Effects of focusing and diverging magnetic field topology on hall thruster channel wall erosion

In order to study the effects of magnetic field on hall thruster channel wall erosion, contourgraph is utilized to measure the erosion status of inner and outer wall after Hall thruster works for 30 h. The wall erosion process of thruster is compared under focusing magnetic field and diverging magnetic field conditions. The method and intensity of improving wall erosion by focusing magnetic field are analyzed, and the mechanical analysis is performed. The experimental results show that after 30 h experiment, compared with diverging magnetic field, the erosion depth of interior ceramic wall is reduced by 33% under focusing magnetic field conditions, and the erosion depth of exterior ceramic wall is reduced by 18.6%. The theoretical analysis shows that when the plume divergence half-angle is below 30°, the sputtering yield increases with the increase of plume divergence half-angle. The magnetic focusing mode that the plume divergence half-angle is controlled to be below 30° can effectively reduce the erosion to wall caused by ions, which will improve the thruster life.