Ionization processes in the atmosphere of Titan: from electron precipitation along magnetic field lines to high-Z cosmic rays ionization
Résumé
Knowledge of the ionization profile in the atmosphere of Titan is needed to understand its chemistry. The different ionization sources have a different impact in term of altitude of ionization, intensity, and variability. The main sources are the solar EUV-XUV flux, the electrons and protons from the magnetosphere of Saturn, and the cosmic rays. In this work, we compare the result of the modeling of these ionizations with the observations by the Cassini and Huygens probes. We show that it is possible to observe the effects of the interaction of the Kronian magnetic field with Titan in the precipitating electron flux measured by Cassini. We also show that the aerosols layers, detected in the upper atmosphere, the mesosphere, and the lower atmosphere, are correlated with the ionization layers detected by several instruments. We therefore suggest that these layers are created by ionization: from EUV-XUV and electrons in the upper atmosphere, protons in the mesosphere, and galactic cosmic rays in the main haze layer