1. Department of Physics; Umeå University; Umeå Sweden
2. Institute for Space Sciences; Bucharest Romania
3. Swedish Institute of Space Physics; Uppsala Sweden
4. Max-Planck-Institut für Extraterrestrische Physik; Garching Germany
5. Space Science Center, Institute for the Study of Earth, Oceans, and Space; University of New Hampshire; Durham New Hampshire USA
6. CESR-CNRS; Toulouse France