Abstract: In order to study the thermal radiation influence of the sputtering target on the ion thruster in vacuum facility, finite element analysis was adopted to simulate the plume distribution of the thruster in vacuum chamber. Having obtained the temperature variation of the sputtering target caused by the influence of plume on the target, variation of temperature and thermal deformation of the grids caused by the increase of the sputtering target temperature were analyzed. The results show that the thruster plume can be described by a directional molecular flow model, and there was almost no energy loss in the plume diffusion process. The gas pressure in most areas of the vacuum chamber was in the range of 2×10^-3 Pa to 6×10^-3 Pa when the thruster was working. Under the influence of the sputtering target, the central temperatures of the accelerator grid and the screen grid were 352℃ and 440℃, and the edge temperatures were 342℃ and 411℃, respectively. The reduction of the gap between the screen grid and the accelerator grid increased from 0.560mm (without the sputtering target) to 0.585mm. The experimental results show that the temperatures at the edges of the accelerator grid and the screen grid were 364℃ and 385℃ respectively, with an error of 6% compared with the test results. The temperature test value of the plume at the rear of the sputtering target was about 50℃ higher than that in the simulation results, and the error was due to the neglection of the energy deposition of plume particles in simulation.

Key words: ion thruster, neutral plume, sputtering target, thermal radiation, the grids hot gap, electric propulsion