行星高层大气中发生的逃逸现象一直以来是行星科学的研究热点之一，而Titan在行星大气逃逸问题上具有特殊的重要性，对传统大气逃逸理论框架提出了严峻的挑战。本项目旨在研究Titan逃逸层内甲烷分子和氮分子的速度分布函数，分析其如何受外部物理条件的影响，并揭示这些成分可能的逃逸机制。研究将基于卡西尼质谱仪所获取的逃逸层密度数据，并与粒子动力学框架下的计算结果进行比较。项目所提出的研究内容既具有一定的创新性，聚焦行星科学的难点问题，同时又符合我国深空探测长远规划的需求。

Escape from planetary upper atmospheres has always been a hot topic in the community of planetary sciences. Titan plays a key role within such a context, raising critical problems to the fundamental framework of atmospheric escape. This proposal is aimed at investigating the exospheric velocity distribution functions of methane and molecular nitrogen on Titan, analyzing how they are influenced by exterior physical conditions, and revealing the potential escape mechanisms of these compositions. In this study, the exospheric density data acquired by the Cassini mass spectrometer will be compared to model results within the framework of particle kinetics. The proposed research topics are not only creative, focusing on intractable problems in planetary sciences, but also comply with the long-term plan of China's deep space exploration.