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NASA Grant NNG04GN01G-01 A Global Model of the Effects of ELF/VLF Chorus Emissions on Energetic Radiation Belt Electrons PI: Umran S. Inan, Stanford University. A. B.
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NASA Grant NNG04GN01G-01A Global Model of the Effects of ELF/VLF Chorus Emissions on Energetic Radiation Belt ElectronsPI: Umran S. Inan, Stanford University A. B.
A.Spasojevic and Inan [2005] studied the relationship between ground based observations of chorus emissions from Palmer, Antarctica, global changes in the electron radiation belts as observed by SAMPEX during the series of storms from Oct 29 to Oct 31, 2003, collectively referred to as the Halloween 2003 storms. Intense chorus emission were observed across the morningside on Nov 1. These observations motivated Horne et al. [2005], to perform pitch angle and energy diffusion calculations which indicated that the observed radiation belt flux increases could be attributed to acceleration by chorus waves. B.Bortnik et al. [2006] used a numerical ray tracing code combined with suprathermal flux measurements to calculate the path-integrated Landau damping of chorus waves, originating at the magnetic equatorial plane with wave normal angles set to the Gendrin angle. Results show that waves are damped before they are able to magnetospherically reflect and thus are observed to propagate universally away from the geomagnetic equator, and also that there is a distinct minimum in wave power at half the equatorial gyrofrequency, which might explain the two-band structure of chorus. NASA Grant NNG04GN01G-01 Spasojevic, M., and U. S. Inan (2005), Ground based VLF observations near L=2.5 during the Halloween 2003 storm, Geophys. Res. Lett., 32, L21103, doi:10.1029/2005GL024377. Horne, R. B., R. M. Thorne, Y. Y. Shprits, N. P. Meredith, S. A. Glauert, A. J. Smith, S. G. Kanekal, D. N. Baker, M. J. Engebretson, J. L. Posch, M. Spasojevic, U. S. Inan, J. S. Pickett and P. M. E. Decreau (2005), Wave acceleration of electrons in the Van Allen radiation belts, Nature, 432, doi:10.1038/nature03939. Bortnik, J., U. S. Inan, and T. F. Bell (2006), Landau damping and resultant unidirectional propagation of chorus waves, Geophys. Res. Lett., in press.