1. Department of Astrophysical and Planetary Sciences; University of Colorado Boulder; Boulder Colorado USA
2. Laboratory of Atmospheric and Space Sciences; University of Colorado Boulder; Boulder Colorado USA
3. Department of Physics; University of Colorado Boulder; Boulder Colorado USA
4. The Blackett Laboratory; Imperial College London; London UK
5. Physics Department; University of New Hampshire; Durham New Hampshire USA
6. Southwest Research Institute; San Antonio Texas USA
7. Royal Institute of Technology; Stockholm Sweden
8. Swedish Institute of Space Physics; Uppsala Sweden
9. Department of Earth and Space Sciences; University of California; Los Angeles California USA
10. NASA Goddard Space Flight Center; Greenbelt Maryland USA
11. Department of Physics; University of Maryland; College Park Maryland USA
12. Institut de Recherche en Astrophysique et Planétologie; Université de Toulouse; Toulouse France
13. Centre National de la Recherche Scientifique; Toulouse France
14. Laboratoire de Physique des Plasmas; Palaiseau France
15. Space Sciences Laboratory; University of California; Berkeley California USA
16. Bartol Research Institute, Department of Physics and Astronomy; University of Delaware; Newark Delaware USA
17. Department of Physics and Astronomy; West Virginia University; Morgantown West Virginia USA
18. Space Research Institute; Austrian Academy of Sciences; Graz Austria
19. Department of Physics and Astronomy; University of California; Los Angeles California USA