An empirical model for the plasma environment along Titan's orbit based on Cassini plasma observations

Abstract Prior to Cassini's arrival at Saturn, the nitrogen‐rich dense atmosphere of Titan was considered as a significant, if not dominant, source of heavy ions in Saturn's magnetosphere. While nitrogen was detected in Saturn's magnetosphere based on Cassini observations, Enceladus instead of Titan appears to be the primary source. However, it is difficult to imagine that Titan's dense atmosphere is not a source of nitrogen. In this paper, we apply the Rymer et al.'s (2009) Titan plasma environment categorization model to the plasma environment along Titan's orbit when Titan is not present. We next categorize the Titan encounters that occurred since Rymer et al. (2009). We also produce an empirical model for applying the probabilistic occurrence of each plasma environment as a function of Saturn local time (SLT). Finally, we summarized the electron energy spectra in order to allow one to calculate more accurate electron‐impact interaction rates for each plasma environment category. The combination of this full categorization versus SLT and empirical model for the electron spectrum is critical for understanding the magnetospheric plasma and will allow for more accurate modeling of the Titan plasma torus.