Electrodeless Plasma Propulsion with Electromagnetic Acceleration Effect by Using Rotating Magnetic Field Current Drive Method

摘要

Electrodeless plasma thruster, which has no direct interaction between electrodes and plasma in plasma generation and acceleration phases, is being proposed to solve originally existing issues, including lifetime limitation of the thruster and degradation of the thrust performance. As one of the electrodeless concepts, an rf (radio frequency) plasma thruster using Rotating Magnetic Field (RMF) current drive method is being proposed and studied. This RMF method is expected to generate an axial Lorentz force by a cross product of the azimuthal electron current and a radial component of an external divergent magnetic field source to additionally accelerate the plasma flow in the vicinity of the magnetic field nozzle area. Here, the amplitude of an ac current applied to the RMF antenna was increased to enhance the current drive efficiency. Hereby, the plasma acceleration effect was found in the downstream of the RMF antennas. Furthermore, the RMF application affected plasma flow spatially, and the expected acceleration effect was also found. Higher original RMF current density was obtained by spatial measurement of oscillating components of the RMF.