1. Univ Lyon, Univ Lyon 1, ENSL, CNRS, LGL-TPE, F-69622, Villeurbanne, France.
2. Space Research Centre, University of Leicester, Leicester, United Kingdom.
3. Institut d'Astrophysique Spatiale, CNRS, Université Paris-Sud, Orsay, France.
4. Université Grenoble Alpes, CNRS, IPAG, UMR 5274, F-38041, Grenoble, France.
5. Institut Universitaire de France, Paris, France.
6. Physikalisches Institut, Sidlerstr. 5, University of Bern, 3012 Bern, Switzerland.
7. Istituto Nazionale di Astrofisica, Padova, Italy.
8. Institute of Space and Earth Exploration, University of Western Ontario, London, Canada.
9. ENSL, CNRS, LGL-TPE, University of Lyon, Lyon, France.