1. Space and Atmospheric Physics Group; Imperial College London; London UK
2. Mullard Space Science Laboratory; University College London; Surrey UK
3. Centre for Planetary Sciences; University College London; London UK
4. Max Planck Institute for Solar System Research; Katlenburg-Lindau Germany
5. Department of Physics and Astronomy; University of Leicester; Leicester UK
6. Applied Physics Laboratory; Johns Hopkins University; Baltimore Maryland USA
7. Los Alamos National Laboratory; Los Alamos New Mexico USA
8. Institute of Geophysics and Planetary Physics; University of California; Los Angeles California USA
9. Department of Physics and Astronomy; University College London; London UK