1. Department of Space Physics; Institute of Atmospheric Physics; Prague Czech Republic
2. Faculty of Mathematics and Physics; Charles University; Prague Czech Republic
3. Department of Physics and Astronomy; University of Iowa; Iowa City Iowa USA
4. Mullard Space Science Laboratory; Holmbury St. Mary UK
5. LPC2E, CNRS; Orléans France
6. Station de Radioastronomie de Nancay; Observatoire de Paris, CNRS; Nancay France
7. Laboratoire de Physique des Plasmas; CNRS; Palaiseau France
8. Laboratoire Atmosphères, Milieux; Observations Spatiales, CNRS; Paris France
9. Institute of Geophysics and Planetary Physics; University of California; Los Angeles California USA
10. Physical Sciences Division, British Antarctic Survey; Natural Environment Research Council; UK