 |
| Titel |
Coupled modeling of neutral and ionized sodium in the exosphere and magnetosphere of Mercury |
| VerfasserIn |
V. Tenishev, X. Jia, M. Combi, J. Slavin, T. Zurbuchen, J. Raines, M. Rubin, T. Gombosi |
| Konferenz |
EGU General Assembly 2012
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250070417
|
|
|
|
|
|
| Zusammenfassung |
| Because of its bright emission that allows remote observations, the existence of a sodium
exosphere on Mercury has been known for more than 20 years. Produced by photo-ionization,
Na+ is the most abundant heavy ion species of the exospheric origin entering the
magnetosphere. As a result, the study of sodium (both neutral and ionized) can help to link
the dynamical processes occurring in the exosphere and magnetosphere to in situ and remote
observations. This consideration makes sodium one of the most interesting species present in
the vicinity of Mercury.
A coupled modeling of neutral and ionized sodium is a challenging problem. A large
mean free path and gyro radius makes it important to account for kinetic effects. Furthermore,
the interaction of the magnetosphere with the solar wind defines the distribution of
the electric and magnetic fields that act upon these ions and has to be considered
also.
Our exospheric Monte Carlo model preserves the kinetic nature of the evolution of the
neutral/ionized sodium population. In the numerical approach implemented for this work, we
separate the simulation of the sodium ions distribution from the calculation of the
electric/magnetic fields, which are obtained from the Michigan global MHD model of
Mercury’s magnetosphere. Such an approach cannot be considered as completely
self-consistent because the charge and current densities associated with Na+ are neglected in
the calculation of the fields.
With our model we will study both recycling of the neutral sodium atoms in order to
determine its escaping fraction as well as formation of the neutral tail, which will be used to
constrain the total source rate. By modeling Na+ ions we will derive their energy distribution
for further comparisons with in situ measurements. |
|
|
|
|
|
|