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Abstract

Uranus’ strongly asymmetric internal magnetic field coupled with its unusually large obliquity results in a highly dynamic magnetosphere that undergoes significant diurnal and seasonal variations. Data from the single flyby by the Voyager-2 spacecraft along with limited telescopic observations of its atmosphere and aurora provided only a glimpse of how such complex magnetospheric reconfiguration takes place. In this work, we have applied the BATSRUS magnetohydrodynamics (MHD) code to Uranus to simulate how the global configuration of its magnetosphere varies through rotation cycles and between different seasons. The global MHD simulation incorporates a realistic internal field model and adopts a high-resolution grid that allows for resolving the fine structure of key magnetospheric boundaries. Simulations for near-solstice and for equinox conditions have been performed to compare and contrast the solar wind interaction with Uranus’ magnetosphere at different seasons. Comparison of the simulation results with the Voyager data indicates that our MHD model reproduces the global structure of Uranus’ magnetosphere with high fidelity. In particular, the model accounts for the unusual structure and temporal variation of the tail plasma sheet that was sampled by the Voyager spacecraft. We will show how Uranus’ magnetosphere periodically changes its configuration following the planetary rotation and discuss the morphology and physical origin of the large-scale current systems extracted from our simulations and their implications for understanding available auroral observations.