A new approach to Saturn's periodicities

Saturn's magnetospheric periodicities are commonly thought to have a dual nature, one period originating from the southern hemisphere and a slightly different period from the northern. Both periods vary a few percent over time intervals of years and apparently merged a few months after Saturn equinox. These periodicities have not been explained. The dual‐period waveform is generally represented as the superposition of two sinusoids with nearly equal periods. However, dual‐period waves can also result from an amplitude modulation of a carrier periodicity, from frequency modulation of the carrier, from random phase jumps in the carrier, and from small, random changes in the period itself. While such simple phenomena are well known in the radio community, they can serve as possible explanations for how a single planetary period can appear as the dual (or multiple) periods observed in Saturn's magnetosphere. Candidates for modulation and randomization include the solar wind pressure and speed, the orbital periods of moons of Saturn, or even the trajectory of the Cassini orbiter itself.