Simulation study of the over dense plasma in an electron cyclotron resonance miniature ion source

In this paper, the plasma of a 2.45 GHz permanent magnet miniature ECR ion source has been simulated and discussed. The source with a cylindrical plasma chamber of 50 mm in radius, 50 mm in length, and a maximum input power of 1kW generates a 10 mA, 50 kV proton beam. Considering the long wavelength of the microwave generator (λ0 = 122.4 mm) and the miniature size of the plasma chamber, an alumina window with a relative permittivity of 9 is hired at the entrance of the plasma chamber. Microwave power is injected into the chamber through the window. Microwave power transfer and coupling to the miniaturized plasma chamber of the ion source is the focus of this study. In this way, the strength of the magnetic field, microwave electric field, and spatial and temporal variations of the essential parameters like the density of the microwave power absorption, the Upper Hybrid Resonance (UHR) layer, density, and temperature of the plasma at the starting time of the microwave injection to the ion source chamber are investigated.