1. NASA Goddard Space Flight Center, Greenbelt, MD, USA.
2. Department of Physics, American University, Washington, DC, USA.
3. NPP/USRA, Goddard Space Flight Center, Greenbelt, MD, USA.
4. California State University, San Bernardino, Department of Physics, CA USA.
5. Royal Belgian Institute for Space Aeronomy, Brussels, Belgium.
6. University of Liege, Liege, Belgium.
7. Instituto de Astrofísica de Andalucía, Granada, Spain.
8. Open University, Milton Keynes UK.
9. Istituto di Astrofisica e Planetologia, Rome, Italy.