Coupled molecular dynamics — One-dimensional PIC simulations of ionic liquid electrospray thrusters

Molecular dynamics (MD) simulations are performed to model an electrospray thruster for the ionic liquid (IL) EMIM-BF₄ using a coarse-grained (CG) potential. A one-dimensional electric field was computed by the use of a Particle-In-Cell (PIC) solver and coupled to the MD program. The electrical extrusion of the IL was studied for different electric field strengths and mass flow rates. The MD simulations provide the first insight into the atomistic modeling of a capillary-tip-extractor system, the basic elements of an electrospray thruster. Current distributions and anion and cation behavior were characterized and compare reasonably well with measurements. Moreover, the role of inhomogeneities in the electric field as well as that of the IL space-charge most likely will improve agreement between modeling and experiment.