Design And Experimental Study Of Inertial Electrostatic Confinement Thruster

Inertial Electrostatic Confinement Thruster(IECT)is a new type of electrostatic thruster.It mainly utilizes the inertial electrostatic confinement ionization mechanism and particle confinement mechanism to highly ionize the working gas in the ionization chamber.The plasma is ejected from the ionization chamber to generate thrust by changing the grid structure.When the pressure is about 10 Pa,the plasma density of the inertial electrostatic confinement thruster can reach a magnitude of 1015 to 1018 m-3.In addition,the thruster has the advantages of simple structure,anti-ablative,non-hollow cathode,long life,etc.There are broad application prospects in areas such as space advancement and deep space exploration.This article summarizes the research work of inertial electrostatic confined thrusters by foreign research institutes,and analyzes its working principle by using spherical double layer theory.Its principles mainly include the low-voltage discharge mechanism of IECT and the IECT beam extraction mechanism.The particle motion trajectory model,ion distribution model and potential model describing the internal physical properties of the inertial electrostatic confinement thruster are introduced.A 2-D axisymmetric model of the thruster ionization chamber was established using COMSOL simulation software.Numerical parameters such as electron number density,reaction rate,and collision power loss generated by the thruster discharge were simulated.The plasma parameters of different structural thrusters were simulated separately and compared.The simulation results show that the IECT with different structures work in different pressure ranges,and the thruster size can be flexibly designed for different background pressure working conditions.In addition,when designing the IECT prototype,the grid density of the thruster could be appropriately increased under the necessary conditions for ensuring the geometrical transmittance of the cathode,and the number density of the ejected electrons can be increased and the plume divergence angle can be reduced.The discharge conditions of the same thruster under different working conditions are simulated.The simulation results show that the plasma density emitted by the thruster increases with the increment of background pressure and cathode voltage.A cylindrical inertial electrostatic confinement thruster prototype was designed based on the simulation results.The discharge performance of the thruster prototype was tested by the self-built experimental system.The test results show that the thruster designed in this paper can work stably under the conditions of pressure 5~20Pa and cathode voltage-500~-1500 V.Record and plot the volt-ampere characteristics of the thruster at a background pressure of 11 Pa.The conditions such as background pressure,cathode voltage,and mass gas flow rate were changed to observe the thruster discharge phenomenon and the Langmuir probe system was used to diagnose the plume of the thruster.The experimental results show that the plasma shape in the thruster changes greatly while increasing the background pressure or the cathode voltage,and the plasma density in the plume increases.Increasing the mass flow rate of the working gas,the shape of the plume did not change significantly,while the plasma density in the plume slightly increased.