Cassini/MIMI Observations on the Dungey Cycle Reconnection and Kelvin-Helmholtz Instability in Saturn's Magnetosphere

Abstract

A new composite analysis of ∼13 years of Cassini's Charge Energy Mass Spectrometer measurements, presented by Allen et al. (2018, https://doi.org/10.1029/2018JA025262), suggests that the asymmetrically distributed suprathermal He⁺⁺ in Saturn's magnetosphere is due to Dungey cycle related reconnection and Kelvin-Helmholtz instabilities that provide paths to the solar wind plasma to reach distances even deep in the inner magnetosphere and accumulate in the ring current region, together with the internally sourced plasma. The results provide a significant addition to the ongoing discussions concerning the contribution of the solar wind input to the dynamics of an otherwise rotationally driven system, such as Saturn's magnetosphere.