Comparative study on the matching relationship between antenna and segmented electron cyclotron resonance (ECR) layer on miniature ECR discharge neutralizer performance

Electron cyclotron resonance (ECR) discharge neutralizers, with advantages such as high controllability, simple structure, long lifespan, and multi-gas compatibility, show promising applications in emerging working fluids. Their performance is primarily determined by their magnetic field topology, exhibiting significant variations under different configurations. This work investigated the impact of the matching relationship between the antenna and the segmented ECR layer on the performance of a 2 cm radial magnetic mirror field ECR discharge neutralizer. By comparing the performance and plasma parameters of the neutralizer at different antenna radial positions, a reasonable matching relationship between the magnetic field of the antenna and the segmented ECR surface is obtained, and the plasma parameters are obtained by the spectral imaging diagnostic method. The results indicate that the performance of the ECR discharge neutralizer is better when the antenna is matched to the outer ring ECR layer. The outer ring antenna yields a 1‒3 mA higher extraction current than the inner ring antenna during microcurrent extraction, representing 25%‒50% of the total current. In addition, spectral imaging results show that the ionization rate of the working fluid in the discharge chamber is increased by about 3% compared with the matching of the antenna and the inner loop ECR surface. This is due to the higher energy conversion efficiency of the microwave when the line is matched to the ECR surface of the outer ring.