LASP Magnetosphere Seminars

Abstract

The Voyager 2 flyby of Uranus in 1986 revealed an unusually oblique and off-centered magnetic field. This single in situ measurement has been the basis of our interpretation of Uranus’ magnetosphere as the canonical extreme magnetosphere of the solar system; with inexplicably intense electron radiation belts and a severely plasma-depleted magnetosphere. However, the role of external forcing by the solar wind has rarely been considered in explaining these observations. In this talk, we will revisit the Voyager 2 dataset to see that Voyager 2 observed Uranus’ magnetosphere in an anomalous, compressed state that is estimated to be present less than 5% of the time. If the spacecraft had arrived only a few days earlier, the upstream solar wind dynamic pressure would have been ~20 times lower, resulting in a dramatically different magnetospheric configuration. Such a compression of the magnetosphere could increase energetic electron fluxes within the radiation belts and empty the magnetosphere of its plasma temporarily. Therefore, the interpretation of Uranus’ magnetosphere as being extreme may simply be a product from a flyby which occurred under extreme upstream solar wind conditions. I will also present ongoing modelling efforts that try to understand the role of magnetic reconnection at Uranus’ magnetosphere including the reconnection voltages at the magnetopause during Voyager 2’s approach to the planet. Finally, we will conclude by looking towards what an orbital tour of the magnetosphere could look like by a potential Uranian flagship mission in the future.