1. Department of Atmospheric and Oceanic Sciences; University of California; Los Angeles California USA
2. Solar-Terrestrial Environment Laboratory; Nagoya University; Nagoya Japan
3. Department of Atmospheric, Oceanic and Space Sciences; University of Michigan; Ann Arbor Michigan USA
4. Department of Earth and Space Sciences; University of California; Los Angeles California USA
5. Center for Geospace Studies; SRI International; Menlo Park California USA
6. Institut für Geophysik und Extraterrestrische Physik; Technische Universität Braunschweig; Braunschweig Germany