1. NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
2. Goddard Planetary Heliophysics Institute, University of Maryland, Baltimore County, Maryland 21250, USA
3. Department of Astronomy, University of Maryland, College Park, Maryland 20742, USA
4. Department of Physics, Imperial College London, London, United Kingdom
5. Institut de Recherche en Astrophysique et Planétologie, CNRS, UPS, CNES, Université de Toulouse, Toulouse, France
6. JAXA Institute of Space and Astronautical Science, Sagamihara, Kanagawa 252-5210, Japan
7. Department of Earth, Planetary, and Space Sciences, University of California, Los Angeles, California 90095, USA
8. Physics Department, University of New Hampshire, Durham, New Hampshire 03824, USA
9. Southwest Research Institute Durham, Durham, New Hampshire 03824, USA
10. Southwest Research Institute, San Antonio, Texas 78238, USA