Thrust Characteristics of High-Density Helicon Plasma Using Argon and Xenon Gases

Abstract

A helicon plasma thruster has been studied to develop a completely electrodeless electric thruster using high-density helicon plasmas. The proposed helicon plasma thruster involves two processes: the generation of source dense plasma by using a helicon wave, and the additional acceleration of the generated plasma by using the Lorentz force generated by the product of the induced azimuthal current and external radial magnetic field. This additional acceleration method requires additional electrodes or coils, leading to a longer discharge tube. Therefore, it is necessary to find a good configuration that minimizes wall losses within the discharge tube. Here, thrust characteristics such as thrust, thrust-to-power ratio, specific impulse, and thrust efficiencies of argon and xenon gases were studied, using a radio frequency of 7 MHz and an input power less than 3 kW, to optimize the target plasma without employing an additional acceleration method. A helicon plasma source, with electromagnets and permanent magnets, was used to generate a flexible divergent magnetic field, and a target-type cylindrical thrust stand was installed in a large buffer chamber (volume: , pumping speeds: 1000 and ). In the case of argon gas, the maximum thrust and the thrust-to-power ratio were 21 mN and , respectively, whereas in the case of xenon gas, these values were 40 mN and , respectively.