The sizes of dust particles capable of levitating in dust traps in striations in a glow discharge in all inert gases are quantitatively determined for the same discharge parameters. A more than twofold decrease in the particle size was established upon passing from the gas with the maximum ionization potential (He) to Xe. The dependence found in the experiment is interpreted from the point of view of the conditions of particle levitation. It is shown that in gases with a low ionization potential in the balance of forces, the ion drag force exceeds the force of gravity, while the absolute values of the forces decrease with decreasing particle size. The discovered effect can be used for fine trapping of dust particles in plasma traps.

Experimental study has been made of the ignition of a subcritical microwave discharge at pressures in the range 55–79 Torr with the initiation by pulsed laser radiation (58 mJ in a pulse). A rise of 36

This article devoted to the study of gas heating in the region of an electric interelectrode discharge. The dynamics of local heating is studied using numerical methods and experimentally using an interferometer. The research results make it possible to evaluate the change in the temperature distribution in the cross section of the discharge track, the dynamics of the maximum heating temperature and the size of the heated area.

This article devoted to the study of gas heating in the region of an electric interelectrode discharge. The dynamics of local heating is studied using numerical methods and experimentally using an interferometer. The research results make it possible to evaluate the change in the temperature distribution in the cross section of the discharge track, the dynamics of the maximum heating temperature and the size of the heated area. Keywords: pulsed interelectrode discharge, low-temperature plasma, gas heating.

An experimental and numerical study of interaction between an oblique shock wave and density inhomogeneity is done. The inhomogeneity is created by interelectrode spark discharge in the oncoming flow with a Mach number of 2. As a result of the experiment, we obtained gradient heat flux sensor data and took shadow photography of the process.

In this work we performed calibration of the gradient heat flux sensor made of bismuth single crystal. The value of the volt-watt sensitivity of the sensor is found and a data processing method based on the one-dimensional heat equation for a thin plate is presented. An experimental study of the heat flux on the frontal surface of the cylinder after a laser discharge was carried out. The data obtained as a result of the experiment were processed by the proposed method.

The results of a preliminary study of the interaction of supersonic gas-plasma flows created by a magneto-plasma compressor and a pulsed erosion plasma jet are presented. Stable initiation of the MPC discharge at atmospheric pressure was achieved for the first time. The advantage of using the coaxial arrangement of plasma jets sources for MPC discharge initiation is shown. A noticeable change in the shock wave front velocity and pressure (up to 20%), created during the MPC discharge and dispersed powders and liquid mixtures interaction, is discovered.

The gradient heat flux sensor made of a bismuth single crystal is calibrated. The volt–watt sensitivity of the sensor is determined and the method of data processing based on the 1D heat conduction equation for a thin plate is proposed. This method is tested on experimental data obtained for the initiation of a laser discharge in a calm atmosphere and in a supersonic gas flow.

The first 200 ns of an air pulsed interelectrode discharge are considered with gas dynamics taken into account. It is this initial stage that is of most importance for determination of the properties of the heating power released in the interelectrode gap. Data are presented on heating of the near-cathode and -anode layers and the gap by the moment when the transient stage in the development of the discharge ends. A spherical expanding shock wave is produced near the cathode.

A plasma channel (filament) formed in the electromagnetic field of microwave (MW) radiation shows promise for its application for off-body non-electrode modification of a gas flow (plasma aerodynamics) and in the plasma assisted combustion process. In these problems, the channel is considered as an object that converts the energy of electromagnetic radiation into gas heating. To estimate the total power absorbed in the plasma from above, simple formula is obtained. Numerical calculations in air in the pressure range P = 20-100 Torr based on a simplified 2D model using a fairly complete system of plasma-chemical reactions have shown that the total absorbed power is close to its estimate from above when the plasma channel develops.

The action of a magnetic field on the behavior of a bulk dust cluster formed in the strata of a glowing discharge has been studied. The cluster that consists of seven chains of particles and is a hexagonal cell in the horizontal cross-section has been studied. It has been found that the rotation of a dust cluster arises in nonzero magnetic field unlike the dusty structure containing many particles in the horizontal cross-section. Moreover, it has been found that the threshold behavior of the occurrence of rotation in the cluster is affected by the discharge current and plasma-forming gas pressure. The enhancement of the ionization inside a dust cluster is suggested as an interpretation. The radial ion flux that moves in the longitudinal magnetic field from the dusty structure to the discharge tube wall additionally twists the structure with the negative projection of an angular velocity on the magnetic induction vector.

