V. A. Yamshchikov

On the possibility of generating volume dielectric barrier discharge in air at atmospheric pressure

A homogeneous volume dielectric barrier discharge (DBD) in air at atmospheric pressure and natural humidity has been obtained. Conditions ensuring generation of a homogeneous DBD are described. It is shown that a determining influence on the homogeneity of DBD is produced by the rate of electric field strength growth in the discharge gap.

Electrohydrodynamic effect resulting from high-frequency barrier discharge in gas

The formation of an electrohydrodynamic flow in atmospheric air by using a high-frequency barrier discharge distributed over the dielectric surface is investigated. The influence of variations in parameters of a fully solid-state pulse generator (with a peak voltage of 0–12 kV, a tunable repetition rate of 10–25 kHz, and a pulse duration of 7 μs) on the current of plasma ion emitter and velocity characteristics of airflow is considered.

Formation of nanostructures during laser-induced melting of solid surfaces

In recent years, nanostructures in solids have begun to receive more attention from researchers as important objects having very promising applications in various fields of science and technology. Ordered and disordered ensembles of nanoparticles represent new artificial materials with a broad range of applications due to their unique properties. The nanostructured surfaces improve the electrical, thermal, and electron-emission properties of materials and lead to better compatibility of tissues with implants used in orthopedics and dentistry. They also find application in selective nanocatalysis, microelectronics, nanophotonics, spectroscopy, and high-power optics; ensure superhigh data recording density; and are used in developing light-emitting silicon-base devices. This implies a need for developing the physical foundations of new effective methods for the formation of two- and three-dimensional structures with characteristic sizes less than one micrometer both at the surface and in the bulk of solids and for studying the mechanisms of nanostructure formation, which can be of various natures. In this study, the possibility of forming nanostructures at solid surfaces by laser pulses leading to the melting of the material surface is evaluated. The action of a laser pulse with a certain energy density and duration on a solid surface can lead to the melting of the surface layer. Let us consider the process of its solidification due to subsequent heat removal in the depth of the solid phase. In this case, the liquid turns out to be in the supercooled state and a considerable temperature difference across the liquid‐solid interface is established. Depending on the degree of supercooling, the subsequent nucleation of the crystal phase can have either a fluctuational [1] or a spontaneous [2] character (Fig. 1). The variation of the thermodynamic potential during the formation of a new phase center (nucleus) consisting of n atoms can be described as follows:

Formation and growth of nanostructures on the surface of solids melted by laser pulses

The possibility of forming nanostructures on the surface of solids by the action of nanosecond laser pulses causing the material to melt has been shown both theoretically and experimentally. The dependence that the characteristic sizes of the surface nanostructures have on the energy of the laser beam and duration is established. Experimental results on samples of various materials obtained by direct laser nano-structuring using an ArF laser and images of titanium samples with surface nanostructures are presented.

Analysis of electrode system for generation of high-power electrodynamic flow

A high-power electrodynamic flow in atmospheric air is numerically simulated and experimentally studied. An electrode system consisting of a cylindrical plasma emitter and a plane metal grid collector of ions is used to generate a flow with a speed of 2 m/s and a volume rate of 15 L/s.

Simulation of Intense Electrohydrodynamic Flow Based on Dielectric Barrier Discharge

This paper presents a numerical analysis of the intense EHD gas flow velocity distribution at atmospheric pressure. The system consists of a coaxial plasma emitter and a collector grid. The ion source is a dielectric barrier discharge distributed over the surface of the emitter. The computational results coincide with the experimental data which allow us to predict the maximum flow rate produced by the experimental setup.

A multidischarge actuator system for power electrohydrodynamic action on the boundary layer of aerohydrodynamic surfaces

We present the results of a study of a new multidischarge actuator system designed for active gas flow control on the basis of a three-electrode circuit with a shielding electrode, in which the role of an accelerating electrode is played by the solid equipotential sheath surface of the wing. The main parameters of the multidischarge actuator system and classical scheme of electrodes are compared—namely, the induced air flow velocity, average integral volume force, average consumed power, and energy efficiency coefficient calculated per unit length of the external electrode.

A powerful electrohydrodynamic flow generated by a high-frequency dielectric barrier discharge in a gas

Theoretical and experimental studies of an electrohydrodynamic flow induced by a high-frequency dielectric barrier discharge distributed over a dielectric surface in a gas have been conducted. Dependences of the ion current, the gas flow velocity, and the spatial distributions thereof on the parameters of the power supply of the plasma ion emitter and an external electric field determined by the collector grid voltage have been described.

New Circulation System of Laser Gas Mixtures

The electrohydrodynamic flow in air, being formed at issue of ions from plasma of the high-frequency barrier discharge is investigated. It is shown that velocity of a flow is proportional to intensity of electric field between the emitter and a collector of ions. All solid-state pulse generator with voltage of U f = 0-12 kV and pulse repetition rate of f = 10-25 kHz is applied to feed the plasma emitter. It is experimentally established that the increase in high voltage and frequency of the plasma emitter feeding leads to increase velocity of a gas flow. The circulation system with a gas flow rate more than 15 L s–1and velocity more than 1.6 m s–1 was proposed for electric-discharge lasers.