Enhanced Precipitation of Energetic Protons Due to Uranus' Asymmetric Magnetic Field

Abstract Uranus remains one of the most unexplored planets in our solar system, featuring a distinctive magnetic field structure first observed by NASA's Voyager 2 mission almost 40 years ago. Uranus is particularly notable for its pronounced magnetic field asymmetry, a characteristic unique to the icy giants. Here we show that, in the region where Voyager 2 did not pass (), the asymmetric magnetic field can distort the trajectories of high energy protons within Uranus' radiation belts such that the particles hit the planet when they otherwise would not have (in a traditional dipole field). This implies that radiation belt protons which start with pitch angles well outside their respective loss cones can drift into a region where the loss cone is much bigger and then precipitate. This occurs preferentially in the magnetic north pole due to its significantly weaker surface field strength.