Gradual increase in secondary ionization coefficientγand charge accumulation on a dielectric electrode during DBD with repeated breakdown

Abstract

We have investigated the effect of the surface roughness of a dielectric electrode for dielectric barrier discharge (DBD). We prepared three alumina plates made from the same material with different surface roughnesses for use as electrodes. During the repeated breakdown from the first breakdown to the stationary state, we observed gradual increases in the secondary ionization coefficient and the charge accumulated on the alumina electrodes under the application of a sinusoidal voltage in argon up to a pressure of 105 Torr. A strong correlation was also observed between them, similarly to in a previous paper on CaO film electrodes. The results suggest that increasing the surface roughness of an alumina electrode results in a larger secondary ionization coefficient and greater charge accumulation on the electrode. Moreover, it is concluded that the charges that accumulate on the alumina can be liberated from the surface as initial electrons when it acts as a cathode, depending on the polarity of the alternating gap voltage. These electrons induce the formation of an atmospheric-pressure Townsend discharge. Finally, we discuss the effect of the secondary ionization coefficient in DBD.

The effects of the tube diameter on the discharge ignition and the plasma properties of atmospheric‐pressure microplasma confined inside capillary

“…In addition, the charges accumulation on the wall may also provide additional seed electrons for the discharge ignition, which plays an important role in the lower ignition voltage and the formation of the Townsend discharge in DBD. [42] However, there is lack of enough consistent information concerning the effect of surface charges on the discharge ignition and the ionization wave propagation inside the capillary. A future work on the measurement of the surface charges inside capillary is required to address this issue.…”

“…When the voltage polarity is reversed, the surface charges will enhance the electric field. In addition, the charges accumulation on the wall may also provide additional seed electrons for the discharge ignition, which plays an important role in the lower ignition voltage and the formation of the Townsend discharge in DBD . However, there is lack of enough consistent information concerning the effect of surface charges on the discharge ignition and the ionization wave propagation inside the capillary.…”

The influences of the electrode dimension and the dielectric material on the breakdown characteristics of coplanar dielectric barrier discharge in ambient air

“…Another possible factor is the surface charge accumulated on the dielectric surface, which is largely dependent on the types of dielectric material . Li et al reported that the desorption of the trapped electrons on the dielectric surface can provide seed electrons for the diffuse discharge.…”

“…Another possible factor is the surface charge accumulated on the dielectric surface, which is largely dependent on the types of dielectric material. [30][31][32][33][34][35] Li et al [31] reported that the desorption of the trapped electrons on the dielectric surface can provide seed electrons for the diffuse discharge. Radu [36] found that the trapped charge on the dielectric surface reduces the propagation velocity of the discharge across the gap and increases the width of the discharge channel.…”

Electron avalanche statistics for multielectron initiation with homogeneous and inhomogeneous Poisson emission

“…From our experience [23], as well as from the results in the literature [24][25][26], the electron emissivity of the cathode (electron yield) may increase/decrease with a large number of repeated light illuminations or particle irradiations. Namely, the adsorption/desorption of gases and impurities, roughening or smoothing of the cathode surface due to sputtering, cleaning, aging, etc.…”