1. Johns Hopkins University Applied Physics Laboratory; Laurel Maryland USA
2. Department of Physics and Astronomy; Dartmouth College; Hanover New Hampshire USA
3. Department of Physics and Astronomy; University of Iowa; Iowa City Iowa USA
4. School of Physics and Astronomy; University of Minnesota, Twin Cities; Minneapolis Minnesota USA
5. Space Sciences Laboratory; University of California; Berkeley California USA
6. Department of Physics; Auburn University; Auburn Alabama USA
7. Department of Physics and Institute for the Study of Earth, Oceans and Space; University of New Hampshire; Durham New Hampshire USA
8. Solar System Exploration Division; Goddard Space Flight Center; Greenbelt Maryland USA