Research On The Application Of Plasma In Hall Thrusters System

With the continuous development of space technology,higher requirements are put forward for propulsion system.Hall thruster is widely used in on-orbit operation,attitude maintenance and deep space exploration of various military and commercial satellites due to its advantages of small volume,high thrust density and high specific impulse.In recent years,the improvement of discharge efficiency in Hall thruster has become one of the hot issues in research.The purpose of this paper is to use the Particle in cell plus Monte Carlo collision(PIC-MCC)method to simulate the discharge characteristics of Hall thruster,further optimize the input parameters,improve the propulsion performance and improve the propulsion efficiency by analyzing the calculation results,and provide some theoretical guidance for independent research and development of high-performance Hall thrusters in China.The Particle in cell method and fluid simulation method are the two most commonly used methods in the numerical simulation of Hall thruster.However,because the particle simulation method is more intuitive than the fluid simulation method and truly reduces the microscopic state inside the plasma,this paper adopts the Particle in cell plus Monte Carlo collision(PIC-MCC)method The physical model of Hall thruster is established based on particle simulation method,and the computing platform of particle simulation(HD-HER)is independently developed by using C++ language.The distribution of plasma in the channel of Hall thruster is an important embodiment of the discharge characteristics of Hall thruster system,and it is essential to analyze the electromagnetic field inside Hall thruster in order to simulate the transport properties of various particles in the discharge process.Firstly,based on Maxwell’s equations,the distribution of electromagnetic field in the channel is obtained by finite difference method.Then,by tracking the movement of each particle in the channel,the dynamic distribution of various particles and electromagnetic field in the Hall thruster is obtained,and the ion velocity,thrust,specific impulse and other parameters in the Hall thruster are calculated,and the discharge characteristics of the thruster are analyzed in detail.Secondly,in order to study the influence of propellant on the propulsion system,the discharge of Hall thruster with different working fluids at various mass flows was obtained through simulation calculation by changing the different mass flows of xenon and argon propellants.The simulation results show that the distribution of electromagnetic field in Hall thruster is along the axial direction,which increases first and then decreases,and reaches the maximum near the channel mouth.With the increase of time step,most electrons from the cathode will be bound here by the strong magnetic field at the channel mouth,and then collide with the neutral gas from the anode to produce ions.Ions move inside the channel,forming a highdensity area near the channel mouth,and finally accelerating ejection under the action of axial electric field,thus providing thrust to the spacecraft.When the same working medium has different mass flows,the time for the discharge process to reach steady state is different,and the density and velocity distribution of ions are also significantly different.With the increase of propellant mass flow,the plasma density and thrust in the propulsion system will increase accordingly.Under the same conditions,the discharge efficiency of xenon working medium is greater than that of argon working medium.