土星磁层是土星系统与太阳风耦合的重要区域，也是当前国际行星探测的热点研究对象。与地球磁层相比，土星的磁层环境相对复杂，并且磁层整体随行星快速旋转（约10.5小时）。此外，土卫二等离子体内源显著影响土星磁层结构，提供了比太阳风更加显著重要的粒子来源。复杂的磁层系统使得土星磁层空间既存在与地球类似的太阳风驱动的Dungey循环过程，也存在行星自旋驱动磁盘Vasyliunas循环过程。重联锋面是行星磁层中传输能量和物质的重要通道，在磁层动力学过程中起着关键的作用。目前，人们对土星磁层系统能量和物质循环图像的认识不够全面，进行系统的观测分析是十分必要的。本项目拟利用近十余年Cassini飞船在土星附近的观测数据，聚焦于土星重联锋面的磁层动力学效应，系统分析土星磁层粒子加速和物质循环过程。本项目将同时借助比较行星学研究手段来深入理解和完善土星磁层中物质和能量相互耦合、循环的物理图像。

Saturnian magnetosphere is formed by the interaction between solar wind and Saturn system, and has been extensively investigated over the past decades. Comparing to Earth's magnetosphere, the Saturnian magnetosphere environment is relatively complex. Saturn rotates rapidly (about 10.5 hours) and inner plasma source dramatically affects the configuration of Saturnian magnetosphere. Both ‘Dungey cycle’ and ‘Vasyliunas cycle’ could occur in Saturnian magnetosphere. It has been suggested that the reconnection fronts could significantly transport energy and plasma and play a key role in the processes of magnetosphere dynamics. To date, the picture of energy and plasma circulation on Saturnian magnetosphere remain unclear. It is necessary to carry out a systematic observational study on the contribution of reconnection fronts during magnetosphere dynamics. Using Cassini observations, we will systematically investigate the characteristics of reconnection fronts on Saturnian magnetosphere and its relation to magnetospheric particle acceleration process, as well as auroral phenomena. To compare reconnection fronts on Saturnian with those on Earth and Jovian magnetosphere, we expect to advance the picture of the coupling and circulation of plasma and energy in Saturn's magnetosphere.