Beam Species Characteristics of High Current Ion Source for EAST Neutral Beam Injector

Abstract

During the experiment of high-current ion source on EAST NBI test bed, the Doppler shift spectroscopy (DSS) is used to measure the hydrogen alpha lines emitted by excited atoms. The multi-peak Gaussian fitting gives the distribution of the original DSS spectra data, the beam energy and the fractions of the beam species can be calculated for different operation parameters of ion source. It is known that the proton ratio increases with the arc power, the beam energy and the perveance, this phenomenon can provide a reference for higher power neutral beam extraction. According to the experimental results, the maximum proton ratio is near 78% under the arc power is about 65kW. This result indicates that the high-current ion source extraction match the design requirements.