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| Titel |
Access of solar wind electrons into the Martian magnetosphere |
| VerfasserIn |
E. M. Dubinin, M. Fraenz, J. Woch, E. Roussos, J. D. Winningham, R. A. Frahm, A. Coates, F. Leblanc, R. Lundin, S. Barabash |
| 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 ; 26, no. 11 ; Nr. 26, no. 11 (2008-11-12), S.3511-3524 |
| Datensatznummer |
250016290
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| Publikation (Nr.) |
 copernicus.org/angeo-26-3511-2008.pdf |
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| Zusammenfassung |
| Electrons with energy of ~40–80 eV measured by the instrument
ASPERA-3 on Mars Express and MAG-ER onboard Mars Global Surveyor are
used to trace an access of solar wind electrons into the Martian
magnetosphere. Crustal magnetic fields create an additional
protection from solar wind plasma on the dayside of the Southern Hemisphere by
shifting the
boundary of the induced magnetosphere (this boundary is often refereed as the magnetic pileup
boundary) above strong crustal sources to ~400 km as compared to the Northern Hemisphere.
Localized
intrusions through cusps are also observed. On the nightside an
access into the magnetosphere depends on the IMF orientation.
Negative values of the ByIMF component assist the access to the
regions with strong crustal magnetizations although electron fluxes
are strongly weakened below ~600 km. A precipitation pattern
at lower altitudes is formed by intermittent regions with reduced
and enhanced electron fluxes. The precipitation sites are
longitudinally stretched narrow bands in the regions with a strong
vertical component of the crustal field. Fluxes ≥109 cm−2 s−1
of suprathermal electrons necessary to explain the observed
aurora emissions are maintained only for the periods with enhanced
precipitation. The appearance of another class of electron
distributions – inverted V structures, characterized by peaks on
energy spectra, is controlled by the IMF. They are clustered in the
hemisphere pointed by the interplanetary electric field that
implies a constraint on their origin. |
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