Heliospheric Conditions at Saturn During Cassini's Ring-Grazing and Proximal Orbits
Krupp, N.; Jackman, C. M.; Roussos, E.; Krimigis, S. M.; Mitchell, D. G.; Paranicas, C.; Palmaerts, B.; Dialynas, K.; Kollmann, P.
Germany, United States, Greece, Belgium, United Kingdom
Abstract
We surveyed energetic charged particle measurements by Cassini between 2016 and the end of the mission in order to identify transients of solar energetic particles and galactic cosmic rays. Such transients offer hints about the state of the heliosphere and valuable context for interpreting space weather phenomena in Saturn's magnetosphere. The period studied includes the mission's Ring-Grazing and Proximal orbits, which due to their week-long periods are ideal for capturing short timescale dynamics in the planet's magnetosphere, including solar periodicities. We find that Saturn was exposed to corotating interaction regions for nearly all the 21 final months of Cassini and encountered just two interplanetary coronal mass ejections. Several independent studies report solar periodicities and storm-time conditions in the magnetosphere at times, which coincide with the transients that we identify here.