Rf modes and plasma formation of electron cyclotron resonance ion source

Abstract

The plasma chamber of electron cyclotron resonance (ECR) ion sources may be considered as a cavity resonator in radio-frequency (rf) technology. The microwave frequency then has to be tuned to the resonant frequency of a preferable mode. In order to produce ions with higher charge state, the rf characteristics of the plasma chamber should be investigated. As the first study, the rf simulation and the experimental measurement were carried out for a permanent magnet ECR ion source, which was developed at Tokyo Institute of Technology (TokyoTech). The frequency spectrum of microwave power transmission was measured to check the resonance points of the plasma chamber. The mode analysis was performed by a theoretical calculation and with a three-dimensional simulation code. These results and the effect of the electric-field distribution on ECR plasma will be presented.