マイクロ波放電式ホールスラスタのチャネル内プラズマ状態および チャネル長さとスラスタ性能の関係

抄録

Microwave discharge Hall thruster can be operated by two operating modes. The first one is “no microwave launching” mode, thus having the thruster operating as single-stage type. The other mode is “microwave launching” mode, thus having the thruster operating as double-stage type. In order to examine the influence of microwave launching mode upon the plasma condition inside the acceleration channel, as well as the relationships between thruster perform­ance and acceleration channel length, single-probe measurements and ion beam energy diagnostics in the plume were carried out. Single-probe measurements revealed the existence of dense plasma and high electron temperature region in the acceleration channel upstream due to the heating of the electrons by microwave. The variation in the discharge current characteristic due to the difference in acceleration channel length was not significant. As for discharge current, double-stage operation always results in a lower value compared to the value at the single-stage operation. Ion beam current was always higher at double-stage operation compared to the value at single-stage operation. Voltage utilization efficiency has improved as the channel length became short with microwave launching.