A novel and efficient dual-antenna micro plasma thruster

A novel dual-antenna micro plasma thruster (DMPT) driven by radio-frequency (rf) power supply is proposed and characterized experimentally. The Langmuir probe (LP) and the retarding potential analyzer (RPA) are applied to measure the plasma parameters. The results show that compared to the single-antenna, the dual-antenna yields higher electron density, electron temperature, and ion energy. The measurements from the rf I-V probe indicate that the power coupling efficiency for the dual-antenna is about 2.6 times higher than that for the single-antenna. The plasma potential drop in the plume of the DMPT is the reason for the formation of ion beam. The neutral gas temperature is measured by rovibrational ban matching of the first negative band system of ionic nitrogen (N2+) for operating powers of 20 W up to 100 W. The total thrust of the DMPT has been calculated by the sum of the ion thrust and the neutral gas thrust. The total thrust at 100 sccm argon flow rate and 100 W rf power is -2.23 mN, which indicates an up to 168% thrust gain compared to the cold gas thrust, and a significant 11% total thrust is attributed to the ions' electrostatic acceleration. The specific impulse and thruster efficiency at the above experimental conditions are -76 s and -0.8%, respectively. These initial results show that the dual-antenna scheme has better performance and is more promising than the traditional single-antenna design for electrodeless micro-electric propulsion. This novel and efficient micro plasma thruster is particularly useful for cubic satellites and scientific experiments in space (such as gravitational wave detection) which require gesture and orbit control of great precision.