1. Swedish Institute of Space Physics Uppsala Sweden
2. Department of Physics and Astronomy Uppsala University Uppsala Sweden
3. University of Colorado Boulder Boulder Colorado USA
4. Mullard Space Science Laboratory University College London London UK
5. Centre for Planetary Sciences University College London/Birkbeck London UK
6. Space Science and Engineering Division Southwest Research Institute San Antonio Texas USA
7. Department of Physics and Astronomy University of Texas at San Antonio San Antonio Texas USA