Study on the large-range thrust throttling ability in a multi-cusped field thruster

Abstract

The multi-cusped field thruster represents a type of grid-less electric propulsion concept with a multi-stage magnetic field topology. In this study, a two-stage multi-cusped field thruster is designed. It has a continuous thrust throttle range from 0.37 mN to 19.2 mN with the change of anode flow rate (from 3 to 10 sccm) and anode voltage (from 300 to 1100 V). The performance characteristics show that the thruster is an excellent candidate to fulfill the requirements for space vehicle drag compensation. The large-range thrust throttle-ability is further studied by plasma diagnostic methods. The test results show that the change of anode flow rate mainly affects the propellant ionization process in discharge channel, its influence on acceleration process is less obvious. Besides, the change of anode voltage mainly affects the ion acceleration process near exit, its influence on propellant ionization process is small. These phenomena indicate that there is a weak coupling relationship between ionization region and acceleration region, which becomes an inner decisive factor for its large-range thrust throttle-ability.