Several random examples for the stepwise trajectories of incident CH ions within Titan’s upper atmosphere, all starting at an energy of 50 keV under normal incidence. Three different cases are indicated in the upper panel, including one ion thermalized below the lower boundary (panel A), another ion escaping from the upper boundary (panel B), and a third ion with energy falling below the local escape energy within the simulation box (panel C). The portion of each ion trajectory between two consecutive collisions is displayed as the projection to the local plane formed by the vertical direction and the direction of ion velocity with the x-axis aligned with the projected ion trajectory on the horizontal plane. Zoomed-in images of the portions of ion trajectories within the dashed boxes are shown in the lower panels.