Analysis in microwave-driven plasma for miniature space propulsion

Abstract

Microwave-driven Coaxial Transmission Line Resonator (µ-CTLR) produces a small-volume high density plasma plume. In the previous study, we discovered that the plasma generated by the µ-CTLR remains stable even at low pressure around tens of mTorr, while consuming minimal power below 10 W (Kim et al 2022 Plasma Sources Sci. Technol. 31 105006). In this study, we have investigated the capability of the µ-CTLR plasma operating at 900 MHz for micro-propulsion applications. At the argon gas flow rate of 100 SCCM (3 mg s⁻¹), and the power of 8 W, the plasma plume attains high gas temperature ( >3000 K), high electron density ( >1020 m−3), and electron temperature of about 2 eV. The estimated thrust is about 3.4 mN, demonstrating that the µ-CTLR has high thrust desirable for space micro propulsion systems, together with the other merits of low power consumption and small size.