Joe Kinrade

Saturn is engulfed in a cloud of neutral gas that originates from ice fissures on the surface of Enceladus. Some particles collide and exchange charge, separating electrons and ions which are guided by Saturn’s magnetic field. In this way, Saturn’s rotating magnetosphere is loaded with mass, which eventually must be lost into space via ejections of plasma that stretch magnetic field lines to breaking point.

Some charged particles in the outer magnetosphere do not escape, but are fired back towards Saturn with field lines as they snap back into place. These energetic ions collide with neutrals, creating energetic neutral atoms (ENA) that were detectable using the INCA camera onboard Cassini. Pictures of Saturn’s magnetosphere from INCA reveal dynamic regions of plasma flow, important for understanding the entire system.

We present an analysis of the INCA image set obtained throughout Cassini’s mission. We’ve processed ~670,000 images to characterise Saturn’s average ENA morphology. Rings of ENAs are located at distances between 7-10 Rs, the point of peak interaction between the energetic ions and the neutral cloud. We also find ENA variation with Saturn’s rotation period, associated with current systems that modulate the thickness of the plasmasheet every ~10 hours.