Numerical Investigation of Energy Flows in a Magnetic Nozzle Radio-frequency Plasma Thruster

A magnetic nozzle produces a directional flow, which is expected to be utilized as an electric thruster on spacecraft. Mostly, a radio-frequency (RF) plasma source is employed because of the advantages of electrodeless setup. Because a magnetic nozzle does no net work, the energy is provided solely by the RF field. To increase the efficiency, the plasma energy heated by the RF field should efficiently be converted into the directional plasma flow. In recent years, the energy losses in the magnetic nozzle RF plasma thruster have been evaluated in theoretical, experimental, and numerical studies, e.g., the energy lost to the dielectric wall. However, the energy flow from the plasma source to the losses has not been investigated. In this study, the magnetic nozzle RF plasma thruster is simulated using particle-in-cell and Monte Carlo collisions (PIC-MCC) methods. Because the PIC-MCC method treats the kinetics of electrons and ions directly, the energy flow in the magnetic nozzle can self-consistently be evaluated. Two-dimensional energy flows from the plasma source to the downstream region will be presented and discussed in the conference.