Study On Discharge Characteristic Of Ignition Period In High Power Hall Thruster

Along with the upsurge of interstellar exploration and the rise of the corresponding concept of all-electric-push satellite platform.The demand for high-power and high-thrust thrusters is increasing.After analysis and demonstration,the high-power Hall thruster is considered to be the most suitable space power device for this series of missions,which attracts the attention of many researchers.In view of the above situation,this course mainly focuses on the research of high-power Hall thruster,focusing on the first and most important step to ensure the stable operation of high-power Hall thruster,namely ignition process,which is of great significance to enhance the stable operation of the thruster.The main work of this paper is as follows.Firstly,aiming at the ignition process of high power Hall thruster,the PIC-MCC method is used to establish the ignition model.The model results are in good agreement with the experimental results of kW class thruster.On this basis,the distribution of ion density,potential and atomic density parameters during ignition is further analyzed.In addition,the calculation speed of high power thruster is too slow.By increasing the number of real atoms represented by a single simulated atom and the size of the simulated grid,the calculation speed is effectively improved and verified in a KW Hall thruster.The results show that the accuracy of the accelerated system is within acceptable range.Secondly,the ignition start-up conditions of high-power Hall thruster are studied by using the ignition model.It is considered that the low discharge voltage leads to the failure of ignition when electrons fail to enter the discharge channel properly.Under the condition that ignition can be successful,the influence of discharge voltage,mass flow rate and magnetic field intensity on ignition start-up is analyzed,and the slope of current rising section represents the difficulty of ignition.The slope can be used as the boundary of ignition success.Finally,it is found that the cathode placed outside the thruster is easier to ignite successfully.Thirdly,the influence of ignition parameters of high power Hall thruster on ignition shock peak value is studied.The ignition process is measured by changing discharge voltage,mass flow rate,magnetic field intensity and cathode position.The results show that discharge voltage and mass flow can increase ignition shock;magnetic field intensity has little effect on ignition shock;the point of external cathode is relative to that of internal cathode.The fire impact is larger and there is a certain ignition trailing section.The ignition impact of the external cathode outside the magnetic interface is larger than that of the external cathode inside the magnetic interface.Finally,the conversion process of high power Hall thruster from ignition to steady state is studied.Firstly,it is determined by simulation that the discharge power can be increased by adjusting mass flow and discharge voltage separately.Furthermore,the ignition conversion process is measured by experiments.The results show that the method of adjusting excitation current and discharge voltage first is better than that of adjusting discharge voltage and excitation current first.The cathode placement mode has less influence on the conversion process.In the process of adjusting to higher power,it is more necessary to adjust excitation current first.