Simulation of Radiation Belt Dynamics Driven by Solar Wind Variations

TitleSimulation of Radiation Belt Dynamics Driven by Solar Wind Variations
Publication TypeBook Chapter
Year of Publication1999
AuthorsHudson, MK, Elkington, SR, Lyon, JG, Goodrich, CC, Rosenberg, TJ
EditorBurch, L, Carovillano, L, Antiochos, K
Book TitleSun-Earth Plasma Connections
Volume109
Pagination171 - 182
PublisherAmerican Geophysical Union
CityWashington, D. C.
AbstractThe rapid rise of relativistic electron fluxes inside geosynchronous orbit during the January 10-11, 1997, CME-driven magnetic cloud event has been simulated using a relativistic guiding center test particle code driven by out-put from a 3D global MHD simulation of the event. A comparison can be made of this event class, characterized by a moderate solar wind speed (< 600 km/s), and those commonly observed at the last solar maximum with a higher solar wind speed and shock accelerated solar energetic proton component. Relativistic electron flux increase occurred over several hours for the January event, during a period of prolonged southward IMF Bz more rapidly than the 1-2 day delay typical of flux increases driven by solar wind high speed stream interactions. Simulations of the January event captured the flux increase around L=4 observed by GPS satellites, following the flux decrease associated with build up of the ring current. Analysis of ULF oscillations in the simulation data shows toroidal mode structure commensurate with electron drift periods in the 0.2 - 3.2 MeV energy range between L = 3 - 9. Oscillations in the same frequency range seen in riometer and magnetometer data suggest that resonance with ULF oscillations may play a role in energizing relativistic electrons. The radial electric field component of toroidal oscillations at the electron drift period provides a mechanism for continuous acceleration of relativistic electrons in the absence of a large inductive electric field impulse
URLhttp://onlinelibrary.wiley.com/doi/10.1029/GM109p0171/summary
DOI10.1029/GM10910.1029/GM109p0171


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