Solving the Mystery of the Electron Radiation Belt at Uranus: Leveraging Knowledge of Earth's Radiation Belts in a Re-Examination of Voyager 2 Observations

Abstract

Voyager 2 provided the only direct measurement of the radiation environment at Uranus and established the well-accepted characterization of a system with a weaker ion radiation belt and surprisingly intense electron radiation belt. Recent re-analysis of the flyby, however, suggests that these observations were not taken during normal solar wind conditions, and instead occurred while a large solar wind transient, a corotating interaction region, was passing over the system. With this context, this study compares the Voyager 2 observations to a similar event observed at Earth. This comparative approach, along with an expanded contextual interpretation of the Voyager 2 flyby, suggests that solar wind-magnetospheric interactions at Uranus may have driven enhanced lower band chorus wave emissions capable of accelerating electrons to relativistic energies. This motivates new, more expansive questions to be explored at Uranus and highlights the need for a Uranus orbiter mission.