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| Titel |
Auroral asymmetries in the conjugate hemispheres during substorm onset and expansion phase. |
| VerfasserIn |
Nikolai Østgaard, Beate Krøvel Humberset, Karl Magnus Laundal, Harald U. Frey, J. B. Sigwarth, Arne Aasnes, James Weygand |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250035590
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| Zusammenfassung |
| Simultaneous global imaging in the ultraviolet wavelengths by the IMAGE and Polar satellites
are used to examine the dynamics of the auroral substorm.
When mapped onto apex coordinates, the auroral features in the conjugate hemispheres
are usually found to be asymmetric.
Earlier studies have demonstrated that the asymmetries of substorm onset locations in the
two hemispheres are controlled by the IMF clock angle.
In this paper we follow similar features in the two hemispheres during expansion phase of
several substorms. We find that the asymmetry induced by the IMF clock angle at substorm
onset disappear during the expansion phase implying that magnetic field lines with
asymmetric footpoints are rectified during expansion phase. Various mechanism that can
re-establish the symmetric aurora are discussed. |
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