Magnetospheric Drift Resonance Effects on Local Time Asymmetry, Injection Events, and Moon Interactions for Saturn as Compared to Earth
Publication date: 28 May 2005
Authors: Cooper, J.F.
Journal: AGU, Spring Meeting 2005, abstract #SM11A-03
The magnetospheres of Earth and Saturn have similarities in terms of the highest energy radiation belt components from Cosmic Ray Albedo Neutron Decay (CRAND) but have otherwise been expected to differ on the role of charged particle convection driven by solar wind interactions with these magnetospheres. Saturn's inner and middle magnetosphere has been assumed to be dominated by corotation with little direct penetration by solar wind and magnetotail plasma. Since Saturn's planetary magnetic field characterized by the Z3 model is axisymmetric, although slightly offset northward from the ring plane, it has been difficult to understand previous Pioneer and Voyager measurements of local time asymmetry in energetic particle populations, including just outside the main rings as found by Pioneer 11. Small scale features (microsignatures) of charged particle absorption by Saturn moons and possible 'ghost' clouds of co-orbiting debris show no consistent patterns in the context of symmetric models for longitudinal drift shells. Since the 100-MeV CRAND proton drift shells are highly symmetric, it is apparent that lower energy electrons and ions showing substantial local time asymmetry are influenced by forces other than simple corotation. Cassini Huygens neutral atom observations show clear evidence of substorm injections reaching into the middle magnetosphere of Saturn preferentially on the nightside.