Studies of a direct-current microdischarge based miniaturized plasma thruster

Abstract

Presented are the results of preliminary investigations of a direct-current microdischarge based miniaturized plasma thruster called a Microdischarge Plasma Thruster (MPT). The MPT has a triode con¦guration consisting of electrodes made of molybdenum separated by mica dielectric with argon propellant. Several variations of the triode were studied in order to determine a con¦guration that provided a relatively stable con¦guration. The thruster can produce an intense plume with a bluish outline. Currentvoltage characteristics of the thruster are reported. Preliminary spectral measurements reveal that the plume emission arises from excited ground states of argon, with no emission from argon ions detected.

Simulations Studies of Direct-Current Microdischarges for Electric Propulsion

“…In reality, the cathode temperature probably reaches temperatures even larger than 1000 K, since damage of the molybdenum cathode surfaces of the MPT has been observed experimentally [15]. These results emphasize the importance of managing thermal loads on the cathode by using materials that can withstand high temperatures and the importance of limiting the heat transfer to the cathode to increase the efficiency of the MPT.…”

“…The temperature is fixed at 300 K at the inlet, the outlet, and the solid walls. The selection of this geometry and of these operating conditions was driven by the experimental studies on the MPT performed with a similar micronozzle configuration [15]. An argon gas is considered for this study.…”

“…A new microthruster concept called the Micro Plasma Thruster (MPT) was recently proposed [15]. The MPT consists of a direct-current microdischarge in a geometry comprising a constant area flow section followed by a diverging exit nozzle.…”