Data-driven empirical/physical-based model for radiation belt electrons
Abstract
There are several major contributors to increase/decrease flux of energetic electrons in Earth's radiation belt. In global scale, radial diffusion process by Ultra Low Frequency waves transports radiation belt electrons in the radial direction by conserving the first adiabatic invariant, which leads to energy change of the electrons by breaking third adiabatic invariant. On the other hand, in local scale, wave scattering process by whistler chorus waves breaks the first adiabatic invariant, which may contribute to flux enhancement and/or depletion. Both global and local processes have important roles to make highly variable radiation belt. It is suggested that several empirical/physical models are required in order to reproduce highly variable flux distribution of energetic electrons in the radiation belt. In order to reproduce highly variable radiation belt electrons in three-dimensional global scale, we are developing an empirical/physical-based model for the radiation belt in the inner magnetosphere. The model utilizes a guiding-centered test particle method for energetic electrons in electromagnetic fields produced by empirical and/or physical models. All empirical models integrated into the radiation belt model can be driven by the solar wind parameters, such as the solar wind speed, density, dynamic pressure, and interplanetary magnetic fields. Physical models utilize outputs from the empirical models to reproduce dynamics of the radiation belt. In this model, guiding-center motion in the background electromagnetic fields is coupled with radial diffusion process to represent flux variation in global scale. On the other hand, particle scattering model in local scale coupled with wave enhancement model represents electron scattering that breaks the first adiabatic invariant through resonant process. The advantage of the physical-based wave scattering model is that nonlinear scattering process, like phase-trapping process, can be included in the radiation belt model, which cannot be reproduced in quasi-linear models. We will introduce a concept and resent update on the empirical/physical-based model for outer radiation belt.
- Publication:
-
43rd COSPAR Scientific Assembly. Held 28 January - 4 February
- Pub Date:
- January 2021
- Bibcode:
- 2021cosp...43E2283S