Energetic Electron Imaging of Ganymede's Magnetic Field by the Juno
Spacecraft's Advanced Stellar Compass
Abstract
The micro Advanced Stellar Compass (µASC), an attitude reference for the
Juno Magnetic Field investigation, also continuously monitors high
energy particle fluxes in Jupiter’s magnetosphere. The µASC camera head
unit (CHU) shielding is sufficient to stop electrons with energy
<15MeV. By recording the number of particles that penetrate
µASC CHU shielding and deposit energy in the CCD sensor, the µASC
functions as an energetic particle sensor with a detection threshold
well above that of the Juno Energetic Particle Detector Instrument
(JEDI) flown for that purpose. Radiation data gathered by the µASC is
used to monitor the radiation environment of Jupiter and mapping of the
trapped high energy particles. Comparison of the particle population
around Jupiter with individual perijove particle observations reveals
disturbances when Juno is traversing Ganymede’s M-shell. We present
highly energetic electrons interaction with Ganymede’s magnetic field,
magnitude and extend of the particle depletion associated with the
Ganymede interaction.