In the present work, a single dielectric barrier discharge (SDBD)-based actuator is developed and experimentally tested by means of various diagnostic techniques. Flexible dielectric barriers and conductive paint electrodes are used, making the design concept applicable to surfaces of different aerodynamic profiles. A technical drawing of the actuator is given in detail. The plasma is sustained by audio frequency sinusoidal high voltage, while it is probed electrically and optically. The consumed electric power is measured, and the optical emission spectrum is recorded in the ultraviolet–near infrared (UV–NIR) range. High-resolution spectroscopy provides molecular rotational distributions, which are treated appropriately to evaluate the gas temperature. The plasma-induced flow field is spatiotemporally surveyed with pitot-like tube and schlieren imaging. Briefly, the actuator consumes a mean power less than 10 W and shows a fair stability over one day, the average temperature of the gas above its surface is close to 400 K, and the fluid speed rises to 4.5 m s⁻¹. A long, thin layer (less than 1.5 mm) of laminar flow is unveiled on the actuator surface. This thin layer is interfaced with an outspread turbulent flow field, which occupies a centimeter-scale area. Molecular nitrogen-positive ions appear to be part of the charged heavy species in the generated filamentary discharge, which can transfer energy and momentum to the surrounding air molecules.

The present report is devoted to the study of distinct ionization waves in terms of temporally-, spatially-, and wavelength-resolved analyses. The study is based on the technique of two-dimension fast imaging. However, appropriately selected ultraviolet to near infrared optical filters are employed to capture the propagation of specific species and digital image processing techniques are applied to explore the recorded snapshots. N₂(SPS), N 2 + (FNS), He I, OH(A–X), and O I, i.e., emissive neutral and ionic species, are investigated. On the other hand, the propagation of the NO _γ species is studied by means of laser-induced fluorescence spectroscopy, since the light intensity due to spontaneous emission of this species was not readily detectable. Digital image processing techniques are also applied for the NO _γ case. The crucial role of the above species in fields like plasma biomedicine and material processing is extensively recognized, and the present work: (i) provides gathered information on the propagation of these species within the atmospheric air; and (ii) introduces image processing algorithms to extract information which otherwise would remain hidden or uncorrelated with other plasma parameters. The present results unveil specific emission patterns due to the propagation of the N₂(SPS), N 2 + (FNS), He I, OH(A–X), and O I species. The intensity patterns consist of a first peak located in the vicinity of the reactor orifice, a second peak moving away from the reactor orifice, and a continuum which couples the two peaks. However, the detailed features of each pattern depend on the type of species considered. The fluorescence of the NO _γ species also suggests the division of the area downstream of the reactor orifice into two regions where distinct ionization-excitation effects take place. Propagation speeds of the species up to about 2 × 10⁵ m s⁻¹ were measured. Finally, qualitative correlation between the species propagation (as it is pronounced by the emission patterns) and the local electric field (as it was numerically calculated in a similar setup) is demonstrated.

The behavior of the electric field in Cold Atmospheric–Pressure Plasma jets (CAPP jets) is important in many applications related to fundamental science and engineering, since it provides crucial information related to the characteristics of plasma. To this end, this study is focused on the analytic computation of the electric field in a standard plasma reactor system (in the absence of any space charge), considering the two principal configurations of either one–electrode or two–electrodes around a dielectric tube. The latter is considered of minor contribution to the field calculation that embodies the working gas, being an assumption for the current research. Our analytical technique employs the cylindrical geometry, properly adjusted to the plasma jet system, whereas handy subdomains separate the area of electric activity. Henceforth, we adapt the classical Maxwell’s potential theory for the calculation of the electric field, wherein standard Laplace’s equations are solved, supplemented by the appropriate boundary conditions and the limiting conduct at the exit of the nozzle. The theoretical approach matches the expected physics and captures the corresponding essential features in a fully three–dimensional fashion via the derivation of closed–form expressions for the related electrostatic fields as infinite series expansions of cylindrical harmonic eigenfunctions. The feasibility of our method for both cases of the described experimental setup is eventually demonstrated by efficiently incorporating the necessary numerical implementation of the obtained formulae. The analytical model is benchmarked against reported numerical results, whereas discrepancies are commented and prospective work is discussed.

The scope of this paper is to present a comprehensive approach for simulating low-temperature atmospheric dielectric barrier discharge plasmas. The proposed methodology categorizes the primary physical phenomena: (i) discharge dynamics, (ii) ionic motion, and (iii) fluid flow, according to their respective time scales and simulates each independently. This allows for the use of distinct solution procedures tailored to each of the three stages of the problem. Such separation offers significant flexibility in choosing appropriate models and numerical schemes for each stage, enabling the simulation of complex geometries and large-scale applications without the excessive computational costs associated with a monolithic approach. As a case study, we apply the proposed algorithm to the surface dielectric barrier discharge plasma actuator for flow control, which is powered by alternating high voltages. The algorithm successfully described the actuator’s behavior while maintaining low computational cost. Additionally, a parametric study is conducted to examine the effect of key input parameters on the generated electrohydrodynamic force and the resulting velocity. Finally, an overall assessment of the three-stage model is provided, highlighting its efficiency and accuracy.