This paper describes the measurements of plasma density distribution very near the ion optics in the discharge chamber of an ion thruster and this is of particular value in designing the ion optics and magnetic configuration in the discharge chamber. We had replaced the original dished grids of a 25-cm ion thruster by plain grids to make all the gridlets identical and measured ion current from the gridlets on a grid radius using a collimated Faraday probe. The plasma density very near the ion optics are related with the ion current and the density distribution was obtained by making a hypothesis. The density distribution was related to the field strength in the discharge chamber.
25㎝イオンスラスタ放電室内グリッド近傍のプラズマ密度分布測定
