Dynamic Characteristics of Dielectric Barrier Columnar Discharge During Its Decay

This paper pays particular attention to the dynamic characteristics of dielectric barrier columnar discharge after it starts to decay based on a 2-D fluid model. Waveforms of the gas gap voltage, discharge current, and 2-D distributions of the electron density and the equipotential lines were calculated for the steady state of dielectric barrier columnar discharges in atmospheric helium. The evolution process of the discharge during its decay can be divided into four phases: phase (i), in which new discharges occur at nondischarge-column locations after the extinction of the discharge columns; phase (ii), in which the new discharges are extinguished; phase (iii), in which the axial electric field begins to reverse in the gap; and phase (iv), in which Townsend discharges occur at the discharge column locations before entering into the next columnar discharges. Via an analysis of the time evolution of the axial electron density, we show that new discharges occurred at nondischarge-column locations are Townsend discharges. An in-depth study of the reversion process of the axial electric fields at different locations shows that nonuniform accumulated surface charges play a key role in determining the spatiotemporal discharge characteristics. These results contribute toward gaining a comprehensive understanding of columnar discharges.