  The magnetic field of the permanent magnet electron cyclotron resonance (ECR)
ion source SWISSCASE located at the University of Bern has been numerically
simulated and experimentally investigated. For the first time the magnetized
volume qualified for electron cyclotron resonance at 10.88 GHz and 388.6 mT has
been analyzed in highly detailed 3D simulations with unprecedented resolution.
The observed pattern of carbon coatings on the source correlates strongly with
the electron and ion distribution in the ECR plasma of SWISSCASE. Under certain
plasma conditions the ion distribution is tightly bound to the electron
distribution and can considerably simplify the numerical calculations in ECR
related applications such as ECR ion engines and ECR ion implanters.
