Ionising sources in the coma of 67P probed by Rosetta - INSU - Institut national des sciences de l'Univers Accéder directement au contenu
Communication Dans Un Congrès Année : 2017

Ionising sources in the coma of 67P probed by Rosetta

Kevin Heritier
  • Fonction : Auteur
Marina Galand
  • Fonction : Auteur
Anders Eriksson
Elias Odelstad
  • Fonction : Auteur
Kathrin Altwegg
  • Fonction : Auteur
Arnaud Beth
  • Fonction : Auteur
Thomas Broiles
  • Fonction : Auteur
Jim Burch
  • Fonction : Auteur
Christopher Carr
  • Fonction : Auteur
Emanuele Cupido
  • Fonction : Auteur
Karl-Heinz Glassmeier
  • Fonction : Auteur
Hans Nilsson
  • Fonction : Auteur
Ingo Richter
  • Fonction : Auteur
Martin Rubin
  • Fonction : Auteur
Erik Vigren
  • Fonction : Auteur

Résumé

An ionospheric model has been developed in order to quantify the ion number density in the coma of 67P/Churyumov-Gerasimenko. The model is driven by Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA)/Cometary Pressure Sensor (COPS) neutral density and assumes isentropic expansion for the neutral density profile. The two ionisation sources considered are photo-ionisation by solar extreme ultraviolet (EUV) radiation and electron-impact ionisation. The EUV radiation is estimated from fluxes measured by the Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED)/ Solar EUV Experiment (SEE), taking into account the phase shift and the heliocentric distance ratio; between Earth and comet 67P. The electron-impact ionisation production rates are derived from Rosetta Plasma Consortium (RPC)-Ion and Electron Sensor (IES) integrated electron fluxes and corrected for the S/C potential from RPC/LAngmuir Probe (LAP) measurements. Our results are compared with in situ measurements of the plasma density from RPC-Mutual Impedance Probe (MIP) and RPC-LAP. There is a good agreement between the modelled and RPC observed electron densities. The ionospheric model enables to distinguish the relative contributions of the different sources to the total cometary plasma. At high heliocentric distances, electron-impact ionisation becomes the dominant ionisation source and is enhanced over the winter hemisphere. As the solar activity has decreased since the beginning of the mission in 2014, the relative importance of photo-ionisation has decreased as well. However, at low heliocentric distances, photo-ionisation seems to be the most dominant ionising source, in particular through the perihelion period in summer 2015.
Fichier principal
Vignette du fichier
EGU2017-1269.pdf (38.61 Ko) Télécharger le fichier
Origine : Fichiers éditeurs autorisés sur une archive ouverte

Dates et versions

insu-03568160 , version 1 (12-02-2022)

Licence

Paternité

Identifiants

Citer

Kevin Heritier, Marina Galand, Pierre Henri, Anders Eriksson, Elias Odelstad, et al.. Ionising sources in the coma of 67P probed by Rosetta. 19th EGU General Assembly, Apr 2017, Vienne, Austria. pp.1269. ⟨insu-03568160⟩
42 Consultations
0 Téléchargements

Partager

Gmail Facebook X LinkedIn More