Modeling of electron cyclotron resonance ion source plasmas

A computer model for both electrons and multiple ion species in an Electron Cyclotron Resonance Ion Source (ECRIS) plasma that is ID spatially has been developed. The non-Maxwellian anisotropic electron-distribution-function (EDF) is modeled using a ID axially bounce-averaged Fokker-Planck code that is 2D in velocity space (velocity and pitch angle). ECR heating is treated using a quasi-linear rf-diffusion term including relativistic detuning and rf pitch-angle scattering. Under typical ECRIS conditions, the electrons are very non-collisional and magnetically confined. Thus, the ions must follow the electron confinement via the electrostatic potential. The ion species are assumed to be highly collisionally coupled and are treated using a 1D fluid model characterized by a single fluid velocity. Ion charge-state-distributions (CSD) flowing into the extraction aperture can be calculated and used as input to an ion beam extraction code. The modeling reproduces several experimentally observed characteristics of ECRIS plasmas