind conditions measured by the ACE spacecraft. The solar
wind parameters include solar wind velocity, density, and pressure,
interplanetary magnetic field (IMF) magnitude and orientation, and an
estimate of the magnetopause reconnection rate. We use both (a) the overall
variation in brightness in the images and (b) the variation in location of
the aurorae with respect to the binning parameters to determine which
parameters best order the auroral response. We find that the brightness
varies by a factor of ~50 with KP, a similar amount with estimated
dayside reconnection voltage, ~15 with the IMF, ~3 with solar wind
density, ~2 with solar wind velocity, and ~5 with pressure.
Clearly, geomagnetic activity as measured by KP and auroral dynamics are
closely associated. In terms of the solar wind-magnetosphere coupling that
drives auroral dynamics, the IMF is of paramount importance in modulating
this, with solar wind speed and density playing a lesser role. Dayside
reconnection voltage, derived from the solar wind velocity and IMF magnitude
and orientation, orders the data almost as well as KP, though we find a
plateau in the auroral response between voltages of 100 and 150 kV. We also
discuss changes in configuration and overall size of the average auroral oval
with upstream conditions. |
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