Abstract
Two-dimensional axisymmetric particle-in-cell simulations with a Monte Carlo collision algorithm, external circuit analysis, and measurements of plasma densities and ion beam currents have been conducted for a micro RF ion thruster. The plasma source of the thruster is 5.0 mm in radius and 10 mm in length with a five-turn helical coil around a cylindrical quartz chamber, where the plasma is generated at low RF powers (< 10 W). The numerical results have indicated that high RF frequencies (> 100 MHz) lead to a high coupling efficiency between the RF power and the plasma, although too high RF frequencies (> 300 MHz) degrade the efficiency. The optimum gas flow rate for ion beam extraction is determined to be 10 μg/s. These results are qualitatively in good agreement with the experimental results, which validates our numerical model, and thus the model would be useful to estimate the performance of the micro RF ion thruster.
