1. Department of Physics and Astronomy George Mason University Fairfax VA USA
2. Heliospheric Laboratory NASA Goddard Space Flight Center Greenbelt MD USA
3. Istituto Nazionale di Geofisica e Vulcanologia Roma Italy
4. Institute of Atmospheric Physics of the Czech Academy of Sciences Prague Czech Republic
5. Observatori de l’Ebre CSIC Universitat Ramon Llull Roquetes Spain
6. Lowell Digisonde International Lowell MA USA
7. Space Science Laboratory University of Massachusetts Lowell MA USA