Energetic Charged Particle Observations During Juno's Close Flyby of Ganymede

On 7 June 2021, NASA's Juno mission obtained unique measurements of Ganymede's magnetosphere during a close flyby that brought the spacecraft within similar to 1,000 km of its surface. Here Jupiter Energetic particle Detector Instrument observations are presented and analyzed. The electron pitch angle distributions reveal distinct regions of Ganymede's magnetosphere that can be characterized as inbound and outbound magnetospheric boundaries, a magnetotail/wake region, and Ganymede's open field line region. Evidence for energy dependent electron pitch angle structuring is also documented both outside and within Ganymede's magnetosphere. Electron precipitation is observed and mapped to Ganymede's surface along Juno's magnetic footpoint.

Automated summary

This study presents and analyzes unique measurements of Ganymede's magnetosphere obtained by NASA's Juno mission. The study identifies distinct regions of the magnetosphere, characterizes inbound and outbound magnetospheric boundaries, a magnetotail/wake region, and Ganymede's open field line region. It also documents evidence of energy dependent electron pitch angle structuring and electron precipitation mapped to Ganymede's surface.