Microwave electrothermal thruster with surface wave plasma

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 P_av ˜ 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.