1. Department of Physics and Astronomy; University of Leicester; Leicester UK
2. Laboratory for Planetary and Atmospheric Physics; University of Liège; Liège Belgium
3. Swedish Institute of Space Physics-Uppsala; Uppsala Sweden
4. Department of Physics; Lancaster University; Lancaster UK
5. Mullard Space Science Laboratory; University College London; Dorking UK
6. Centre for Planetary Sciences at UCL/Birkbeck; London UK
7. Blackett Laboratory; Imperial College; London UK
8. Department of Physics and Astronomy; University of Iowa; Iowa City Iowa USA
9. Applied Physics Laboratory; Johns Hopkins University; Laurel Maryland USA