  Three-dimensional numerical model is developed and applied for studies of
physical processes in Electron Cyclotron Resonance Ion Source. The model
includes separate modules that simulate the electron and ion dynamics in the
source plasma in an iterative way. The electron heating by microwaves is
simulated by using results of modelling the microwave propagation in the plasma
by the COMSOL Multiphysics software. Extracted ion currents and other
parameters of the source are obtained for different gas flows into the source.
It is observed that the currents are strongly influenced by ion transport in
transversal direction induced by the plasma potential gradients. Impact of some
special techniques on the source performance is investigated. Magnetic field
scaling is shown to reduce the ion losses during their movement toward the
extraction aperture, as well as use of the aluminum chamber walls and mixing of
the working gas with helium.
