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Titel |
Monte-Carlo modelling of hot particles in Venus upper atmosphere |
VerfasserIn |
Hannes Gröller, Helmut Lammer, Herbert I. M. Lichtenegger, Valery Shematovich, Yuri Kulikov, Martin Pfleger |
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 |
250041932
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Zusammenfassung |
Suprathermal oxygen atoms produced by means of photochemical reactions in planetary
thermospheres can play an important role for the escape of atmospheric species by direct (i.e.
thermal) or indirect (e.g. pick up) processes. In either case the non-thermal energy
distribution functions at the exobase must be known in order to estimate the hot oxygen
exosphere density profiles. For this purpose hot particles generated via dissociative
recombination of O2+ are traced along their stochastic way through the thermosphere of
Venus by using a 3D Monte-Carlo model and the kinetics and transport characteristics of
these particles are determined. The simulation considers the collision of the suprathermal
particles with the background gas, energy transfer, and the tracing of secondary and cascaded
hot atoms, which are generated in collisions of the hot particles with ambient constituents. A
non-linear electron dissociative recombination coefficient as well as energy and mass
dependent collision cross sections and their corresponding scattering angles (forward
scattering) are also taken into account. The exosphere density is obtained from the
corresponding energy density and angular distribution at the exobase altitude by using a test
particle model which traces the ballistic trajectories of hot O atoms in the exosphere. |
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