The plasma interaction of Saturn's moon Titan: Modelling the dynamics of the ionosphere and the emission of energetic neutral atoms

该项目的目的是通过应用混合模拟代码（动力学离子，流体电子）来分析土星最大的卫星泰坦的电离层与巨行星磁层中旋转等离子体之间的相互作用。在第一部分中，我们计划将现实的电离层化学纳入土卫六等离子体环境的现有混合模型中。到目前为止，在混合方法的框架内还不可能对土卫六的电离层进行复杂的描述，主要是由于这些代码实现的粗糙网格分辨率。我们通过最近开发的一种完全并行的空间自适应混合代码克服了这个问题。扩展后的混合代码将用于研究卡西尼号最近飞掠土卫六电离层深处时获得的等离子体和磁场数据。与土卫六磁层环境的任何其他现有模型相比，修改后的混合代码将能够同时描述由于有限的离子陀螺半径和卫星电离层中的小尺度过程而导致的大规模不对称相互作用。在第二部分中，我们将进一步扩展该代码，以开发一个自一致的模型，用于从土卫六大气中发射高能中性原子（ENAs）。基于这个模型，我们计划支持卡西尼号上的离子和中性照相机（INCA）的数据分析，提供土卫六附近全球等离子体和磁场结构的快照。

The purpose of this project is to analyze the interaction between the ionosphere of Saturn’s largest moon Titan and the corotating plasma in the giant planet’s magnetosphere by applying a hybrid simulation code (kinetic ions, fluid electrons). In the first part, we plan to incorporate realistic ionospheric chemistry into an existing hybrid model of Titan’s plasma environment. So far, a sophisticated description of Titan’s ionosphere has not been possible within the framework of the hybrid approach, mainly due to the coarse grid resolution achieved by these codes. We overcome this problem by means of a recently developed, spatially adaptive hybrid code that is fully parallelized. The expanded hybrid code will then be applied to study plasma and magnetic field data from recent Cassini flybys during which the spacecraft passed deep into Titan’s ionosphere. In contrast to any other existing model of Titan’s magnetospheric environment, the modified hybrid code will be able to simultaneously describe large-scale asymmetries of the interaction due to finite ion gyroradii and small-scale processes in the moon’s ionosphere. In the second part, we will further expand this code to develop a self-consistent model for the emission of energetic neutral atoms (ENAs) from Titan’s atmosphere. Based on this model, we plan to support the analysis of data from the Ion and Neutral Camera (INCA) aboard Cassini, providing snapshots of the global plasma and magnetic field configuration near Titan.