Development of Variable Time-Averaged Thrust System by Controlling Duty Ratio of Ion Beam Extraction in Ion Thrusters

Abstract

For the demonstration of wide variable thrust range ion thruster, ion beam extraction ON/OFF duty ratio controlling system was developed. We measured the ion beam current trace at downstream of the ion thruster with ON/OFF duty ratio control. In addition, we investigated the effect of this system on the ion beam divergence. The ion beam current changed as the applied voltage changed, that is, we demonstrated the system was useful for extending the thrust range. Beam divergence was almost constant, about 20 degree while changing duty ratio from 1% to 100%; this results shows that variable thrust system with controlling the beam extraction ON/OFF duty ratio affects little on the beam divergence.