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| Titel |
A Solar Wind driver for the atmospheric super-rotation at Venus |
| VerfasserIn |
Rickard Lundin, S. Barabash, H. Perez-de Tejada, J. A. Sauvaud |
| 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 |
250034470
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| Zusammenfassung |
| ASPERA plasma flow measurements from the ESA Venus Express mission display a strong
nightside lateral flow of ionospheric ions, converging to a vortex-like structure in the Venus
polar ionosphere. The flow is consistent with the lateral solar wind flow around Venus. The
vortex is displaced slightly antisunward of the venusian geographic pole, the ionospheric ions
moving with 3-10 km/s in the direction of the super-rotating atmosphere of Venus. The
average O+ flux in the vortex is -1-
1012 (ions/(m2 s). The ionospheric ion vortex is a feature
that dominates the ion flow pattern at Venus. In fact the flux of the ion escape into the tail
is of the order one third of the total flux of ionospheric ions. The super-rotating
atmosphere, the velocity increasing with height, has been an enigma in atmospheric
science. The high flow velocities of ionospheric ions, in the same direction as the
internal atmospheric flow, is therefore consistent with a solar wind driven atmospheric
super-rotation at Venus, the topside atmospheric wind maintained by ion-neutral collisions. |
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