Advective Process Modeling for Radiation Belt Electrons
Abstract
Relativistic electron dynamics in the radiation belts falls into two categories: diffusive processes, in which particles are scattered randomly, and advective processes, in which particles are collectively driven in one direction in energy or space. In this work, we include both effects by adding an advection term in the Fokker-Planck equation. Test-particle simulation is done in the electric and magnetic fields generated by the Lyon-Fedder-Mobarry global MHD model coupled to the Rice Convection Model with a Gallagher plasmasphere included as the zero energy channel of RCM, and the advection coefficient is calculated for three CME-shock driven storms. Then, the advection coefficient is applied to the Fokker-Planck equation with advection term and solved for phase space density time evolution. The calculation is done for March 2015, July and September 2017 CME-shock driven storms using realistic input conditions from OMNIWeb solar wind data for the LFM-RCM simulations and weighting phase space density based on measurements by Van Allen Probes, all showing inward motion of electrons on the time scale of minutes, comparable to an MeV electron drift period . The result is compared with the phase space density calculated by direct test-particle simulations in MHD fields.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFMSM41C3259L
- Keywords:
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- 2720 Energetic particles: trapped;
- MAGNETOSPHERIC PHYSICS;
- 2722 Forecasting;
- MAGNETOSPHERIC PHYSICS;
- 2774 Radiation belts;
- MAGNETOSPHERIC PHYSICS;
- 7984 Space radiation environment;
- SPACE WEATHER