“…We demonstrate the use of an appropriate forward model simulating the expected response of an electrostatic analyzer in the presence of plasma of heavy, negative ions. The development of forward models is not only useful in dataanalyses (e.g., Nicolaou et al, 2014b;Nicolaou et al, 2021;Wilson et al, 2008;Wilson et al, 2017, Elliott et al, 2016, but also in testing the performance of the instrument in a range of expected conditions (Kessel et al, 1989;Cara et al, 2017;Nicolaou et al, 2014c;Nicolaou et al, 2014b;Nicolaou et al, 2020a;Nicolaou et al, 2020b;Nicolaou and Livadiotis, 2016). In this study we focus on the ability to resolve key species for plasma science in the vicinity of Enceladus and Titan.…”