1. Space Science and Engineering; Southwest Research Institute; San Antonio Texas USA
2. Applied Physics Laboratory; The Johns Hopkins University; Laurel Maryland USA
3. Inst. fur Experimentelle und Angewandte Physik; University of Kiel; Kiel Germany
4. Max Planck Institute for Solar System Research; Katlenburg-Lindau Germany
5. Department of Physics and Space Sciences; Florida Institute of Technology; Melbourne Florida USA
6. Goddard Space Flight Center; NASA; Greenbelt Maryland USA