Magnetic confinement less microwave discharge gridded ion thruster

Abstract

A watt-level microwave discharge is induced without magnetic confinement for a high-precision gridded ion thruster, making use of a coaxial transmission line resonator. The thruster is characterized by performance measurements and plasma diagnosis, and a description of the operating mechanism of this thruster is given in this paper. A Faraday probe and a retarding potential analyzer are employed for the diagnosis. The results show that the plume divergence increases due to the electric field formed between the plume and the ion-induced electron emission cathode. A discharge mode transition is found during the increase of the microwave power, in which the bulk heating mode is converted to the surface heating mode. The magnetic-less microwave discharge gridded ion thruster performs a continuously adjustable thrust range of 5–115 μN and a highest total efficiency of 17.2%. Compared to the common ECR ion thruster, this thruster is free from magneto-static interference on the instruments and the additional magnetic momentum on the spacecraft.

Simulation of filamentation dynamics of microwave discharge in nitrogen

“…An important advantage of MW discharges is the possibility of electrodeless energy deposition to the plasma at a relatively low electron temperature. One of the modern areas of experimental research is the use of electrodeless MW discharges in rocket engines [17,18], plasma engines [19,20], and aerodynamic applications [21][22][23][24][25][26][27][28][29]. In particular, experimental studies have shown high efficiency of such discharges from the point of view of energy deposition to supersonic and hypersonic flows for the flow control and drag reduction near aircraft moving in the atmosphere [21][22][23][24][25][26][27][28][29].…”