Affiliation: | a Department of Physics and Astronomy, Johns Hopkins University, Charles and 34th Streets, Baltimore, MD 21218-2695, USA b Space Science & Engineering Division, Southwest Research Institute, 1050 Walnut Street, Suite 400, Boulder, CO 80302, USA c Space Science & Engineering Division, Southwest Research Institute, 6220 Culebra Road, San Antonio, TX 78238, USA d Department of Astronomy, University of Maryland, College Park, MD 20742-2421, USA e Service d'Aéronomie du CNRS, BP 3, F-91371 Verrières-le-Buisson, France f Observatoire Midi-Pyrénées, 14, avenue E. Belin, F-31400 Toulouse, France |