Clues on Ionospheric Electrodynamics From IR Aurora at Jupiter and Saturn

Ionospheric flows within the upper atmospheres of the gas giants provide a valuable tool with which to understand the currents flowing through the ionospheres of these planets, as well as the magnetospheric origin of these currents. These flows are measured using high-resolution long-slit spectroscopy from ground-based telescopes, producing both intensity and velocity profiles that allow us to understand the flows and see how they are associated with the aurorae. Thus, it is possible to compare and contrast both morphology and flow speeds of H-3(+) in the ionospheres of Jupiter and Saturn, revealing a number of significant similarities suggesting comparable origins for ionospheric features created by currents that are associated with both internal circuits and the influence of the solar wind. There remains much controversy about the way the solar wind affects these planets, particularly at Jupiter. Only with more detailed observations will this controversy be resolved.