On the 1-hour periodicities in the Saturnian system

The exploration of the magnetospheres of magnetized planets has revealed periodic phenomena with a large variety of periods. In Saturn's magnetosphere, oscillations with a period of about one hour are commonly identified in charged particle fluxes, in the magnetic field, in plasma waves and in the brightness of localized auroral structures. We will present a review of these 1-hour oscillations using multi-instrument observations acquired during the 13 years of the Cassini mission. We will discuss possible triggers in light of the Cassini observations of the 1-hour periodicities. The presence of 1-hour quasi-periodic electrons in the close vicinity of the magnetopause supports the involvement of magnetopause processes, such as magnetic reconnection and Kelvin-Helmholtz instabilities. Pulsed electrons are also encountered much deeper in the magnetosphere and may originate from reconnection in the magnetodisk, on both the day and night sides of the magnetosphere. Moreover, similar mechanisms might take place also in the magnetosphere of Jupiter, leading to the observed periodic phenomena.