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| Titel |
Influence of the solar EUV flux on the Martian plasma environment |
| VerfasserIn |
R. Modolo, G. M. Chanteur, E. Dubinin, A. P. Matthews |
| 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 ; 23, no. 2 ; Nr. 23, no. 2 (2005-02-28), S.433-444 |
| Datensatznummer |
250015150
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| Publikation (Nr.) |
 copernicus.org/angeo-23-433-2005.pdf |
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| Zusammenfassung |
| The interaction of the solar wind with the Martian atmosphere and ionosphere
is investigated by using three-dimensional, global and multi-species hybrid
simulations. In the present work we focus on the influence of the solar EUV
flux on the Martian plasma environment by comparing simulations done for
conditions representative of the extrema of the solar cycle. The dynamics of
four ionic species (H+, He++, O+, O2+), originating either
from the solar wind or from the planetary plasma, is treated fully
kinetically in the simulation model in order to characterize the distribution
of each component of the plasma, both at solar maximum and at solar minimum.
The solar EUV flux controls the ionization frequencies of the exospheric
species, atomic hydrogen and oxygen, as well as the density, the temperature,
and thus the extension of the exosphere. Ionization by photons and by
electron impacts, and the main charge exchange reactions are
self-consistently included in the simulation model. Simulation results are in
reasonable agreement with the observations made by Phobos-2 and Mars Global
Surveyor (MGS) spacecraft: 1) the interaction creates a cavity, void of solar
wind ions (H+, He++), which depends weakly upon the phase of the solar
cycle, 2) the motional electric field of the solar wind flow creates strong
asymmetries in the Martian environment, 3) the spatial distribution of the
different components of the planetary plasma depends strongly upon the phase
of the solar cycle. The fluxes of the escaping planetary ions are computed
from the simulated data and results for solar maximum are compared with
estimates based on the measurements made by experiments ASPERA and TAUS
on board Phobos-2. |
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