EGU General Assembly 2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

Resolving Multiscale Magnetospheric and Radiation Belt Dynamics using Global MHD, Test Particle and Fokker Planck Simulations

Ravindra Desai1,2,3, Jonathan Eastwood2, Sarah Glauert3, Richard Horne3, Joseph Eggington2, Mike Heyns2, Martin Archer2, Harley Kelly2, Lars Mejnertsen2, and Jeremy Chittenden2
Ravindra Desai et al.
  • 1Centre for Fusion, Space and Astrophysics, University of Warwick, UK
  • 2Blackett Laboratory, Imperial College London, UK
  • 3British Antarctic Survey, Cambridge, UK

The global magnetosphere represents an intricate and multi-scale system with dynamics occurring across scales ranging from metres to miles and milli-seconds to days. This represents a formidable challenge to understand, and differing plasma theories are typically applied to model the large-scale electromagnetic fields and the dynamics of the Van Allen radiation belts. This discretisation of plasma regimes, however, breaks down during extreme conditions when the magnetosphere becomes highly distorted and energetic particle dynamics vary rapidly across sub-drift timescales. To self-consistently model both short and long timescales, we combine global MHD and particle simulations with Fokker-Planck simulations to demonstrate how this presents a realistic and also necessary method to capture magnetospheric and radiation belt dynamics during severe geomagnetic storms. The global MHD simulations capture the large-scale modulations to the global magnetic and electric fields and the integrated particle simulations reveal intense acceleration processes during the compression phase and subsequent injections through the magnetotail. At relativistic energies, loss processes at low L shells are limited and the Fokker-Planck model reveals how newly accelerated radiation belt distributions evolve and persist over extended time periods. Modelling this flow of energy from the solar wind through to ring current and radiation belt populations, across both short and long time-scales, requires detailed observational constraints and we discuss how upcoming space missions will help us to holistically constrain energy transfers through our puzzling magnetosphere. 

How to cite: Desai, R., Eastwood, J., Glauert, S., Horne, R., Eggington, J., Heyns, M., Archer, M., Kelly, H., Mejnertsen, L., and Chittenden, J.: Resolving Multiscale Magnetospheric and Radiation Belt Dynamics using Global MHD, Test Particle and Fokker Planck Simulations, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-5526,, 2023.