Conjugate ionospheric flows on Uranus

Consideration of the pointing direction and rotation period of the spin of Uranus suggests that a novel kind of day-to-night ionospheric flow system may exist there. For equatorial distances r<r_c (≈2.74r _p), the conjugate ionospheric flow from the dayside hemisphere to the nightside hemisphere could become supersonic as it crosses the equator and a shock forms at the termination point; for r>r_c, smooth transition at the contact point between the ionospheric flow from the dayside hemisphere and the nightside atmosphere is possible. The rotational effect of Uranus also limits the inner extension of the thermal plasma disk generated from energetic particle sputtering of the ring-particles and satellites. The combined effect of the dynamic transport of the ionospheric plasma and the injection of ring plasma into the upper atmosphere could provide interesting results concerning the ionosphere of Uranus, which is to be explored by the Voyager 2 spacecraft in 1986.