Saturn's field-aligned current systems as observed by the Cassini mission

A long-standing question within Saturn’s magnetosphere is the source of the ubiquitous oscillations, known as planetary period oscillations (PPOs). From radio and magnetometer data it is known there are two such oscillation systems, one in the northern hemisphere and the other in the southern. In this talk, we will review analyses of azimuthal magnetic field data from the Cassini mission right up to its end in 2017 which show the presence of field-aligned currents. Using these data, several field-aligned current systems are shown to be present in Saturn’s auroral regions and their relationship with the PPOs was revealed. The implications of these results on Saturn’s periodicities, aurora, and coupling between the ionosphere and magnetosphere will be discussed.