[1] Catholic Univ Amer, Dept Phys, Inst Astrophys & Computat Sci, Washington, DC 20064 USA
[2] NASA, Astron & Solar Phys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA
[3] NASA, Raytheon ITSS, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA