Department of Physics, University of Texas at Arlington, Arlington, TX 76019, USA
Department of Earth and Space Sciences, University of California at Los Angeles, Los Angeles, CA 90095, USA
Space Sciences Laboratory, University of California at Berkeley, Berkeley, CA 94720, USA
Space Sciences Laboratory, University of California at Berkeley, Berkeley, CA 94720, USA
Institut für Geophysik und extraterrestrische Physik der Technischen Universität Braunschweig, Mendelssohnstrasse 3, D-38106, Braunschweig, 38106, Germany