Fast steady-state simulation of electrospray thruster plumes using tracer particles

This paper presents a new method for steady-state simulation of an electrospray thruster exhaust plume. The method, iterative tracer particle (ITP), leverages the similarity between an electrospray thruster exhaust plume and a heavy ion beam to employ tracer particles in order to determine the charge density distribution in the steady-state plume. The solutions from ITP are validated against the commonly used particle-in-cell method for an axisymmetric simulation domain, demonstrating solution consistency (<1% error) with a factor of 30 reduction in processing time and a factor of 25 reduction in memory usage depending on the test case. This reduction in computational time and memory enables faster and efficient studies of electrospray plume dynamics and potentially enables the ability to solve the inverse problem of relating downstream experimental plume measurements to the unobservable properties of the plume at emission. A basic implementation of the ITP approach is included in the supplementary material.