Proton Equatorial Pitch Angle Distributions in Jupiter's Inner Magnetosphere

• Published in: Geophysical research letters 2023-06, Vol.50 (11), p.n/a
• Main Authors: Sarkango, Y., Szalay, J. R., Poppe, A. R., Nénon, Q., Kollmann, P., Clark, G., McComas, D. J.
• Format: Article
• Language: English
• Subjects: Adiabatic; Adiabatic flow; Astrophysics; Charge exchange; Charged particles; Earth Sciences; Energetic particles; Europa; Galileo spacecraft; Geophysics; Instruments; Juno; Jupiter; Jupiter magnetic field; Jupiter probes; Jupiter's magnetosphere; Magnetic field; neutral torus; Pitch (inclination); pitch angle distribution; Planetary magnetic fields; Planetary magnetospheres; Protons; Sciences of the Universe; Spacecraft
• ISSN: 0094-8276; 1944-8007
• DOI: 10.1029/2023GL104374

We use data from the plasma and energetic particle instruments on the Juno spacecraft, JADE and JEDI, to study the equatorial pitch angle distributions of energetic protons within Jupiter's inner magnetosphere during Juno's prime mission from 2016 to 2021. Averaging over all observations made by Juno within M‐shell bins between M = 6 and M = 30, we find protons at energies between 10 and 50 keV are predominantly field‐aligned at all M‐shells. In contrast, those at energies above 200 keV transition from being predominantly field‐aligned at M = 20 to having pancake‐like distributions at M 200 keV protons show evidence of adiabatic acceleration during inward radial transport Observed proton distributions could result from charge‐exchange with neutrals or conservation of adiabatic invariants during transport