Microwave electrothermal thruster with surface wave plasma

Abstract

A new microwave electrothermal thruster (MET) with small dimensions (length of 25 mm and diameter of 6 mm), utilizing surface wave (SW) plasma at low average power consumption Pav ˜ 2 W, is made. It uses microwaves at a frequency of 2.45 GHz for plasma generation within a dielectric chamber enclosed in a metal shield. The SW is excited at the plasma‐dielectric interface by a coaxial launcher and a standing wave is created due to the wave reflection from the shield. The high‐density plasma produced in this resonant chamber heats up the argon gas, which expands through the nozzle in the axial direction. The temperature of the gas decreases from 1900 K at atmospheric pressure to 1200 K at 10 Torr ambient pressure. This small‐sized MET shows stable low‐pressure operation with a thrust of 4 mN and an efficiency of 8% and is suitable for nanosatellite orbit control.