1. Space Science Center; University of New Hampshire; Durham New Hampshire USA
2. Space and Atmospheric Physics, Blackett Laboratory; Imperial College London; London UK
3. Mullard Space Science Laboratory; University College London; Dorking UK
4. Institute of Geophysics and Planetary Physics; University of California; Los Angeles California USA
5. Swedish Institute of Space Physics; Uppsala Sweden
6. Max Planck Institute for Extraterrestrial Physics; Garching Germany