The intern’s mission will be to take charge of an existing Fokker-Planck quasi-linear diffusion code that has been developed for several years at the CEA/DAM for calculating the evolution of radiation belts. The intern will carry out physico-numerical developments in this code. These developments may concern either wave-electron interaction models, which account for the diffusion of electrons under the effect of whistler-type electromagnetic waves, through the consideration of detailed models of electromagnetic waves or the more precise resolution of resonant frequencies. We will also seek to take into account the variable and non-dipolar magnetic field during solar storms through the decoding of adiabatic invariants. A significant part of the internship will be devoted to carrying out simulations to validate them by comparison with satellite measurements recently obtained from NASA’s Van Allen Probes mission. This requires processing and integrating satellite data (initial and boundary conditions, measured reference flow profiles, etc. into the calculation code to carry out the most realistic simulations). This work is linked to space weather which aims to predict the particle environment around the Earth.