Hi Kellie!

At least auroras have been spotted on Uranus and Neptune! http://news.nationalgeogr...cience-space-hubble/ and http://www.windows2univer...sphere/N_aurora.html

The planets in our solar system have different magnetospheres and thus their dynamics are different. For some planets their moons (for example volcanic moon Io of Jupiter) and ring systems may also affect the plasma population in the magnetosphere and its dynamics. So it is not straightforward to compare the activity that happens in them. Solar wind influence is also different as the solar wind magnetic field and density gets weaker when the distance from the Sun increases.

Emilia