‘Memory’ and sustention of microdischarges in a steady-state DBD: volume plasma or surface charge?

Abstract

The results of a numerical study on the spatio-temporal behavior of transient microdischarges (MDs) in a steady-state dielectric barrier discharge (DBD) excited by a sinusoidal voltage are presented. MDs have a spatial 'memory'-every subsequent MD appears at exactly the same location occupied by the MD at the preceding half-period (HP). In the majority of cases each MD appears at its location only once during every HP. For such a case, the memory effect is not attributed to the residual surface charge deposited by the preceding MD but determined by the residual MD plasma column shunting the gap right up to the beginning of the next HP. In contrast to good memory in space, each individual MD has a large scatter with time in its appearance within every HP, i.e. there is no 'memory' concerning the phase of an applied voltage. This MD jittering within the period is attributed to the stochastic nature of partial surface breakdowns around the bases of the MD plasma column. Numerical calculations show that surface breakdown provides an MD current splash at every HP. Hence, in the steady-state DBD, the volume plasma is responsible for the existence of MD spatial 'memory' (i.e. where the MD appears), and the deposited surface charge is responsible for MD jittering in time (i.e. when the MD appears).

Dynamical level-crossing model for the time-dependent electron emission from dielectric surfaces in symmetric dielectric barrier discharges

“…In the case of dielectric-gas-dielectric systems under AC voltage, degeneracies between localized states within and outside the dielectric surface appear due to time-dependent energy level crossing, leading to the possibility of time-dependent electron transfer. The temporal profile of current-voltage phase lag, as well as surface charge accumulation and depletion obtained from our computations using simple energy level crossing arguments, are consistent with experimental observations in the literature [32][33][34][35], but quantitative agreement with experiments requires more detailed computations coupling electron transfer from dielectric surfaces with the kinetics of plasma formation, and are beyond the scope of this work. difference is applied, a linear potential drop is expected across various insulating parts of the device, according to their relative permittivity r , and we are interested in the timedependent transfer of electrons from the dielectric into the gaseous argon under a timedependent potential V ext (t).…”

“…The Finally, we note that the total number of electrons in the isolated system is held constantas such, electron transfers result in charge depletion (holes) and accumulation (electrons) on the dielectric surfaces. The computation of charge depletion and accumulation complements recent phenomenological and experimental investigations of surface effects such as surface charge accumulation and depletion, memory effects on microdischarge formation, and surface charge transport [32,34,35]. However, surface charges can also be transported towards metallic contacts, and recent works have investigated electron absorption and subsequent transport in dielectric materials, and the associated effects of phonons and impurities [36][37][38][39].…”

Design and evaluation of plasma polymer deposition on hollow objects by electrical plasma generated from the liquid surface

“…Electrical characteristics of the discharge were monitored by a digital oscilloscope Keysight DSOS204A oscilloscope connected to a voltage and current probes. The electrical discharge contains a large number of small current pulses predominantly in positive half‐cycle, which is in a good correlation with our previous measurements or according to Akishev et al that practically no streamers are visible during the negative polarity . Resonant frequencies and applied voltages ranged from 27 to 29 kHz and 13–17 kV, depending on the side and the mode of treatment.…”

Diffuse Coplanar Surface Barrier Discharge in Artificial Air: Statistical Behaviour of Microdischarges

“…The theory of the so-called 'memory effect' [42][43][44] of DBD says that the time and space appearance of microdischarges is influenced by the remnant electric charges and the excited species in the process gas and on the surface of dielectric barriers. It implies that the reappearance of microdischarges at the close places within the single halfperiod of the discharge is suppressed by the developed space charge and surface charges which were stored on the dielectric barriers during previous microdischarge event [44].…”

“…In the case of atmospheric pressure DBDs rather microsecond to millisecond timescales are expected [47,48]. Moreover, in the case Instead the remnant active species influence the places of microdischarge occurrence through the distortion of electric field (in case of charged species at the surfaces) and favoring electron production at the pathways of preceding microdischarges (active species in the volume) [42][43][44][45]49,50]. It should be noted also, that the exact processes of 'memory effect' in the case of DBD are not completely understood so far.…”