Electron Trajectory Simulation in compact Hexapole ECR ion thruster

Abstract

Magnetic mirrors are used to construct electron traps in compact hexapole ECR thrusters. Hexapole magnets and annular magnets are used to build a compact ECR ion thruster. Two annular N52 neodymium magnets are used to construct the structure of the magnetic mirror of the axial. The discharge chamber outlet will form a magnetic nozzle to eject plasma to obtain thrust. On this basis, a hexapole magnet is added to restrict the movement of electrons in the radial direction. It will construct a high-density electronic cyclotron resonance zone in a space that will cause the passing gas molecules to be bombarded by electrons and ionize into ions. The simulation results show that in the thruster axial direction and radial direction, the coverage of the ECR resonance surface is 100 % and 94 %, respectively. The low-energy electrons should be confined in the thruster to ionize the propellant, while the high-energy electrons can escape the magnetic mirror to create the jet. The simulation of the trajectory of electrons in the thruster confirms that the thruster has a good confinement effect on low-energy electrons. This will make the propellant gas have a higher chance of being bombarded by electrons and ionized to form ions when passing through the discharge chamber. High-energy electrons are less affected by the magnetic field, not constrained by the magnetic trap. They can accelerate through the magnetic nozzle and leave the thruster to form an electron jet. This article shows the compact hexapole ECR ion thruster design parameters and simulation results.