Abstract
Discovery of very large amplitude whistler-mode waves in Earth's radiation belts
School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota, USA
School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota, USA
School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota, USA
School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota, USA
School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota, USA
NASA Goddard Space Flight Center, Greenbelt, Maryland, USA
Space Sciences Laboratory, University of California, Berkeley, California, USA
Department of Physics, University of California, Berkeley, California, USA
Space Sciences Laboratory, University of California, Berkeley, California, USA
Space Sciences Laboratory, University of California, Berkeley, California, USA
Department of Physics, Dartmouth College, Hanover, New Hampshire, USA
Downs Laboratory, California Institute of Technology, Pasadena, California, USA
Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
Laboratoire d'Etudes Spatiales et d'Instrumentation en Astrophysique, Observatoire de Paris, Meudon, France
Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, Colorado, USA
NASA Goddard Space Flight Center, Greenbelt, Maryland, USA
Institute for Geophysics and Planetary Physics, University of California, Los Angeles, California, USA
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.
Citation: (2008), Discovery of very large amplitude whistler-mode waves in Earth's radiation belts, Geophys. Res. Lett., 35, L01105, doi:10.1029/2007GL032009.
Cited By
