Protons are seen throughout Jupiter's magnetosphere. Where these protons come from and how they evolve is not well understood. Previous observations by the Galileo spacecraft showed that protons in the vicinity of Europa have properties consistent with charge exchange with a neutral species, which effectively removes the charged particles from the magnetosphere. Using data from the Juno spacecraft, we survey proton distributions at different energies. Although charge exchange remains a plausible explanation for the observations, another possibility is that the distribution is a result of adiabatically transporting the protons through Jupiter's magnetic field.
Publication: Proton Equatorial Pitch Angle Distributions in Jupiter's Inner Magnetosphere
June 14, 2023