Finite ion cyclotron radius effects upon the ion probe current

Resonant effects upon the ion current to electrical probes in a magnetic field are presented. When the ion cyclotron radius becomes equal to an even fraction of the distance between the double probes, or between the probe and the wall, a sudden decrease or increase in the ion current collection by the probes takes place as a result of resonant plasma depletion or supply between the interacting parts (ion cyclotron radius resonance).