Design And Optimization Of Micro-Cathode Arc Thruster System

The working medium of Micro-Cathode Arc Thruster(μ-CAT)is a metal cathode,which does not need an additional working medium supply system.The thruster system is small in size,light in weight and simple in structure.At the same time,the voltage and current during the discharging process of the thruster are relatively small,and the power demand for the power supply is not high,which is very suitable for the propulsion system of the micro-nano satellite.In addition,the thruster uses a metal working medium with a high specific impulse,a small plume divergence angle,and a relatively low degree of pollution to the satellite surface,making μ-CAT a very promising development prospect.However,during the single pulse discharge of μ-CAT,the ablation amount of cathode material is small,the thrust of thruster is small,and the mechanism of plasma acceleration is unclear,which makes it difficult to effectively improve the propulsion performance of μ-CAT at present.In addition,because the thruster adopts non-trigger ignition mode,the ablation of conductive film is uneven,which easily leads to ignition instability and thruster failure,which limits the development and application of thruster.This paper takes μ-CAT as the research object,comprehensively uses theoretical analysis,simulation and experimental measurement and other research methods to improve the propulsion performance and working life of the thruster as the main research goal.The overall design and optimization of the thruster system are further improved.Its working performance.First,the system design of μ-CAT is carried out.Combined with theoretical analysis,the material selection and structural design of each component of the thruster are carried out;the capacitive energy storage method and the ignition circuit system are used to replace the traditional inductive energy storage and the "non-trigger ignition method";the self-generated magnetic field distribution and single particle of the thruster are developed The trajectory simulation study optimized the magnetic field configuration and completed the development of the experimental prototype.Secondly,an experimental study on the discharge characteristics and propulsion performance of the coaxial μ-CAT under vacuum conditions was carried out,and the influence of electrical parameters,geometric parameters and additional magnetic field on the discharge characteristics and propulsion performance was explored.The research results show that increasing the discharge voltage and discharge capacitance can increase the primary impulse and specific impulse of the thruster,but it will reduce the thrust power ratio of the thruster.The increase of the discharge voltage will intensify the shock of the electric parameters,thereby affecting the life of the thruster;the additional magnetic field can restrain the plume to a certain extent,but has little effect on the discharge characteristics and propulsion performance of the thruster.The thruster discharge current The generated self-induction magnetic field has no obvious effect on the acceleration of plasma.Finally,the parallel polar plate type μ-CAT was optimized and designed,using single particle and plasma simulation analysis to study the ion acceleration process under different additional magnetic field conditions,and the additional magnetic field,electrode plate configuration and The effect of the distance between the plates on its discharge characteristics and propulsion performance.The research results show that the additional magnetic field will not affect the working stability of the thruster,but it can significantly improve its propulsion performance.The gradual magnetic field whose magnetic induction intensity gradually decreases along the direction of the thruster exit has a better effect on the improvement of the propulsion performance;discharge electrode plate Both the configuration and spacing of the electrode plate will have a certain impact on the discharge waveform.Both the tongue shape and the expanded shape can improve the propulsion performance,and the latter has a better promotion effect.The increase of the electrode plate spacing is also conducive to improving the propulsion performance.