Simulation of the neutral gas flow within an electric thruster by the kinetic Fokker-Planck method and comparison with force balance measurements

Kurzfassung

This study investigates the neutral gas flow in the DEEVA electric thruster, developed within DLR. The thruster uses electron-cyclotron-resonance (ECR) discharge and a magnetic nozzle to accelerate plasma, supporting noble and reactive gases as propellants. Simulations using the Fokker-Planck method in SPARTA were conducted for argon and xenon at different flow rates to understand asymmetries in the neutral gas plume. Results showed that the original injector design caused plume asymmetry due to pressure gradients, while a refined injector produced a symmetric plume. Experimental cold gas thrust measurements partially matched simulation results and analytical models, though deviations occurred for xenon at higher flow rates. Findings support injector optimization and provide initial conditions for plasma simulations, improving discharge modeling and thruster performance. Future work will focus on density measurements and studies with diatomic propellants.