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| Titel |
Generation of Birkeland Currents during IMF By: Mechanisms and theory |
| VerfasserIn |
Paul Tenfjord, Nikolai Østgaard, Kristian Snekvik, Karl Laundal, Jone Reistad, Steve Milan, Stein Haaland |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250105582
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| Publikation (Nr.) |
 EGU/EGU2015-5116.pdf |
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| Zusammenfassung |
| We investigate the role of IMF By in the generation of Birkeland Currents (BC), comparing
observations from AMPERE and MHD simulations. Observations have shown that the
intensity and position of the aurora is not always symmetric between the two hemispheres.
Asymmetric BCs arise due to non-uniform penetration of IMF BY in to the closed
magnetosphere. We investigate associated BCs, and whether asymmetric currents between
the two hemispheres can be observed. We show how asymmetrical footpoints are
produced, and how this may lead to asymmetrical BCs at conjugate points. We
also present current measurements from AMPERE that are consistent with this
picture. We argue that the induced BY produces asymmetrical Birkeland currents as a
consequence of asymmetric stress balance between the hemispheres. Such an asymmetry
will also lead to asymmetrical footpoints and asymmetries in the azimuthal flow in
the ionosphere. These phenomena should therefore be treated in a unified way. |
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