The influence of ripple current on characteristics of electric arc, stable in a cylindrical plasmatron channel.

The paper presents the results of experimental studies of nonstationary electric arc, stable partitioned in a cylindrical plasmatron channel. The experimental data obtained in the range of electric current I=50-200A, Im=1 -7 A, when the gas flow rate G=210-4 kg s-1, the frequency of alternating current f=300-20000Hz

Research of the influence of the geometry of the discharge chamber on the characteristics of the arc plasmatron.

© 2018 Institute of Physics Publishing. All rights reserved. This work shows the possibility of a significant effect on the characteristics of the plasma torch by changing the diameter of the arc chamber along its length

Characteristics of potential well for nondegenerate electronic gas in a equilibrium dusty plasma

Calculated of the potential well for electrons of the dust-electron plasma depending on the temperature, size of the dust particles, the distance between them and the kind of material of which they consist. The shape of the potential well is significantly different from the rectangular approximation. © Published under licence by IOP Publishing Ltd

Evaluation of the effectiveness of the use of arc plasma generator with distributed parameters for the deposition of functional coatings at low pressures.

The estimation of the mean mass enthalpy at the outlet of the plasmatron with distributed parameters. Non-equilibrium plasma at low pressures allows to combine the processes of plasma treatment and sputtering. It is necessary to consider the influence of electrode erosion

Calculation of distribution of potential near the surface of metal particle in the dust-electron thermal plasma

© Published under licence by IOP Publishing Ltd. We obtained the equation, which describes the distribution of the potential in an equilibrium dust-electron plasma taking into account parameters of the electron gas inside the dust particles. The inclusion of these parameters performed on the basis of the model of "solid- state plasma," considering the condensed particle system as the ion core and the free electron gas. The analytical expressions for the potential distributions in thermal equilibrium dust- electron plasma were obtained, using a number of simplifying assumptions. It is found that near the particle surface there is a large gradient of the electric potential and as a result the concentration offree electrons, i.e. electrons in the dust particle are located in a potential well. It is shown that the form of the potential barrier at the particle surface depends on the plasma temperature, particle size and concentration

Study of dust-electron plasma discharge on condition parallel of the velocity vector of the gas flow and electric field

Investigated non-independent electrical discharge in the longitudinal flow of dust-electron plasma. Found that the charge transfer in the discharge gap is mainly free electrons and positively charged dust particles. © Published under licence by IOP Publishing Ltd

Calculation of distribution of potential and electron concentration in the dust-electron thermal plasma with the axial geometry particles

© Published under licence by IOP Publishing Ltd. We obtained the equation, which describes the distribution of the potential and the electron density in an equilibrium dust-electron plasma taking into account parameters of the electron gas inside the axial geomtry dust particles. The inclusion of these parameters performed on the basis of the model of "solid-state plasma," considering the condensed particle system as the ion core and the free electron gas

A new method for the computation of eigenmodes in dielectric waveguides

A new method for the computation of eigenmodes in Isotropic cylindrical loss-free dielectric waveguides is proposed. Such waveguide is a cylindrical structure with the refractive index n not varied along the generatrix of cylinder. It is assumed that the waveguide is infinitely long and is in unbounded space with the constant index of refraction n∞ > 0. Besides, maxn > n7infin;. Eigenmodes are generator-free electromagnetic waves which satisfy the homogenous Maxwell equations. We consider surface waves. Original problem formulated in unbounded domain is reduced to a linear generalized spectral problem in the circle n containing the domain of the cross-section of the waveguide. To approximate obtained problem Finite Element Method is used. Our method allows computing of waveguides of different cross-sections such as circle, square, rectangle, three-circle, etc

A numerical method for finding dispersion curves and guided waves of optical waveguides

The original problem in an unbounded domain is reduced to a linear parametric eigenvalue problem in a circle, which is convenient for numerical solution. The examination of the solvability of this problem is based on the spectral theory of compact self-adjoint operators. The existence of guided waves is proved, and properties of the dispersion curves are investigated. An algorithm for the numerical solution of the problem based on the discretization of the equations using the finite element method is proposed. Numerical results are discussed. Copyright © 2005 by AMIK "Nauka/Interperiodica"

Stability analysis of gravity-driven infiltrating flow

[1] Stability analysis of gravity-driven unsaturated flow is examined for the general case of Darcian flow with a generalized nonequilibrium capillary pressure-saturation relation. With this nonequilibrium relation the governing equation is referred to as the nonequilibrium Richards equation (NERE). For the special case where the nonequilibrium vanishes, the NERE reduces to the Richards equation (RE), the conventional governing equation for describing unsaturated flow. A generalized linear stability analysis of the RE shows that this equation is unconditionally stable and therefore not able to produce gravity-driven unstable flows for infinitesimal perturbations to the flow field. A much stronger result of unconditional stability for the RE is derived using a nonlinear stability analysis applicable to the general case of heterogeneous porous media. For the general case of the NERE model, results of a linear stability analysis show that the NERE model is conditionally stable, with lower-frequency perturbations being unstable. A result of this analysis is that the nonmonotonicity of the pressure and saturation profile is a requisite condition for flow instability