Research On Plume Pollution Effect Of Hall Thruster

Hall thruster is currently the most widely used and best-developed type of electric propulsion system.Due to its outstanding characteristics such as high specific impulse and long life,it is increasingly used in various aerospace fields.However,unlike chemical thrusters,Hall thrusters,when in orbit,will create an artificial plasma environment,in which more safety issues will be brought for the complex space environment during orbit operation.When operating in the inherently complex space environment,it will bring more safety hazards to the spacecraft.Therefore,it has great significance to studying and analyzing the physical interaction process of the interaction between the thruster plume environment and the spacecraft has a very important effect on for the development and optimization of the hall thruster.The interaction between the thruster plume and the spacecraft is mainly due to the backflow of CEX ions caused by the charge exchange collision,which causes sputtering corrosion,deposition pollution,and charging and discharging effects.The methods applied to study and analyse this issue are mainly experiment and simulation.The former includes ground test and in-orbit test.However,some features like high cost,time consuming and unable to offer comprehensive knowledge to plume environment make it still less used to research than stimulation.The relevant researches on SPT has been carried out for decades,but to create the SPT with longer operating life,the physical factors which limit its operating life must be solved.Yet,because some complex nonlinear basic physics issues are involved,the physical phenomena of SPT have not been fully understaood.The paper,by applying the hybrid Particle In Cell method,takes various collision effects between particles in the plume area into account and deals with collision model by the method of Monte Carlo Collision.Based on the SPIS software platform developed by ESA and modeled by the Hall thruster SPT100,a three-dimensional plume simulation model is established.The paper mainly focuses on the analysis of the distribution rules and generation mechanism of CEX ion in the plume;the caculations of the potential distribution on the surface of spacecraft,the CEX ion density distribution after charge exchange collision and the density distribution law of beam ion;and the explanations to the reasons of the plume pollution from the physical point of view.Based on the three-dimensional plume simulation model mentioned above,the interaction between the hollow cathode and the plume region under different vacuum back pressure and different electron temperatures of the hollow cathode was mainly calculated.The simulation results imply that when the vacuum back pressure increases,the interaction between the plume area and the surface of the spacecraft will gradually increase,and the electron temperature will decrease.With the density increasing,more CEX ions will be produced,which will intensify plume pollution.