1. The Johns Hopkins University Applied Physics Laboratory Laurel MD USA
2. Department of Physical and Chemical Sciences University of L'Aquila L'Aquila Italy
3. Consorzio Area di Ricerca in Astrogeofisica L'Aquila Italy
4. Space Sciences Department The Aerospace Corporation Los Angeles CA USA
5. Department of Atmospheric and Oceanic Sciences University of California Los Angeles CA USA
6. Department of Physics and Astronomy University of Iowa Iowa City IA USA
7. School of Physics and Astronomy University of Minnesota, Twin Cities Minneapolis MN USA
8. Japan Aerospace Exploration Agency Tsukuba Japan