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| Titel |
Numerical simulation of Ganymede’s ionosphere |
| VerfasserIn |
Gianluca Carnielli, Marina Galand, Francois Leblanc, Ludivine Leclercq, Ronan Modolo |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250137758
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| Publikation (Nr.) |
 EGU/EGU2017-573.pdf |
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| Zusammenfassung |
| Ganymede is one of the four Galilean moons that orbit around Jupiter and the key moon
targeted by the JUpiter and ICy moons Explorer (JUICE) mission. Other than being the
largest moon in the solar system, it is also the only one known to generate internally a
magnetic field which is strong enough to overcome the background jovian field; thus,
the moon carves out its own magnetosphere inside that of Jupiter. In addition, at
Ganymede’s orbit the jovian plasma is sub-Alfvénic and subsonic. The interaction of
Ganymede’s magnetosphere with its surroundings therefore differs from that of
planetary magnetospheres resulting from the interaction with the super-Alfvénic
and supersonic solar wind. All this makes Ganymede a peculiar celestial body to
study.
One of the main goals of the JUICE mission is to characterize Ganymede’s exosphere,
ionosphere, and magnetosphere as well as its interaction with the jovian surrounding in great
details. Ahead of the arrival of JUICE at Jupiter, models have been developed to predict
Ganymede’s environment. Observational constraints are primarily given from Galileo and
from Earth-based telescopes. They remain limited, especially in terms of the ionospheric
number density and temperature. To address the currently poorly constrained ionospheric
environment, we have developed a test particle model of Ganymede’s plasma environment.
The model is driven by the densities of neutral species from the exospheric model of Leblanc
et al. (Icarus, 2016) and the electromagnetic field taken from the hybrid model
of Leclercq et al. (PSS, 2016). The simulation follows the motion of millions of
test particles in the environment of the moon and allows to generate maps of ion
densities, bulk velocities, and temperatures. We will present simulation outcomes for
different ions, including H+, O+, and O2+. We will also discuss how the results from
the simulations are relevant to MHD and exospheric models and in interpreting
plasma and particle data obtained by Galileo during its close flybys of Ganymede. |
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