A two-dimensional fluid model is established to study the effect of an external electric field and its amplitude on the He atmospheric pressure plasma jet (APPJ) impinging to the dielectric surface process. The self-established electric field between the charge at the jet head and the external electrode causes the change of propagation speed and intensity of APPJ. The radial component is generated when the jet develops down the axis, which results in the change of the jet width. Under the external asymmetric voltage, the jet center deviates from the central axis. The self-established electric field between the charge at the jet head and the external electrode and the radial electric field generated by the accumulated surface charge guide the radial propagation of the jet. Higher ionization rate, radial mean propagation velocity, and wider radial development range can be obtained under external negative voltage. Additionally, excessive external voltage amplitude may lead to the generation of parasitic ionization waves.
Wang et al. (Sun,) studied this question.