The effects of nitrous oxide (N2O) in nitrogen (N2) on the development and morphology of sine-driven dielectric barrier discharges in a single-filament arrangement were studied. Detailed insight in the characteristics of the discharge and its development were obtained from electrical measurements combined with ICCD and streak camera recordings as well as numerical modelling. A miniaturised atmospheric pressure Townsend discharge (APTD) could be generated for admixtures up to 5vol% N2O in N2 although N2O is an efficient collisional quencher of metastable nitrogen molecules. Increasing the high voltage amplitude led to a transition into a hybrid mode with the generation of an intermediate filament in addition to the diffuse, non-constricted APTD. A time-dependent, spatially one-dimensional fluid model was applied in order to study the underlying mechanisms causing the diffuse discharge characteristics. The dataset contains the data shown in the corresponding publication.
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Group | |
Authors | |
Release Date | 2022-11-11 |
Identifier | 656b254e-2a2b-4236-877c-714bd71627f7 |
Permanent Identifier (DOI) | |
Permanent Identifier (URI) | |
Is supplementing | |
Plasma Source Name | |
Plasma Source Application | |
Plasma Source Specification | |
Plasma Source Properties | A symmetric double-sided DBD arrangement with half-spherical, alumina-covered metal electrodes with a gap width of 1 mm was used. The alumina-covered electrodes had a diameter of about 4 mm and a tip radius of about 2 mm. The thickness of the dielectric above the tip was about 0.5 mm. The electrodes were placed in a vacuum tight glass cell. A custom-built sinusoidal high-voltage (HV) power supply (push-pull generator with HV transformer) generating up to 14 kV pp at 10 kHz frequency (f_rep) was used for the operation of the DBDs. |
Plasma Source Procedure | The cell was evacuated by a turbo pump (Pfeiffer TSH261) down to about 10^{−6} mbar before filling the cell with the gas. An additional membrane pump (Pfeiffer MVP 020-3 AC) was used as a process pump in a bypass to set the pressure in the cell to 1 bar. |
Plasma Medium Name | |
Plasma Medium Properties | The gas was virtually pure N2 (≤ 30 ppm O2 in N2, examined by an oxygen sensor (Zirox SGM 7.4)) and N2/N2O gas mixtures with up to 10vol% N2O in N2 at atmospheric pressure. |
Plasma Medium Procedure | The total gas flow through the cell was set to 100 sccm by mass flow controllers connected to gas cylinders (N2, purity 5.0, i.e. 99.999% purity). |
Plasma Diagnostics Name | |
Plasma Diagnostics Properties | The structure and the spatio-temporal development of the DBDs were recorded in the UV and visible spectral range by a fast ICCD camera (Andor iStar DH734-18U-A3) through a quartz glass window. The spatial resolution was about 2 µm, while the maximal temporal resolution was 2 ns. A streak-camera system (Hamamatsu C5680-21C) recorded the spatio-temporal development of the DBDs with about 2 µm spatial and about 20 ps temporal resolution. The high spatial resolution was enabled by a long-distance microscope (Questar QM100). Electrical measurements were performed with current and voltage probes and recorded with an oscilloscope (Tektronix DPO 7254C). The high frequency current transformer (MagneLab CT-F2.5 BNC) provided a high sensitivity (2.5 V/A) with a rise time of 0.7 ns and a bandwidth range between 1.2 kHz and 500 MHz. The voltage probe (Tektronix P6015A) had a bandwidth of 75 MHz. A time-dependent, spatially one-dimensional fluid-Poisson model was used to model the discharge behaviour. The Poisson equation as well as several balance equations were self-consistently solved. While the Poisson equation delivered the potential and the axial electric field, the particle densities and the energy density of the electrons were calculated by the balance equations. The fluxes of heavy particles were determined in the common drift-diffusion approximation. For the particle and energy flux of the electrons, an improved drift-diffusion approximation was used. The accumulation of surface charges at the dielectric surfaces was accounted for by the addition of charged particle fluxes. The reaction kinetics scheme included about 50 heavy particle species and more than 520 reactions. The secondary emission of electrons from the dielectric surfaces by N2(A) impact was considered with a secondary electron emission coefficient of 0.2. The partial reflection and emission of particles was used as boundary condition at the dielectrics with a secondary electron emission coefficient for ion-induced electron emission of 0.02. A quasi-neutral state with an electron density of 10^3 cm^{-3} was used as initial condition. |
Plasma Diagnostics Procedure | Results from electrical and optical measurements as well as fluid modelling were combined to investigate filamentary and diffuse discharge regimes in the given set-up. |
Language | English |
License | |
Public Access Level | Public |
Contact Name | Hans Höft |
Contact Email |
Data and Resources
- Exploring the mechanisms leading to diffuse and filamentary modes - Fig. 5 (neg. half cycle)csv
Axial intensity profiles along the gap axis in dependence on the gas...
Preview Download - Exploring the mechanisms leading to diffuse and filamentary modes - Fig. 5 (pos. half cycle)csv
Axial intensity profiles along the gap axis in dependence on the gas...
Preview Download - Exploring the mechanisms leading to diffuse and filamentary modes - Fig. 6 (U and I)csv
Measured voltage waveform and the corresponding total current (averaged over...
Preview Download - Exploring the mechanisms leading to diffuse and filamentary modes - Fig. 7csv
Applied voltage waveform for 14 kV_pp and corresponding measured currents...
Preview Download - Exploring the mechanisms leading to diffuse and filamentary modes - Fig. 8 (U and I)csv
Measured voltage waveform at 14.0 kV_pp and the corresponding total current...
Preview Download - Exploring the mechanisms leading to diffuse and filamentary modes - Fig. 10csv
Discharge current for the filamentary case as a function of the N2O...
Preview Download - Exploring the mechanisms leading to diffuse and filamentary modes - Fig. 11csv
Dissipated charge per filamentary discharge for different gas compositions...
Preview Download - Exploring the mechanisms leading to diffuse and filamentary modes - Fig. 14 (U)csv
Measured voltage waveform at 14.0 kV_pp (averaged over 1000 HV periods).
Preview Download - Exploring the mechanisms leading to diffuse and filamentary modes - Fig. 14acsv
Temporally resolved emission profiles for APTD cycles with different gas...
Preview Download - Exploring the mechanisms leading to diffuse and filamentary modes - Fig. 14bcsv
Temporally resolved emission profiles from hybrid cycles with a filament in...
Preview Download - Exploring the mechanisms leading to diffuse and filamentary modes - Fig. 14ccsv
Temporally resolved emission profiles from hybrid cycles with a filament in...
Preview Download - Exploring the mechanisms leading to diffuse and filamentary modes - Fig. 15csv
Modelling results for applied voltage, gap voltage, current density,...
Preview Download - Exploring the mechanisms leading to diffuse and filamentary modes - Fig. 16csv
Modelling results for spatially averaged densities and dominant gain/loss...
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