We demonstrate experimentally that there is a strong link between electron transport and ion transport in sputtering magnetron plasmas. Electron densities and discharge currents for He, Ne, Ar, Kr, and Xe discharges are measured and used to infer the charged particle confinement time. We find that the confinement time increases with ion mass. Further we find fair agreement between the experimental results and a model which assumes that ion motion is collisionless and unmagnetized, and that the spatial dependence of the electric potential and ion source are similar in the different discharges. © 1990, American Vacuum Society. All rights reserved.