Ultra-low-frequency wave-driven diffusion of radiation belt relativistic electrons

Author
Keywords
Abstract
Van Allen radiation belts are typically two zones of energetic particles encircling the Earth separated by the slot region. How the outer radiation belt electrons are accelerated to relativistic energies remains an unanswered question. Recent studies have presented compelling evidence for the local acceleration by very-low-frequency (VLF) chorus waves. However, there has been a competing theory to the local acceleration, radial diffusion by ultra-low-frequency (ULF) waves, whose importance has not yet been determined definitively. Here we report a unique radiation belt event with intense ULF waves but no detectable VLF chorus waves. Our results demonstrate that the ULF waves moved the inner edge of the outer radiation belt earthward 0.3 Earth radii and enhanced the relativistic electron fluxes by up to one order of magnitude near the slot region within about 10 h, providing strong evidence for the radial diffusion of radiation belt relativistic electrons.
Year of Publication
2015
Journal
Nature Communications
Volume
6
Number of Pages
10096
Date Published
12/2015
URL
http://www.nature.com/doifinder/10.1038/ncomms10096
DOI
10.1038/ncomms10096