Experimental and numerical studies of a direct current microdischarge plasma thruster

A simple Microdischarge Plasma Thruster (MPT) for small satellite propulsion has been designed and studied by performing experiments and running simulations with a numerical model. The MPT comprises a tri-layer sandwich structure with a dielectric layer sandwiched between two electrode layers, and a contoured through-hole drilled into the structure. Each layer is a few hundred micron thick and the hole diameter is also of approximately this size. The device operates at Ar flow rates of ∼1 sccm with moderate electrode voltages (∼1000 V). Spectral measurements of the plume are used to determine its composition and calculate the electron excitation temperature. A two-dimensional computational model has been developed to provide a detailed description of plasma dynamics inside the MPT including power deposition, ionization, coupling of plasma phenomena with the high-speed flow, and propulsion system performance. Gas heating, primarily due to ion Joule heating, is found to have a strong influence on the overall discharge behavior