Asymmetries in Saturn's radiation belts

作者：Paranicas C^*; Mitchell D G; Krimigis S M; Carbary J F; Brandt P C; Turner F S; Roussos E; Krupp N; Kivelson M G; Khurana K K; Cooper J F; Armstrong T P; Burton M

来源：Journal of Geophysical Research, 2010, 115: A07216.

DOI：10.1029/2009JA014971

We present both energetic proton and electron data from the main radiation belts of Saturn. When organized by L shell and equatorial pitch angle, data from Cassini's Magnetospheric Imaging Instrument reveal proton radiation belts that are highly symmetric in local time. The energetic electron radiation belts are asymmetric in two principal ways. Using data from two close passes of the planet, we find for energies near a few MeV, electron intensity levels are different between noon and midnight. Furthermore, when Cassini was inbound to Saturn, electron fluxes dropped precipitously before the spacecraft reached the main rings. Outbound, electron fluxes returned to high levels when the spacecraft moved outward of the main rings. In this paper, we suggest that electron flux level asymmetries are due in part to the presence of local time stationary particles in Saturn's inner magnetosphere. We also consider possible mechanisms to account the drop off of electrons near the ring edge on the dayside.

• 出版日期2010-7-17