Exhaust Plume Characteristics of Microhollow Cathode Discharge Plasma Thruster

A microscale plasma thruster in a microhollow cathode discharge configuration is tested in dual-stage operational mode. Images of exhaust plume in various operating conditions are presented. The first-stage-only mode exhibits very weak exhaust plume at an 80 SCCM argon gas flow, while in the second-stage-only mode, despite the same power input, the exhaust plume is significantly enlarged. Dual-stage operation without a gas flow produces the largest exhaust plume resulting from electrostatic acceleration.