STUDIES IN HIGH FREQUENCY DISCHARGES

Abstract

A qualitative theory of the nature of high frequency discharges, with special reference to those developed by the use of external sleeve electrodes, is advanced on the assumption that the discharge is largely determined by its d-c. wall and space charges, and that the chief function of the high frequency field is to maintain the electron temperature. This theory leads to the conclusion that there must be a high negative wall charge under the electrodes, and a high radial field tending to drive positive ions to the walls. Thus each electrode has many of the characteristics of a cathode in a d-c. discharge. This conclusion is verified by the appearance of the high frequency discharge and by a careful examination of deposits resulting from the removal, by positive ion bombardment of the tube wall, of thin metallic films and of materials of which the discharge tube itself is composed.