1. Space Research Institute; Russian Academy of Sciences; Moscow Russia
2. Skobeltsyn Institute of Nuclear Physics; Lomonosov Moscow State University; Moscow Russia
3. Polar Geophysical Institute, Kola Scientific Center; Russian Academy of Sciences; Apatity Russia
4. Max Planck Institute for Solar System Research; Katlenburg-Lindau Germany
5. Space Research and Technologies Institute; Bulgarian Academy of Sciences; Sofia Bulgaria
6. Space Science Institute, School of Astronautics; Beihang University; Beijing China
7. Institute de Recherche en Astrophysique et Planétologie; Toulouse France
8. Mullard Space Science Laboratory; University College London; London UK