Evolution of the Earth's Van Allen Radiation Belts

The evolution of the Earth's Van Allen Radiation Belts is being modeled by following test particle trajectories in 2D and 3D simulations using 3D magnetohydrodynamic fields from the Lyon-Fedder-Mobarry MHD code driven by measured plasma parameters from spacecraft in the solar wind upstream from Earth. Global electric and magnetic field structure and computed particle distributions in momentum and spatial location are compared with measurements from the recently launched (August 30, 2012) Van Allen Probes satellites. This work is supported by the NASA Heliophysics Directorate. Separate work on the access, trapping and loss of solar energetic protons in Earth's 'magnetosphere' is funded by NSF.