1. Department of Space Physics, Institute of Atmospheric Physics The Czech Academy of Sciences Prague Czech Republic
2. Faculty of Mathematics and Physics Charles University Prague Czech Republic
3. Laboratoire de Physique des Plasmas, CNRS/Ecole Polytechnique/Obs. de Paris/UPMC/Univ. Paris‐Sud Palaiseau France
4. Royal Belgian Institute for Space Aeronomy Brussels Belgium
5. Institut de Recherche en Astrophysique et Planétologie University of Toulouse/CNRS/UPS/CNES Toulouse France