1. School of Physics and Astronomy University of Leicester Leicester UK
2. Southwest Research Institute San Antonio TX USA
3. Physics and Astronomy Department University of Texas at San Antonio San Antonio TX USA
4. Laboratory for Atmospheric and Space Physics University of Colorado Boulder Boulder CO USA
5. Laboratoire de Physique Atmosphérique et Planétaire STAR Institute Université de Liège Liège Belgium
6. Applied Physics Laboratory The Johns Hopkins University Laurel MD USA
7. Department of Physics and Astronomy University of Iowa Iowa City IA USA