[1] CALTECH, Pasadena, CA 91125 USA
[2] NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA
[3] Southwest Res Inst, San Antonio, TX 78228 USA
[4] Univ Arizona, Tucson, AZ 85721 USA
[5] Johns Hopkins Univ, Appl Phys Lab, Laurel, MD 20723 USA
[6] Princeton Univ, Dept Astrophys Sci, Princeton, NJ 08540 USA
[7] Natl Observ Athens, IAASARS, Athens 15236, Greece
[8] Univ Delaware, Dept Phys & Astron, Newark, DE 19716 USA
[9] NASA HQ, Washington, DC 20024 USA
[10] Univ New Hampshire, Durham, NH 03824 USA
[11] CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA
[12] Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA
[13] Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA
[14] Imperial Coll London, Blackett Lab, London SW7 2AZ, England
[15] Queen Mary Univ London, Sch Phys & Astron, London E1 4NS, England
[16] NASA, Goddard Space Flight Ctr, Solar Syst Explorat Div, Greenbelt, MD 20771 USA
[17] Univ Michigan, Climate & Space Sci & Engn, Ann Arbor, MI 48109 USA
[18] Smithsonian Astrophys Observ, Cambridge, MA 02138 USA
[19] Univ Calif Berkeley, Berkeley, CA 94720 USA