Speaker
Description
A Negative-ion based Neutral Beam Injection (NNBI) prototype is under conceptual design in Southwestern Institute of Physics for China Fusion Engineering Test Reactor (CFETR). The aim in the first stage is to extract an H- beam >3A for 1000s and acquire an energy of 200keV. In this presentation, a single beamlet model for optimization of the CFETR NNBI prototype accelerator’s beam optics is developed. The boundary between plasma and beam, namely the meniscus, is calculated with a self-consistent method accomplished in Comsol environment. The optimum perveance is found, which guarantees beam the minimum divergence angle. Magnetic field produced by permanent magnets in the extraction grid is verified to deflect the majority of co-extracted electrons, while inducing a slight offset of the ion beam. As a conclusion, the system is capable to operate as required.
