Effects of spacecraft outgassing and potential at Mercury |
Auteur | Fraenz Markus |
Institution | MPI Solar System Research |
Theme | Theme4 |
| Auteur(s) supplémentaire(s) | Dominique Delcourt, Lina Hadid, Yoshifumi Saito, Yuki Harada, Bruno Katra, Harald Krueger, Norbert Krupp, Nicolas Andre, Ali Varsani |
| Institution(s) supplémentaire(s) | LPP - Saclay, France; ISAS, Tokyo, Japan; IRAP, Toulouse, France; IWF, Graz, Austria. |
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Abstract | During the flybys of Mercury and Venus the ion spectrometers onboard the BepiColombo spacecraft observed enhanced fluxes of ions with energies of less than 50eV. Often these fluxes showed a characteristic double-band spectral shape in energy. We interpret these ion fluxes as being caused by ionized water molecules outgassing from the spacecraft. The double-band structure may be caused by a specific feature of the spacecraft potential: for a negatively charged spacecraft electrons will be rejected from the spacecraft and may form a negative space charge at distance given by the Debye length. This space charge may contribute to a separation of the observed ion fluxes into an inner and an outer source resulting in a double-band energy distribution. We show results of a particle-in-cell simulation supporting this interpretation. |
