Spatial distribution of radiation emitted by pulsed surface dielectric barrier discharge in air

Abstract

The dynamics of radiation intensity at 337 nm emitted by the surface dielectric barrier discharge driven by 50 ns duration and 8 kV amplitude voltage pulse of both polarities has been analyzed experimentally and numerically. The calculations were performed in a 2D approach for experimental conditions to check the existing numerical models and understand what processes manage the discharge length and the spatial distribution of the discharge radiation intensity. Experimentally measured and numerically simulated profiles of radiation intensity along the discharge length notably differ from each other and the performed modification of the discharge physical model does not essentially change this difference. Radiation intensity from the discharge channel has been shown to be extremely sensitive primarily to the value of reduced electric field. We suppose that the discrepancy between experiment and numerical simulation could be due to 2D instead of 3D simulation and corresponding incorrect estimation of electric field distribution along the discharge channel. The numerical simulation of discharge length is in good agreement with experiment for the discharge stroke at the leading front of the voltage pulse and gives few times less values for the backward discharge at the trailing edge of the voltage pulse.

Numerical verification of the two-spike-current behavior in the initial stage of plasma formation in a pulsed surface dielectric barrier discharge

“…Since the influence of the environmental factors is rather complex, this will inevitably affect the discharge characteristics. On the other hand, the conditions in the simulation model are spontaneously idealized [42]. Thus the calculated breakdown voltage (about 1.5 kV) and the peak value of the first spike (about 1 A) in the simulations are lower than that in the experiment (about 3 kV and 2 A, respectively).…”

Is an extended barrier-free discharge under nanosecond-pulse excitation really diffuse?

“…The maximum electron density occurs at the HV electrode first, then decreases slightly during the propagation of the primary streamer and rises again as the plate is approached. After the discharge front has passed by, the reduction of T e in the channel makes n e decrease due to rapid recombination processes, for example e + O + 4 → 2O + O 2 with a rate of 1.4 × 10 −12 (300/T e ) 0.5 [45,46], especially near the HV electrode. The drop in n e weakens the shielding effect caused by space charge in the channel, and the high potential applied on the HV electrode is maintained; both these effects make E near the knife tip exceed the breakdown threshold again and trigger the secondary streamer [45].…”

“…The initial electron density before the next pulse can be enhanced. During the interval between two consecutive nanosecond pulses, the electron density n e decays due to dissociative recombination [45,46] n e (t) ≈ n e,max 1 + k r n e,max t . Since O + 4 is the main positive ion in the discharge channel during the late afterglow for atmospheric air [47], k r = 1.4 × 10 −12 (300/T e ) 0.5 is taken as the dissociative recombination of electrons with O + 4 ions [45,46].…”

“…During the interval between two consecutive nanosecond pulses, the electron density n e decays due to dissociative recombination [45,46] n e (t) ≈ n e,max 1 + k r n e,max t . Since O + 4 is the main positive ion in the discharge channel during the late afterglow for atmospheric air [47], k r = 1.4 × 10 −12 (300/T e ) 0.5 is taken as the dissociative recombination of electrons with O + 4 ions [45,46]. The maximum electron density n e,max is around 10 20 m −3 (details are shown in the appendix) and t is 20 ms with pulse repetition of 50 Hz.…”

Gasdynamic Flow Control by Ultrafast Local Heating in a Strongly Nonequilibrium Pulsed Plasma

“…Two-dimensional modeling of SDBD makes it possible to obtain reasonable agreement between experimental data and calculations for integral discharge characteristics: the limiting length of the discharge development [62,63], discharge current [62], and energy deposition [64]. Attempts to compare the calculation with experiment for more detailed characteristics of the discharge-the time evolution of radiation from the discharge plasma-turn out to be less successful [63].…”