A persistent ionization plasma generator is described that forms a plasma in a cavity that persists for a time after termination of the exciting RF electric field. The plasma generator includes a RF cavity that is in fluid communication with a source of ionizing gas. The RF cavity can be at substantially atmospheric pressure. An RF power source that generates an RF electric field is electromagetically coupled to the RF cavity. An ultraviolet light source is positioned in optical communication to the cavity. An antenna is positioned within the cavity adjacent to the ultraviolet light source. A chamber for confining the plasma can be positioned in the cavity around the antenna.