Speaker: Dr. Qianli Ma
Affiliation: Boston University / UCLA
Date: Friday, October 16, 2026
Time: 3:30 PM
Zoom/Meeting Link: https://ucla.zoom.us/j/97178405473?pwd=WMx7ClxaSw38JatXhzPshjC5G0O1Um.1
Abstract
Planetary radiation belts contain high fluxes of relativistic electrons trapped by the closed magnetic field lines. Radial diffusion and wave-particle interactions are the key processes governing electron acceleration and transport. At Earth, the energetic electron fluxes can increase by several orders of magnitude following geomagnetic storms driven by solar wind structures. In contrast, Jupiter’s inner magnetosphere is predominantly driven by internal sources owing to its strong magnetic field and rapid rotation. Despite these differences, recent Juno measurements in the region from Io to Ganymede’s orbit suggest a similar plasma environment conducive to wave-particle interactions to that in Earth’s outer radiation belt. Energetic electron injections and whistler-mode chorus and hiss waves, which are critical for the radiation belt electron variability at Earth, are also prevalent at Jupiter at 6 < M < 15. The modeling of electron scattering by the waves suggest efficient electron precipitation from Jupiter’s radiation belt to the upper atmosphere. The diffuse electron precipitation has been validated by both direct precipitation measurements at high latitudes and patchy auroras observed by Juno’s Ultraviolet Spectrograph. The radiation belt simulation also suggests chorus waves may accelerate electrons at multi-MeV energies in Jupiter’s radiation belts. In addition, the Galilean moons Io, Europa and Ganymede reside within the region of active wave-particle interactions. These moons absorb relativistic electrons, producing localized flux dropouts, and amplify plasma waves, enhancing electron scattering. Thus, moon–plasma interactions can substantially modify relativistic electron distributions in Jupiter’s radiation belt.