HR: 0800h
AN: SM21A-0334    [Abstracts]
TI: Quantifying ULF Waves in the Inner Magnetosphere and Their Effects on Radiation Belt Electrons
AU: * Huang, C
EM: hcl@bu.edu
AF: Center for Space Physics, Boston University, 725 Commonwealth Avenue, Boston, MA 02215, United States
AU: Spence, H E
EM: spence@bu.edu
AF: Center for Space Physics, Boston University, 725 Commonwealth Avenue, Boston, MA 02215, United States
AU: Singer, H J
EM: Howard.Singer@noaa.gov
AF: Space Environment Center, NOAA, 325 Broadway, Boulder, CO 80305, United States
AU: Elkington, S R
EM: scot.elkington@lasp.colorado.edu
AF: Laboratory for Atmospheric and Space Physics, University of Colorado, 1234 Innovation Drive, Boulder, CO 80303, United States
AB: Identifying and determining the acceleration, transport, and loss mechanisms that populate, maintain, and modify radiation belt electrons remains one of the major open scientific questions in the magnetospheric community. We demonstrate new ways to characterize and study the ultra-low-frequency (ULF) waves in the inner magnetosphere that are critical for controlling radiation belt electron dynamics. A statistical study of Geosynchronous Operational Environmental Satellite (GOES) magnetic field data reveals the characteristics of ULF wave spectra at geosynchronous orbit during different solar wind conditions and levels of geomagnetic activity. In order to understand the dynamic behavior of radiation belt electrons in ULF wave fields, a global, realistic, self-consistent, and time-dependent magnetospheric model is needed. Therefore, we compare Lyon- Fedder-Mobarry (LFM) code predictions with geosynchronous measurements to assess model performance and to quantify the field fluctuations in the inner magnetosphere. Next, the dynamics of radiation belt electrons are simulated using global magnetic and electric fields from the LFM code, driven by idealized solar wind over a range of velocities. We follow the trajectories of electrons, starting at different local times and radii for the same first adiabatic invariant, to understand their transport and energization through collective wave-particle interactions. Finally, we quantify the ULF wave effects on radiation belt electrons by calculating the radial diffusion coefficients from the LFM simulation results. Our results demonstrate that the derived coefficients as a function of solar wind velocity are comparable to observational results after normalizing for wave power.
DE: 2730 Magnetosphere: inner
DE: 2740 Magnetospheric configuration and dynamics
DE: 2752 MHD waves and instabilities (2149, 6050, 7836)
DE: 2753 Numerical modeling
DE: 2774 Radiation belts
SC: SPA-Magnetospheric Physics [SM]
MN: 2007 Fall Meeting