Influence Of Low Frequency Oscillation On The Performance Of Plasma Beam Focalization Hall Effect Thruster

Hall thruster (HET) has been widely used as the satellites propulsion and in the deep space exploration missions since its advantages such as the high specific impulse and high efficiency. The low frequency oscillation is an inevitable phenomenon in the working hall thruster, it is closely associated with the ionization and acceleration processes, and has a serious impact on the performance of the hall thruster. During the study on the low frequency oscillation of hall thrusters, the means for regulating it is changing the magnetic field strength. At present, there has no comprehensive summary about the relation between oscillation and the performance of the hall thruster.The magnetic field strength is one of the discharge parameters of hall thruster, and the change of it will certainly influence the performance of the hall thruster .Therefore, we are not sure about the reason of the change of performance is whether the change of magnetic or the change of the low frequency oscillation during the research of oscillation on the performance in hall thruster when we obtain the oscillation by changing magnetic field strength. In the thesis, we obtain different oscillations by regulating the circuit parameters on the basis of fixed discharge parameters .Additionally, in this paper we also give a deep study on the mechanism of the relationship between oscillation and performance from the point of view of experiment and numerical simulation on the basis of different low frequency oscillation obtained by changing circuit parameters.Firstly, starting from the outer circuit of HET and the description of low frequency oscillation, the change trends of the low frequency oscillation parameters(the oscillating amplitude, the phase difference and the frequency) with the varying of circuit parameters such as the resistance R, inductance L and capacitance C .And describe the physical processes of the current oscillation and the voltage oscillation on the point of view of the ionization process and the acceleration process in hall thruster channel.Secondly, through experiments and numerical simulations, the mechanisms of the current oscillation on the discharge current and the voltage oscillation on the thrust are studied .The reason of the discharge current grow with the current oscillation and the reason of the current utilization decrease with the current oscillation are given on the basis of the composition of the discharge current during the research of the relationship between the discharge current and the current oscillation. And the dominant factor of the thrust during the change of voltage oscillation is given from the view of the expression of it in a hall thruster .Following, the mechanism is obtained by a series of orthogonal experiments and numerical simulations.Finally, from the experimental point of view, based on the hall thruster performance architecture, the relationship of the utilizations and the outer circuit parameters are summarized. At last, the conclusion that the matching of outer circuit parameters play a very important part in the optimizing of the performance of hall thruster.