Effects of aperature diameter and gas flow rate on a piezoelectric plasma propulsion system

The effects of varying aperture size and gas flow rate on the output electron current, distribution of ion energies and resulting thrust of a piezoelectric plasma propulsion system are assessed. An rf driven lithium niobate crystal was used to generate the plasma in a small vacuum chamber pressurized with argon gas. Flow rates of the argon gas and aperture diameters were independently varied to determine an optimal operating design. Electron and ion energies were measured by retarding potential analysis from 500 V to 3 kV in 500 V increments to determine the energy distribution of the ejected plasma. A torsional balance with a laser interferometer setup was also developed to measure resulting thrust from each configuration. This presentation will detail the experimental configuration used to generate the plasma, the diagnostic design and the resulting electron currents, ion energies and thrust corresponding to the varied conditions.