1. Hermanus Magnetic Observatory; Hermanus South Africa
2. School of Physics; University of KwaZulu-Natal; Durban South Africa
3. Space Research Group; Eötvös University; Budapest Hungary
4. Research Group for Geology, Geophysics and Space Sciences; Eötvös University; Budapest Hungary
5. Space and Plasma Physics, School of Electrical Engineering; Royal Institute of Technology; Stockholm Sweden
6. Department of Astronomy and Space Physics; Uppsala University; Uppsala Sweden
7. Department of Physics; University of Otago; Dunedin New Zealand