1. Space Physics Research Laboratory, University of Michigan, Ann Arbor, MI 48109, USA.
2. Institut d'Astrophysique Spatiale, CNRS-Université Paris XI, 91405 Orsay Cedex
3. Institut d'Astrophysique de Paris, CNRS, 75014 Paris, France.
4. Jet Propulsion Laboratory, Pasadena, CA 91109, USA.
5. Max-Planck-Institut für Aeronomie, D-37191 Katlenburg-Lindau, Germany.
6. Institut d'Astrophysique, Université de Liège, 4000 Liège, Belgium.
7. Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
8. Service d'Aeronomie du CNRS, Verrieres le Buisson, 91371 France.
9. LASP, University of Colorado, Boulder, CO 80309, USA.
10. Department of Physics and Astronomy, University College, London, UK.
11. Space Telescope Science Institute, Baltimore, MD 21218, USA