The paper presents for the first time studies of dusty plasmas formed in a glow discharge in a region of a strongly inhomogeneous magnetic field. The inhomogeneity of the magnetic field is estimated as 0.2 T/cm. A steady dust trap has been detected. The geometric characteristics of the plasma-dust structure were determined; the angular velocity of rotation was measured in several sections perpendicular to the axis of the discharge tube. The mechanism of rotation of the plasma-dust structure is proposed, quantitative estimates are made that confirm the experimental data.

Представлено исследование воздействия магнитного поля на поведение объемного пылевого кластера, образованного в страте тлеющего разряда. Изучен кластер, состоящий из семи цепочек частиц и представляющий собой в горизонтальном сечении гексагональную ячейку. Обнаружено, что возникновение вращения пылевого кластера происходит в ненулевом магнитном поле в отличие от пылевой структуры, содержащей большее число частиц в горизонтальном сечении. Кроме того, обнаружено, что на пороговый характер возникновения вращения в кластере влияет разрядный ток и давление плазмаформирующего газа. В качестве интерпретации выдвинуто предположение об увеличении ионизации внутри пылевой структуры. Радиальный поток ионов, идущий в продольном магнитном поле из пылевой структуры к стенке разрядной трубки, дополнительно раскручивает структуру с отрицательной проекцией угловой скорости на вектор магнитной индукции. Ключевые слова: пылевая плазма, магнитное поле, тлеющий разряд, кластеры.

We study the dynamics of dust particles in a stratified glow discharge in inhomogeneous magnetic fields. Dust structures are formed in standing striations, in which traps for dust particles arise. When a magnetic field is applied, these structures begin to rotate. The observations were carried out in striations near the end of the solenoid, where the region of an inhomogeneous magnetic field begins. With an increase in the magnetic field, the dusty structure can be deformed. The rotation of a dusty structure in an inhomogeneous magnetic field has been studied in detail; it has its own peculiarities in comparison with rotation in a uniform field. We have considered the mechanisms of such rotation and estimated its velocity.

AbstractSelf-rotation (rotation about the center of mass) of dust particles in a magnetic field has been investigated. The angular velocity of self-rotation in a dust trap produced by an rf discharge has been measured for the first time. It has been discovered that the angular velocity is independent of magnetic induction up to 700 G in spite of the action of ion drag. In addition, the dependence of self-rotation velocity on gas pressure in the discharge when the particles are in the dust trap and on power deposited into the discharge has been measured for the first time. Experimental data correlate well with the developed model of dust particle self-rotation, which appears to maintain the stationary charge of the dust particle.

Self-rotation (rotation about the center of mass) of dust particles in a magnetic field has been investigated. The angular velocity of self-rotation in a dust trap produced by an rf discharge has been measured for the first time. It has been discovered that the angular velocity is independent of magnetic induction up to 700 G in spite of the action of ion drag. In addition, the dependence of self-rotation velocity on gas pressure in the discharge when the particles are in the dust trap and on power deposited into the discharge has been measured for the first time. Experimental data correlate well with the developed model of dust particle self-rotation, which appears to maintain the stationary charge of the dust particle.

Abstract A research of own rotation of single dust particle which is in a dust trap in the stratified glow discharge under imposed magnetic field is carried out. It is experimentally shown that in the scale of Debye length an action of azimuthal torque from the fluxes of ions and electrons is mutually compensated; an angular velocity of rotation of dusty particle remains invariable up to magnetic fields of 200 G. The found effect was given theoretical interpretation on a basis of consideration of ambipolar diffusion of positive ions and electrons to the particle surface.

In this paper, we present investigation of a method for converting a supersonic plasma axisymmetric jet, created by a Magneto-Plasma Compressor, into flat plasma layers with various thicknesses and electron concentration. This kind of plasma layer has comparatively homogeneous structure and may use for experimental modelling of interaction of X-band radiation with high-speed plasma flow. The results of experimental studies of the microwave radiation transition through these layers are presented. The analysis of the received results within the one-dimensional (1D) approximation is carried out and the plasma concentrations are calculated.

A special setup was designed and built at St. Petersburg State University for providing experimental research in flow dynamics of the of air-water mixtures in a pipeline. The test section of the setup allows simulating a wide range of flow regimes of a gas-liquid mixture. The parameters of the experimental setup are given; the initial test results are discussed.

The problem of reliable microwave communication through a plasma sheath has its origin from the beginning of space flights. During reentry of spacecraft, the plasma layer can interrupt the communication. At sufficiently high plasma density, the plasma layer either reflects or attenuates radio wave communications to and from the vehicle. In this work, we present a simple analytical one-dimensional algorithm to study the propagation of electromagnetic (EM) waves through a nonuniform plasma layer in a static nonuniform magnetic field. The experimental study of the EM wave transmission and reflection through plasma layer was carried out on the (i) microwave set and (ii) on the unit using a high-voltage pulsed discharge.