Space Physics Seminar Winter-2018

Juno is the first spacecraft to explore the low-altitude polar magnetosphere of the Jupiter. The ultraviolet spectrometer instrument on board Juno showed extensive diffuse aurora observed equatorward of the main auroral oval. In the region where these diffuse auroral emissions were observed, the JEDI and JADE particle instruments measured nearly full loss cone distributions for the downward-going electrons over energies of 0.1–700 keV, but very few upward-going electrons. The coordinated measurements of diffuse aurora and energetic particle precipitation provide the direct evidence of the origin of Jupiter’s diffuse aurora. Interestingly, near the region where the diffuse aurora emissions are observed, the energetic electron pitch angle distribution exhibits a butterfly-shaped pitch angle distribution, which is often associated with an electrostatic wave below the proton cyclotron frequency. This butterfly distribution is suggested to be formed by parallel acceleration of electrons through Landau resonance with the electrostatic waves. At last, I will briefly discuss a few other highlights on the interesting scientific discoveries from the Juno mission.