Experimental Investigation of Microhollow Cathode Discharge for the Application to Microplasma Thrusters

As to microhollow cathode discharge (MHCD) in argon, the discharge characteristic was analyzed, the gas temperature was determined from the emission spectroscopy with traces of nitrogen added, and the electron density was also evaluated through the Stark broadening of the Balmer Hβ line from hydrogen as trace impurity in the gas. The electron density is in the order of 1014 cm−3 and increases with the increasing gas pressure and discharge current. The gas temperature also increases with the increasing pressure and current, and can reach 1000 K in the stable glow regime. The results show that the extremely small dimensions of the MHCD combining with relative intense and controllable gas heating can be applied as a new micro electro-thermal thruster for micro-satellite propulsion. Due to the heating of the propellant gas in the microdischarge plasma and its expansion through the micro-nozzle, the performance of specific impulse and thrust of the microplasma thruster using the MHCD will be higher than the conventional cold gas microthrusters.