Abstract
A series of experiments designed to yield information on the mechanisms of ultra‐high frequency discharges which influence the operation of ion sources employing such discharges is described. The main conclusions are that such discharges exhibit a high negative space charge due principally to secondary emission from the walls of the discharge chamber and that ion production is inhibited by the space‐charge trap so formed, that under certain conditions extremely intense electron beams may be obtained from a resonant cavity containing a gas discharge, and that fairly large ion currents may be obtained by the interaction of the emergent gas and the emergent electron beam in the exit orifice of the cavity.