Abstract
One of the challenges that plasma research encounters is how to generate a large-scale plasma plume at atmospheric pressure. Through utilizing a third electrode biased by a direct-current voltage, a longer plasma plume is generated by a plasma jet in dielectric barrier discharge configurations. Results indicate that the plume length increases until it reaches the third electrode with increasing the bias voltage. By fast photography, it is found that the plume consists of two types of streamers under the influence of the bias voltage, which develops from a guided streamer to a branching one with leaving the tube opening. The transition from the guided streamer to the branching one can be attributed to the electric field and the air/argon fraction.