Geometry Design Optimization of High-Frequency Ion Thrusters and Ion Sources

Abstract

The article presents the results of the computational determination of the optimal design geometry of a certain type of quasi-neutral plasma source. The scheme of an ion source with an inductive plasma discharge formed and maintained by a radio-frequency electromagnetic field in a MHz frequency range is considered. The surface profiles optimization of the main design units – namely, gas discharge chamber and ion extraction system – was carried out via computational modelling. Calculations were carried out using the previously developed engineering model of inductive discharge in plasma. The optimization criteria are the thrust and the value of the ion current extracted from the source, determined from the calculated distributions of electron density and electron temperature within the discharge chamber. Optimization calculations were carried out for an ion source with a discharge chamber diameter of 16 cm on a type of surfaces that are segments of a spherical surface. The results of the thrust calculations are presented in relative values in comparison with the values calculated for the basic configuration of the ion source scheme with a hemispherical discharge chamber and a flat ion extraction system. A significant increase in the value of the extracted ion current and thrust in the determined optimal configuration of the ion source was obtained in comparison with the same values calculated for the basic configuration of the ion source with a hemispherical discharge chamber and flat grids of the ion extraction system.