A non‐equal gap distance dielectric barrier discharge: Between cone‐shape and cylinder‐shape electrodes

Abstract

A non-equal gap distance dielectric barrier discharge (DBD) between cone-shape and a cylinder-shaped electrodes is reported. The DBD is driven by a nanosecond voltage pulse. When the pulse frequency is 500 Hz or lower, ladder-shape plasma with multiple plasma layers is generated within the gap, with a distance increasing from 1 to 7 mm. According to high-speed photographs of the plasma captured by an intensified chargecoupled camera detector camera, the ladder-shaped plasma is formed owing to propagation of ring-shaped plasma from the region of the short-gap distance to the region of long-gap distance with regular variations in its propagation speed. The propagation speed drops to zero and lasts for about 20-30 ns at the region of each plasma layer, which results in bright plasma layers. The electric field of the plasma layer at the region of the different gap distance is evaluated according to the optical emission intensity ratio R 391/ 394 of N 2 + at 391 nm and N 2 at 394 nm. The obtained electric field drops from 8.1 to 6.4 kV/mm when the plasma is propagated from regions of gap distance of 2-5 mm. When the pulse frequency is increased to 1 kHz or higher, the discharge changes into a filamentary mode and the multiple-layer plasma disappears.This is an open access article under the terms of the Creative Commons Attribution-NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.

A nonequal gap distance dielectric barrier discharge: Between spiral‐shaped and cylinder‐shaped electrodes

“…(a) Discharge phenomenon of the cone‐shape electrode. [ 26 ] (b) Discharge phenomenon of the spiral‐shaped electrode. [ 26 ] (c) Electric field of the cone‐shape electrode.…”

“…[ 26 ] (b) Discharge phenomenon of the spiral‐shaped electrode. [ 26 ] (c) Electric field of the cone‐shape electrode. (d) Electric field of the spiral‐shaped electrode.…”

“…It is found that the ring‐shaped plasma propagates from the short gap distance region to the long gap distance region with regular variations in speed, forming a ladder‐shaped plasma. [ 26,27 ] The discharge position of these ring‐shaped plasmas is not controllable.…”

“…Recently, we reported two nonequal gap distance DBDs in air, where a wedge‐plane shape and cone‐cylinder shape electrodes are used, respectively. [ 26,27 ] The gap distance of such configuration is not a constant and the plasma in the gap is not ignited at the same time. The discharge current lasts several hundred nanoseconds, which is a much longer time than that of the volume DBDs reported.…”

“…It is found that the plasma appears a ladder shape with multiple plasma layers. [ 26 ] The distance between different layers is believed due to the charge deposited on the dielectric which induces the electric field prohibiting plasma to be ignited next to it. As the total charges of each layer are not easy to control, the distance between each layer can not be controlled.…”