[1] Univ Chicago, Dept Phys, Chicago, IL 60637 USA
[2] Conceptual Analyt LLC, Glenn Dale, MD 20769 USA
[3] NASA, Global Sci & Technol Inc, Astron & Solar Phys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA
[4] Univ Wisconsin, Dept Phys, Madison, WI 53706 USA
[5] Univ Chicago, Dept Astron, Chicago, IL 60637 USA
[6] NASA, SSAI, Astron & Solar Phys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA
[7] Univ Calif Davis, Dept Phys, Davis, CA 95616 USA
[8] Danish Space Res Inst, DK-2100 Copenhagen, Denmark
[9] Univ Massachusetts, Dept Astron, Amherst, MA 01003 USA