Discovery of very large amplitude whistler-mode waves in Earth's radiation belts

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Read Full Article (file size: 421154 bytes) Cited by GEOPHYSICAL RESEARCH LETTERS, VOL. 35, L01105, doi:10.1029/2007GL032009, 2008 Discovery of very large amplitude whistler-mode waves in Earth's radiation belts C. Cattell School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota, USA J. R. Wygant School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota, USA K. Goetz School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota, USA K. Kersten School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota, USA P. J. Kellogg School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota, USA T. von Rosenvinge NASA Goddard Space Flight Center, Greenbelt, Maryland, USA S. D. Bale Space Sciences Laboratory, University of California, Berkeley, California, USA Department of Physics, University of California, Berkeley, California, USA I. Roth Space Sciences Laboratory, University of California, Berkeley, California, USA M. Temerin Space Sciences Laboratory, University of California, Berkeley, California, USA M. K. Hudson Department of Physics, Dartmouth College, Hanover, New Hampshire, USA R. A. Mewaldt Downs Laboratory, California Institute of Technology, Pasadena, California, USA M. Wiedenbeck Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA M. Maksimovic Laboratoire d'Etudes Spatiales et d'Instrumentation en Astrophysique, Observatoire de Paris, Meudon, France R. Ergun Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, Colorado, USA M. Acuna NASA Goddard Space Flight Center, Greenbelt, Maryland, USA C. T. Russell Institute for Geophysics and Planetary Physics, University of California, Los Angeles, California, USA Abstract During a passage through the Earth's dawn-side outer radiation belt, whistler-mode waves with amplitudes up to more than ∼240 mV/m were observed by the STEREO S/WAVES instrument. These waves are an order of magnitude larger than previously observed for whistlers in the radiation belt. Although the peak frequency is similar to whistler chorus, there are distinct differences from chorus, in addition to the larger amplitudes, including the lack of drift in frequency and the oblique propagation with a large longitudinal electric field component. Simulations show that these large amplitude waves can energize an electron by the order of an MeV in less than 0.1s, explaining the rapid enhancement in electron intensities observed between the STEREO-B and STEREO-A passage during this event. Our results show that the usual theoretical models of electron energization and scattering via small-amplitude waves, with timescales of hours to days, may be inadequate for understanding radiation belt dynamics. Received 13 September 2007; accepted 6 December 2007; published 12 January 2008. Keywords: whistler waves; electron energization; radiation belt. Index Terms: 2774 Magnetospheric Physics: Radiation belts; 2772 Magnetospheric Physics: Plasma waves and instabilities (2471); 7846 Space Plasma Physics: Plasma energization; 7867 Space Plasma Physics: Wave/particle interactions (2483, 6984). Read Full Article (file size: 421154 bytes) Cited by Citation: Cattell, C., et al. (2008), Discovery of very large amplitude whistler-mode waves in Earth's radiation belts, Geophys. Res. Lett., 35, L01105, doi:10.1029/2007GL032009. Copyright 2008 by the American Geophysical Union.

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