LASP Magnetosphere Seminars

Abstract

Uranus’s magnetosphere presents a compelling scientific target and provides a unique opportunity to test current understanding of multiple aspects of magnetospheric dynamics. This presentation reviews a set of new results that provide new insights into the dynamics of the Uranian magnetosphere and their implications for its coupling to the planet, the satellites, and the solar wind. A fresh survey of energetic particle observations from the Low Energy Charged Particle (LECP) instrument on Voyager 2 has revealed a surprisingly localized source of energetic particles in the region between the moons Miranda and Ariel. In reviewing potential sources, the most likely conclusion was that these particles are originating from either sputtering or activity on one or both of the moons. A new simple, yet valuable and illustrative model of Uranus’ offset, tilted, and rapidly-spinning magnetic field and magnetopause was developed to investigate details of the seasonal and interplanetary magnetic field (IMF) orientation dependencies of dayside and flank reconnection along the Uranian magnetopause. The active and continuous driving of the Uranian magnetosphere observed should result in constant loading and unloading of the Uranian magnetotail, which may be further complicated and destabilized by sudden changes in the IMF orientation and solar wind conditions plus the reconfigurations from the rotation of Uranus itself. Our simple model also maps signatures of dayside and flank reconnection down to the Uranian ionosphere, as a function of planetary latitude and longitude. Uranus’s rapid rotation and unique global magnetospheric convection should be consistent with both fueling of the surprisingly intense trapped radiation environment and the very low plasma densities observed by Voyager 2. These hypotheses can be tested with further work involving more advanced models, new auroral observations, and unprecedented missions to explore the in-situ environment from orbit around Uranus.