1. Department of Physics and Astronomy; Dartmouth College; Hanover New Hampshire USA
2. Department of Physics; Augsburg College; Minneapolis Minnesota USA
3. Space Sciences Laboratory; University of California; Berkeley California USA
4. Mullard Space Science Laboratory; University College London; Dorking UK
5. Group ISR-1; Los Alamos National Laboratory; Los Alamos New Mexico USA
6. LPC2E, UMR 6115; CNRS; Orléans France
7. School of Physics and Astronomy; University of Minnesota; Minneapolis Minnesota USA
8. CESR; University of Toulouse, UPS; Toulouse France
9. UMR 5187; CNRS; Toulouse France