Predictions of Auroral Electron Precipitation and Joule Heating at Uranus

Abstract

The precipitation of electrons and Joule heating are key processes through which energy is transferred from Uranus' magnetosphere to its upper atmosphere. These processes drive atmospheric ionization, thermospheric heating, and auroral emission at Uranus. Here we scale measurements at Earth, Saturn, and Jupiter, with relevant Voyager 2 observations to estimate the properties of magnetospheric energy input at Uranus. We find that the acceleration of electrons between the magnetosphere and thermosphere is predicted to be Earth-like, but with significantly lower overall energy flux and field aligned currents due to Uranus' sparser magnetosphere. In addition, we estimate that the height-integrated Joule heating rates at Uranus could reach ∼1 mW/m², levels that would produce significant thermospheric heating.