Experimental Study on EHB Type Ion Source

In the design of high current ion sources, for applications to NBI (Neutral Beam Injection) heating of fusion plasma, it is important to obtain hydrogen plasma with high proton ratio. In order to improve the properties of plasma parameters, i.e. plasma density and electron temperature, and to control the composition of extracted ion beams, we have developed the EHB (Electron Heating in Bucket) Type Ion Source. In this device, DC discharge in the bucket type configuration of magnetic field is combined with electron heating due to microwave. The multipole line cusp field is used for resonance magnetic field of electron heating as well as confinement field of plasma. It is verified that superposed RF power affects the overdense plasma (plasma frequency &fnof