1. LPC2E CNRS CNES University of Orléans Orléans France
2. Space Sciences Laboratory University of California, Berkeley Berkeley CA USA
3. School of Physics and Astronomy University of Minnesota Minneapolis MN USA
4. Solar System Exploration Division NASA/Goddard Space Flight Center Greenbelt MD USA
5. Astrophysical and Planetary Sciences Department University of Colorado, Colorado Boulder CO USA
6. Laboratory for Atmospheric and Space Physics University of Colorado, Colorado Boulder CO USA