Measurement and control of the streamer head electric field in an atmospheric-pressure dielectric barrier plasma jet

The propagation dynamics of an atmospheric-pressure plasma jet resemble that of a cathode-directed streamer and are determined, in part, by the high localized electric field at the streamer head. This contribution employs an optical spectroscopy technique based on the polarization-dependent Stark splitting and shifting of visible helium lines to non-invasively measure the streamer head electric field. It is demonstrated that the streamer head is comprised of a high-field region with a peak magnitude of ∼24 kV cm−1, which is followed by a low-field region, ∼9 kV cm−1, identified as the streamer tail. The application of varying polarity voltage pulses to supplementary electrodes situated along the axis of streamer propagation is shown to influence the streamer head electric field and affords a level of control over the propagation dynamics of the plasma jet, a finding that has considerable application potential.