Journal cover Journal topic
Annales Geophysicae An open-access journal of the European Geosciences Union
Ann. Geophys., 25, 2359-2369, 2007
© Author(s) 2007. This work is distributed
under the Creative Commons Attribution 3.0 License.
29 Nov 2007
On magnetospheric electron impact ionisation and dynamics in Titan's ram-side and polar ionosphere – a Cassini case study
K. Agren1, J.-E. Wahlund1, R. Modolo1, D. Lummerzheim2, M. Galand3, I. Müller-Wodarg3, P. Canu4, W. S. Kurth5, T. E. Cravens6, R. V. Yelle7, J. H. Waite Jr.8, A. J. Coates9, G. R. Lewis9, D. T. Young10, C. Bertucci3, and M. K. Dougherty3 1Swedish Institute of Space Physics, Box 537, 751 21 Uppsala, Sweden
2Geophysical Institute, University of Alaska, Fairbanks, AK 99775, USA
3Space and Atmospheric Physics Group, Department of Physics, Imperial College London, London SW7 2BW, UK
4Centre d'Étude des Environnements Terrestre et Planétaires/CNRS/Institut Pierre Simon Laplace, 78140 Vélizy-Villacoublay, France
5Department of Physics and Astronomy, University of Iowa, Iowa City, IA 52242, USA
6Department of Physics and Astronomy, University of Kansas, Lawrence, KS 66045, USA
7Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721, USA
8Department of Atmospheric, Oceanic and Space Sciences, University of Michigan, Ann Arbor, MI 48109, USA
9Mullard Space Science Laboratory, University College London, Holmbury St. Mary, Dorking, Surrey RH5 6NT, UK
10Southwest Research Institute, San Antonio, TX 78238, USA
Abstract. We present data from the sixth Cassini flyby of Titan (T5), showing that the magnetosphere of Saturn strongly interacts with the moon's ionosphere and exo-ionosphere. A simple electron ionisation model provides a reasonable agreement with the altitude structure of the ionosphere. Furthermore, we suggest that the dense and cold exo-ionosphere (from the exobase at 1430 km and outward to several Titan radii from the surface) can be explained by magnetospheric forcing and other transport processes whereas exospheric ionisation by impacting low energy electrons seems to play a minor role.

Citation: Agren, K., Wahlund, J.-E., Modolo, R., Lummerzheim, D., Galand, M., Müller-Wodarg, I., Canu, P., Kurth, W. S., Cravens, T. E., Yelle, R. V., J. H. Waite Jr., Coates, A. J., Lewis, G. R., Young, D. T., Bertucci, C., and Dougherty, M. K.: On magnetospheric electron impact ionisation and dynamics in Titan's ram-side and polar ionosphere – a Cassini case study, Ann. Geophys., 25, 2359-2369, doi:10.5194/angeo-25-2359-2007, 2007.
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