Abstract: The effects of discharge voltage and screen grid voltage changing to working performance of a 6 cm Kaufman ion thruster were studied by combination of experiments and numerical simulation. In these experiments, the argon was used as propellant for the ion thruster,and many groups of data were gathered. Furthermore, based on Goebel′s theory model,the effects of discharge voltage changing on beam current and propellant efficiency were simulated.And the particle in cell Monte-Carlo collide (PIC-MCC) theory was used to simulate the effects of screen voltage on beam current, propellant efficiency and acceleration grid current. Experiments and numerical simulation drew the same conclusions. When discharge voltage increases, ion beam current and propellant utilization efficiency tend to be stable after a corresponding increase. A similar beam electric current and propellant utilization efficiency changing pattern is observed when the screen grid voltage is increased,but acceleration grid voltage tends to be stable after a corresponding decrease. This study can provide a reference for increasing multimodes ion thrusters' performance.

Key words: ion thruster, multi modes, discharge voltage, screen grid voltage, argon