in an r . f . glow discharge system , a plurality of hollow electrodes are positioned circumferentially about a central point forming a circular array or squirrel cage . a workpiece is supported within the squirrel cage and relative rotational movement between the squirrel cage and the workpiece is provided . a plurality of apertures are provided along the surface of each electrode and aligned toward the surface of the workpiece . alternatively , each electrode may further consist of a pair of inner and outer hollow tubes each with a plurality of apertures along its length with the apertures of the inner tube being adjacent to and spaced from the apertures of the outer tube but offset therefrom . the arrangement is best suited for a cylindrically shaped workpiece , e . g ., a photoreceptor drum .