Influence of coil structure and position on the performance of miniature radio frequency ion thrusters

Abstract

In this article, the influence of coil structure and position on the energy coupling efficiency of the miniature radio frequency (RF) ion thruster (μRIT) HRIT-4 with a diameter of 4 cm was studied. The experimental results show that the performance of the thruster can be improved by increasing the number of coil turns or decreasing the turn spacing, but if the distance between the coil and the screen grid is too small, the performance of the thruster will be significantly reduced. It is found that increasing the number of coil turns or decreasing the turn spacing will increase the resistance of the coil itself, but it will also obviously increase the inductance. Increasing the number of coil turns will also increase the resistance of the plasma source, and finally improve the performance of the thruster. On the other hand, due to the mutual inductance between the coil and the screen grid, the mutual inductance will be enhanced when the distance between the coil and the screen grid is reduced, and the mutual inductance will reduce the inductance of the thruster and increase the resistance of the thruster, eventually leading to the performance degradation of the thruster.