资源环境科技发展态势分析平台

The morphology of electron pitch angle distributions (PADs) helps to identify dynamic processes in Saturn’s magnetosphere. Previous studies demonstrated convective transport being important for relativistic electron acceleration at L>4 in the inner magnetosphere, whereas closer to Saturn the situation is not as well established. We have investigated the PADs of relativistic electrons throughout radiation belts, using 13-year measurements from Cassini spacecraft. Our results show that at 3.57 MeV. These results suggest that convective transport continues to govern down to L=3.5. For even smaller L-shells, the independence of butterfly PAD from energy suggests that the acceleration by resonant interactions of electrons with waves likely serves as an additional key mechanism regulating the dynamics in the core region of radiation belts.