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离子推力器和航天器的成功整合,需要对羽流-航天器之间可能的相互作用进行全面的评估。为了给二者的整合提供实验依据,设计使用了Langmuir单探针测试系统,对氙气离子推力器束流等离子体参数的空间分布进行了诊断研究。实验中使用栅极表面向外凸出的双栅极Kaufman型离子推力器,真空舱的背景压强为3mPa。与传统静态等离子体不同的是:离子推力器束流等离子体具有很大的定向速度,致使探针电流大幅增加,所以传统静态等离子体条件下的I-V(电流-电位)曲线的解释需要重新考虑并进行适当修正。为了尽量减少定向流对离子饱和电流的影响,实验中选择将Langmuir探针与推力器轴线平行放置。实验结果表明:离子推力器的束流等离子体的悬浮电位、空间电位、离子浓度的变化趋势相似,不同径向位置处的各参数都随着轴向距离的增加而减小。分布图中存在一些参数值较低的特殊点,是因为这些测点并没有位于等离子体束流区域内。通过这些特殊点的轴向和径向坐标,可估计出推力器的束流发散角(16.014°)、栅极半径(在71.3～111.3mm范围之内)、束流形状。
The successful integration of ion thrusters and spacecraft requires a comprehensive assessment of the potential interactions between plume-spacecraft. In order to provide an experimental basis for the integration of the two, a Langmuir single-probe test system was designed and used to diagnose the spatial distribution of the plasma parameters of the beam of the xenon ion thruster. In the experiment, a double-gate Kaufman ion thruster with outwardly protruding gate surfaces was used. The background pressure of the vacuum chamber was 3 mPa. Unlike conventional static plasmas, the ion thruster beam plasma has a large directional velocity and results in a substantial increase in probe current, so the interpretation of the IV (current-potential) curve under traditional static plasma conditions needs to be reconsidered And make the appropriate amendments. In order to minimize the effect of directional flow on the ion saturation current, the experiment was chosen to place the Langmuir probe parallel to the axis of the thruster. The experimental results show that the trend of ionospheric levitation potential, space potential and ion concentration of ion thrusters are similar. The parameters at different radial positions decrease with the axial distance increasing. There are some special points in the distribution that have lower parameter values because these points are not located in the plasma beam current region. Through the axial and radial coordinates of these special points, the beam divergence angle of the thruster (16.014 °) and the radius of the grid (within the range of 71.3-1111.3 mm) and beam shape can be estimated.