A processing system is disclosed, having an electron beam source chamber that excites plasma to generate an electron beam, and an ion beam source chamber that houses a substrate and also excites plasma to generate an ion beam. The processing system also includes a dielectric injector coupling the electron beam source chamber to the ion beam source chamber that simultaneously injects the electron beam and the ion beam and propels the electron beam and the ion beam in opposite directions. The voltage potential gradient between the electron beam source chamber and the ion beam source chamber generates an energy field that is sufficient to maintain the electron beam and ion beam as a plasma treats the substrate so that radio frequency (RF) power initially applied to the processing system to generate the electron beam can be terminated thus improving the power efficiency of the processing system.