Variation of model-predicted reconnection voltages applied to Uranus’ dayside magnetosphere

Uranus provides a key missing piece for fundamentally understanding solar wind magnetospheric interactions due to its location in the outer solar system. Whether the viscous-like interaction overtakes global magnetic reconnection as the dominant process at the magnetopause of the outer planets remains unresolved. Here, we present theoretical predictions of dayside reconnection voltages applied to the Uranian system under different magnetospheric configurations to assess the effectiveness of global magnetic reconnection in the driving of Uranus’ magnetosphere. We find the median model-prediced dayside reconnection voltage applied to Uranus’ magnetosphere is 16.6 kV. Over just one full planetary rotation, the reconnection voltages are found to vary by tens of kV under Uranus’ magnetospheric configuration during its solstice and equinox seasons with fixed solar wind conditions. However, any fluctuations in the reconnection voltages that result from seasonal changes to the magnetospheric configuration are found to be insignificant in comparison to solar wind and diurnal magnetospheric variability. An increase from ~17 kV to ~31 kV in the modeled reconnection voltages is observed when the strength of the interplanetary magnetic field is increased corresponding to expected conditions during solar maximum. However, our results suggest that variability resulting from the planet’s diurnal rotation and changing solar wind conditions, are more important in controlling the reconnection voltages than seasonal dependencies.