1. Department of Physics and Astronomy; University of Kansas; Lawrence KS USA
2. Southwest Research Institute; San Antonio Texas USA
3. Swedish Institute of Space Physics; Uppsala Sweden
4. Laboratoire de Physique et Chimie de l'Environnement et de l'Espace CNRS; Orléans France
5. Johns Hopkins University Applied Physics Laboratory; Laurel Maryland USA
6. Physikalisches Institut; University of Bern; Bern Switzerland