1. Department of Physics, The Catholic University of America, Washington, DC, USA
2. Los Alamos National Laboratory, Los Alamos, NM, USA
3. Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA
4. Space Research Institute of Russian Academy of Science, Moscow, Russia
5. Laboratory of Atmospheric and Space Physics, University of Colorado, Boulder, CO, USA
6. NASA Goddard Space Flight Center, Greenbelt, MD, USA