Real-time in-situ measurement of inductively coupled power and numerical prediction of power distribution in RF ion thrusters

Abstract

We show a systematical approach to obtain the forwarded electrical power to sustain the plasma discharge in radio-frequency ion thrusters using a commercial current and voltage sensor system. With knowledge of the power directly at the coil, a numerical model delivers the power-to-thrust-ratio as weil as the distribution of power into several channels of loss, including collisions and structural eddy currents. With this work, we are, furthermore, able to distinguish between two phenomena that affect the power-to-thrust-ratio - one caused by the physics of the plasma itself and the other caused by the mismatch of the impedance bridge spanned between the electrical load of the thruster and the driving generator.