1. Department of Physics and Astronomy George Mason University Fairfax Virginia USA
2. Heliospheric Laboratory NASA, Goddard Space Flight Center Greenbelt Maryland USA
3. Observatori de l'Ebre, (OE) CSIC ‐Universitat Ramon Llull Roquetes Spain
4. Department of upper atmosphere Institute of Atmospheric Physics CAS Prague Czech Republic
5. Pushkov Institute of Terrestrial Magnetism, Ionosphere and Radio‐Wave Propagation (IZMIRAN) Russian Academy of Science Moscow Russia
6. Space Science Laboratory University of Massachusetts Lowell Lowell Massachusetts USA
7. Lowell Digisonde International, LLC Lowell Massachusetts USA
8. Deceased 15 October 2016