The energetic electron population dynamics at Jupiter, Saturn, Uranus
and Neptune as revealed by historical spacecraft observations and
physics-based models
Abstract
We review the mechanisms that shape the spatial distributions of
energetic electrons trapped in the magnetospheres of Jupiter, Saturn,
Uranus and Neptune. To determine what controls the energy and spatial
distributions throughout the different magnetospheres, we compute the
time evolution of particle distributions with the help of a diffusion
theory particle transport code that solves the governing 3-D
Fokker-Planck equation. We discuss the processes already accounted for
in our physics-based models of the outer planet electron radiation belts
but also those suspected to be missing to improve our model results. Our
theoretical modeling is guided by the analysis of particle, field and
wave data collected by Pioneer 10&11 and Galileo at Jupiter, Cassini at
Saturn, and during Voyager 2’s flyby of Uranus in January 1986 and at
Neptune in August 1989.