Energetic Electron Distributions Near the Magnetic Equator in the Jovian Plasma Sheet and Outer Radiation Belt Using Juno Observations

We present the average distribution of energetic electrons in Jupiter's plasma sheet and outer radiation belt near the magnetic equator during Juno's first 29 orbits. Juno observed a clear decrease of magnetic field amplitude and enhancement of energetic electron fluxes over 0.1-1,000 keV energies when traveling through the plasma sheet. In the radiation belts, Juno observed pancake-shaped electron distributions with high fluxes at ∼90° pitch angle and whistler-mode waves. Our survey indicates that the statistical electron flux at each energy tends to increase from M=80 to M=8. The equatorial pitch angle distributions are isotropic or field-aligned in the plasma sheet and gradually become pancake-shaped at M<15. The electron phase space density gradients at μ=100-30,000 MeV/G are relatively small at M>30 and become positive over 8<M<30, suggesting the dominant role of adiabatic radial transport at higher M shells, and the possible loss processes at lower M shells.