Influence of surface parameters on dielectric-barrier discharges in argon at subatmospheric pressure

Abstract

The influence of the secondary electron emission coefficient, γ, and the relative permittivity, ɛ r, of the dielectric layers on the characteristics of dielectric-barrier discharges (DBDs) is studied by means of numerical modelling and calculated results are compared with experimental data. The analysis has been performed for a geometrically symmetric, plane-parallel DBD in argon with copper electrodes covered by quartz dielectrics. A time-dependent, spatially one-dimensional fluid model involving the drift-diffusion approximation is applied for the numerical analysis of the DBD operating sinusoidally at a frequency of 24 kHz with applied voltages between 1.8 and 3.4 kV and pressures from 100 to 650 mbar. Main features of the model as well as the experimental setup and procedures are given. The modelling studies show especially the sensitivity of the results on the specific choice of γ and ɛ r regarding the occurrence and intensity of discharge peaks, the appearance of one or more smaller peaks after the main peak, as well the establishment of a single periodic, multiperiodic or even chaotic temporal evolution of the DBD. In particular, generally good agreement between measured and calculated discharge current signals and the power dissipated in the discharge is found for γ = 0.02 and ɛ r = 4.2.

Automated Fluid Model Generation and Numerical Analysis of Dielectric Barrier Discharges Using Comsol

“…These data are provided in the form of look-up tables as a function of the mean electron energy and used as input files for MCPlas. Further details about the reaction kinetics and transport properties are given in [28]. The reflection coefficients of electrons, ions and excited argon atoms as well as the secondary electron emission coefficient and corresponding energy of secondary electrons are taken as in [13].…”

“…2. The model setup is the same as used in Stankov et al [28]. The gap between the 1 mm thick dielectric layers is d = 3 mm.…”

Co-effect of dielectric layer material and driving pulse polarity on the spatial emission intensity distributions of micro dielectric barrier discharge

“…The evolution morphology and breakdown mechanism of DBDs are strongly determined by 'memory effects', including volume and surface memory [26], which are induced by the accumulation of charged particles and residual long-lived particles. In essence, the dynamics of charged particles are governed by the potential profile and electric field distribution in the plasma, which are very sensitive to the dielectric material's properties, especially the secondary electron emission coefficient γ and the relative permittivity ε r [19]. The values of γ and ε r can impact the establishment of periodic development of the DBDs due to volume memory effects [19].…”

“…In essence, the dynamics of charged particles are governed by the potential profile and electric field distribution in the plasma, which are very sensitive to the dielectric material's properties, especially the secondary electron emission coefficient γ and the relative permittivity ε r [19]. The values of γ and ε r can impact the establishment of periodic development of the DBDs due to volume memory effects [19].…”

“…Earlier reported works mostly focused on the influence of a single parameter on discharge properties, such as pressure [13], pulse shape [14,15], repetition frequency [16,17], voltage amplitude [16], pulse rise time [18], dielectric surface parameters [19], and so on. However, the spatial-temporal distributions of microplasmas could be affected by multiple parameters simultaneously.…”