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LXCat is an open‐access platform (www.lxcat.net) for curating data needed for modeling the electron and ion components of technological plasmas. The data types presently supported on LXCat are scattering cross sections and swarm/transport parameters, ion‐neutral interaction potentials, and optical oscillator strengths. Twenty‐four databases contributed by different groups around the world can be accessed on LXCat. New contributors are welcome; the database contributors retain ownership and are responsible for the contents and maintenance of the individual databases. This article summarizes the present status of the project., Plasma Processes and Polymers, 14 (1-2), ISSN:1612-8850, ISSN:1612-8869

International audience

International audience

This paper presents a study of the development of a surface dielectric barrier discharge in air under conditions similar to those of plasma actuators for flow control. The study is based on results from a 2D fluid model of the discharge in air that provides the space and time evolution of the charged particle densities, electric field and surface charges. The electrohydrodynamic (EHD) force associated with the momentum transfer from charged particles to neutral molecules in the volume above the dielectric layer is also deduced from the model. Results show that the EHD force is important not only during the positive part of the sinusoidal voltage cycle (i.e. when the electrode on top of the dielectric layer plays the role of the anode) but also during the negative part of the cycle (cathode on top of the dielectric layer). During the positive part of the cycle, the EHD force is due to the formation of a positive ion cloud that is periodically interrupted by high current breakdown. The EHD force during the negative part of the cycle is due to the development of a negative ion cloud that continuously grows during the successive high frequency current pulses that form in this regime.

International audience; We report experimental results showing that singlet oxygen O2(a1Δg) can be efficiently produced at atmospheric pressure in a three-electrode microcathode sustained discharge (MCSD) configuration. This configuration consists of a microhollow cathode discharge (MHCD) acting as a plasma cathode to sustain a stable glow discharge between the MHCD and a third planar electrode placed at a distance of 8 mm. Experiments were performed in He/O2/NO mixtures. O2(a1Δg) number densities higher than 1016 cm-3 were measured in the MCSD afterglow at total flow rates up to 30 ln/mn, resulting in O2(a1Δg) fluxes above 10 millimole per hour (mmol/h).

The electrohydrodynamic force generated by surface dielectric barrier discharges is analyzed with a fluid mode under conditions where the electrode above the dielectric surface is the anode.. The calculated current is composed of successive large pulses associated with filamentary discharges spreading along the dielectric surface, separated by low current periods where the discharge is in a transient ``coronalike'' regime. The contribution of the corona discharges to the overall force is by far dominant. An important result is that the extension of the region above the surface where the electrohydrodynamic force is significant depends on the product of the dielectric layer capacitance and the rate of voltage increase (spatial extension is larger when this parameter is smaller), but that the total, integrated force is not very sensitive to these parameters.

Surface dielectric barrier discharges (DBDs) have been proposed as actuators for flow control. In this paper we discuss the basic mechanisms responsible for the electrohydrodynamic (EHD) force exerted by the discharge on the gas molecules. A two-dimensional fluid model of the DBD is used to describe the plasma dynamics, to understand the basic physics associated with the EHD force and to give some quantitative estimation of the force under simplified conditions. The results show that for ramp or sinusoidal voltage waveforms, the discharge consists of large amplitude short current pulses during which a filamentary plasma spreads along the surface, separated in time by long duration, low current discharge phases of a Townsend or corona type. The contribution of the low current phases to the total force exerted by the discharge on the gas is dominant because their duration is much longer than that of the current pulses and because the force takes place in a much larger volume. A description of the different discharge regimes and a parametric study of the EHD force as a function of voltage rise time and dielectric thickness is presented.