Spatial Profile of Ion Flow Accelerated by Using Electromagnetic Plasma Acceleraerion Method in Electrodeless RF Plasma Thruster*

Electrodeless Radio Frequency (RF) plasma propulsion system is a promising approach to overcome the limitation of operational lifetime caused by erosion of acceleration electrodes. Rotating Magnetic Field (RMF) plasma acceleration method [1,2] is one of the electrodeless concepts and is expected to enhance the performance by means of an additional electromagnetic force [1]. The RMF method drives an azimuthal electron current owing to the non-linear Hall-term effect, and the additional force is generated in the presence of the external divergent magnetic field. To demonstrate our proposed RMF thruster concept, the spatial profile of ion velocity distribution function was clarified by using Laser-Induced Fluorescence spectroscopic measurement method [3]. The addition of the RMF method accelerates plasma flow and the axial component of the ion velocity increases under the magnetic nozzle. We have also investigated a case that the perfect magnetic field penetration of the RMF is not found and a relatively high-velocity increment has been obtained under the partial RMF penetration condition [4].  

[1] S. Shinohara et al, IEEE Trans. on Plasma Sci. Vol. 42 (2014) 1245. [2] T. Furukawa et al, Phys. Plasmas, Vol.24 (2017) 043505, Vol.26 (2019) 033505, AIP Adv., Vol.7 (2017) 115204, and Rev. Sci. Instrum., Vol.89 (2018) 043505. [3] Y. Tanida et al, T. Jpn. Soc. Aeronaut. S., Vol.14 (2016) Pb7. [4] T. Furukawa et al, Phys. Plasmas, Vol.28 (2021) 073507.