University of Iowa, Department of Physics and Astronomy, Iowa City, IA 52242, USA
University of Iowa, Department of Physics and Astronomy, Iowa City, IA 52242, USA
University of Iowa, Department of Physics and Astronomy, Iowa City, IA 52242, USA; Inst. Atmospheric Physics, Charles University, Prague, CZ-18000, Czech Republic
University of Iowa, Department of Physics and Astronomy, Iowa City, IA 52242, USA
University of Iowa, Department of Physics and Astronomy, Iowa City, IA 52242, USA
University of Iowa, Department of Physics and Astronomy, Iowa City, IA 52242, USA