Ionization processes in the atmosphere of Titan II. Electron precipitation along magnetic field lines

摘要: Context. The Cassini probe regularly passes the vicinity of Titan, providing new insights into particle precipitation by use its electron and ion spectrometers. A discrepancy between models observations fluxes has been found. This was suspected to be caused geometry magnetic field. Aims. In this article, we compute impact ionization in nightside ionosphere assuming non-trivial for field lines. Methods. We TransTitan model, modified take account line nightside, compare these results with flux measurements during T5 fly-by Cassini. several geometries, including one produced hybrid simulations. Results. lines implies a longer path inside atmosphere Titan. are therefore considerably compared vertical hypothesis. At an altitude 1200 km, can divided up ten times resulting from simulation. Thanks more accurate lines, model reproduces experiment well without any further adjustment precipitated measured flux. Conclusions. Several hypothesis had suggested explain discrepancies different observation Our approach shows that most probable explanation is geometry. work computation production Titan needs consideration both input fluxes. Based on considerations, our conditions future fly-by, could used experiments.