Characteristics of Ion–Ion Thruster Generating Continuously Positive and Negative Ion Beams

The neutralizers in ion thruster systems do not generate thrust force. Hence, the power consumption of a neutralizer limits the thrust efficiency of the ion thruster system. Therefore, an ion thruster system is proposed that uses a negative ion source that generates thrust force as well as neutralizes the positive ion beam. In this study, in order to verify the feasibility of this ion thruster system by ground experiments, a negative fullerene ion source was developed and three experiments were conducted. First, in order to demonstrate that the satellite can accelerate ions without becoming charged, the positive and negative ion beams were accelerated in the floating condition using a feedback circuit. Second, in order to verify whether the formation of the virtual anode could be suppressed, the space potential and the beam profile in the downstream region of the ion beam were measured. Third, in order to demonstrate that the thruster system generates thrust force, the thrust with a beam target was measured. From the aforementioned results, it was concluded that the experimental verification of the feasibility of the ion thruster with combined positive and negative ions without a neutralizer was successful.