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| Titel |
Three dimensional Particle-in-Cell (PIC) simulations of the 67P environment |
| VerfasserIn |
Andrey Divin, Jan Deca, Pierre Henri, Mihaly Horanyi, Stefano Markidis, Giovanni Lapenta, Vyacheslav Olshevsky, Anders Eriksson |
| 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 |
250138516
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| Publikation (Nr.) |
 EGU/EGU2017-1556.pdf |
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| Zusammenfassung |
| ESA’s Rosetta orbiter spacecraft escorted comet 67P∕Churyumov-Gerasimenko for two
years, carrying 21 scientific instruments. Five of those were dedicated to plasma
measurements. The mission revealed for the first time, and in unprecedented detail, the
fascinating evolution of a comet and its interaction with our Sun as it races along its 6.45yr
elliptical orbit around the Sun.
Using a self-consistent 3-D fully kinetic electromagnetic particle-in-cell approach, we focus
on the global cometary environment and, in particular, on the collisionless electron-kinetic
interaction. We include cometary ions and electrons produced by the ionization of the
outgassing cometary atmosphere in addition to the solar wind ion and electron plasma flow.
We approximate mass-loading of the cold cometary ion and electron populations using a 1∕r
relation with distance to the comet with a total neutral production rate of Q = 1026
s−1.
Our simulation results disentangle for the first time the kinetic ion and electron dynamics of
the solar wind interaction with a weakly outgassing comet. The simulated global structure of
the solar wind-comet interaction confirms the results reported in hybrid simulations of the
induced cometary magnetosphere. Moreover, we show that cometary and solar
wind electrons neutralize the solar wind protons and cometary ions, respectively, in
the region of influence around the comet, representing to first order a four-fluid
behavior. The electron energy distribution close to the comet is shown to be a mix of
cometary and solar wind electrons that appear as, respectively, a thermal and a
suprathermal components. Analyzing ion and electron energy distribution functions,
and comparing with plasma measurements from ESA’s Rosetta mission to comet
67P∕Churyumov-Gerasimenko, we conclude that a detailed kinetic treatment of the electron
dynamics is critical to fully capture the complex physics of mass-loading plasmas. |
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