1. High Altitude Observatory; National Center for Atmospheric Research; Boulder Colorado USA
2. Now at Department of Physics; Lancaster University; Lancaster UK
3. North West Research Associates, Inc.; Redmond Washington USA
4. International Center for Space Weather Science and Education; Kyushu University; Fukuoka Japan
5. Department of Physics; University of Ilorin; Ilorin Nigeria
6. National Space Research and Development Agency; Abuja Nigeria
7. National Institute of Information and Communications Technology; Koganei Japan