Dandouras Iannis, Garnier Philippe, Mitchell Donald G, Roelof Edmond C, Brandt Pontus C, Krupp Norbert, Krimigis Stamatios M
Centre d'Etude Spatiale des Rayonnements, Université de Toulouse, 31028 Toulouse, France CNRS, UMR 5187, 31028 Toulouse, France.
Philos Trans A Math Phys Eng Sci. 2009 Feb 28;367(1889):743-52. doi: 10.1098/rsta.2008.0249.
Titan's nitrogen-rich atmosphere is directly bombarded by energetic ions, due to its lack of a significant intrinsic magnetic field. Singly charged energetic ions from Saturn's magnetosphere undergo charge-exchange collisions with neutral atoms in Titan's upper atmosphere, or exosphere, being transformed into energetic neutral atoms (ENAs). The ion and neutral camera, one of the three sensors that comprise the magnetosphere imaging instrument (MIMI) on the Cassini/Huygens mission to Saturn and Titan, images these ENAs like photons, and measures their fluxes and energies. These remote-sensing measurements, combined with the in situ measurements performed in the upper thermosphere and in the exosphere by the ion and neutral mass spectrometer instrument, provide a powerful diagnostic of Titan's exosphere and its interaction with the Kronian magnetosphere. These observations are analysed and some of the exospheric features they reveal are modelled.
由于土卫六缺乏显著的固有磁场，其富含氮的大气层受到高能离子的直接轰击。来自土星磁层的单电荷高能离子与土卫六高层大气（即外逸层）中的中性原子发生电荷交换碰撞，转化为高能中性原子（ENA）。离子与中性相机是卡西尼/惠更斯号土星和土卫六探测任务中磁层成像仪器（MIMI）的三个传感器之一，它像拍摄光子一样对这些ENA成像，并测量它们的通量和能量。这些遥感测量结果，与离子和中性质谱仪仪器在上热层和外逸层进行的原位测量相结合，为土卫六的外逸层及其与土星磁层的相互作用提供了强有力的诊断依据。对这些观测结果进行了分析，并对它们揭示的一些外逸层特征进行了建模。
