1. Department of Physics Augsburg College Minneapolis Minnesota USA
2. Now at Department of Physics and Astronomy University of Iowa Iowa City Iowa USA
3. Space Science Center University of New Hampshire Durham New Hampshire USA
4. Department of Physics and Astronomy Dartmouth College Hanover New Hampshire USA
5. School of Physics and Astronomy University of Minnesota Minneapolis Minnesota USA
6. Los Alamos National Laboratory Los Alamos New Mexico USA
7. NASA Goddard Space Flight Center Greenbelt Maryland USA
8. The Aerospace Corporation Los Angeles California USA