Effects of the magnetic field intensity on pole erosion of low-power Hall thrusters

Abstract

Magnetic pole erosion is a key life-limiting factor of low-power Hall thrusters. In this study, the effects of the magnetic field intensity near the inner magnetic pole on the pole erosion of a 100 W permanent-magnet Hall thruster at rated operating point were investigated using magnetic field intensity adjustment technology. The experimental results indicate that the erosion rate of the inner magnetic pole decreased considerably with a decrease in the magnetic field intensity near the inner magnetic pole, and the erosion rate can be decreased by over 37.5% when the magnetic field intensity decreased by 20%. Further analysis indicates that the decrease of magnetic field intensity reduces the number of electrons moving along the magnetic field lines to the magnetic pole, and increases the surface potential of the magnetic pole. The reduction of the potential difference between the channel outlet and the magnetic pole leads to a decrease in the current density and energy of the ions sputtered to the magnetic pole, which contributes greatly to the decrease in pole erosion rate. This study provides a reference for the protection of magnetic pole erosion.