Numerical simulation study on barrel erosion of ion thruster accelerator grid

The barrel erosion, one type of accelerator grid erosion in an ion thruster, is important and needs more detailed studies. In this paper, a three-dimensional numerical simulation code is developed using a hybrid immersed-finiteelement particle-in-cell method and Monte Carlo collisions method; the dynamics of a neutral atom is modeled using a direct simulation Monte Carlo method; and a numerical simulation study is run to investigate the mechanism of aperture barrel erosion of an ion thruster accelerator grid. Simulation results indicate that the aperture barrel erosion of ion thruster accelerator grid is entirely caused by the charge-exchange ions under nominal operating condition, and the incident charge-exchange ions in four regions, namely the upstream region, the extraction (center) region, the extraction (edge) region, and downstream of the accelerator grid, are the causes of aperture barrel erosion. Highenergy charge-exchange ions originated from upstream region are not well focused and play an important role in the erosion of the aperture barrel. Charge-exchange ions originated from the extraction (center) region, which play an important role in the whole incident charge-exchange ions, also cause significant erosion on the aperture barrel. It is therefore believed that these findings would facilitate the prediction of aperture barrel erosion of an ion thruster accelerator grid.