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A. A. Yushkanov

Publications and source records attributed to A. A. Yushkanov.

At least 55 records · Page 3Linked to original sources
arXiv2012

Transverse electric conductivity in quantum collisional plasma in Mermin approach

Formulas for transversal electric conductivity and dielectric permeability of quantum collisional plasma are deduced. The kinetic equation for a density matrix in relaxation approaching in momentum space is used. It is shown, that when Planck's constant tends to zero, these deduced formulas pass in classical expressions and when frequency of electron collision tends to zero (i.e. plasma passes in collisionless plasma), the deduced formulas pass in deduced earlier by Lindhard. It is shown also, that when the wave number tends to zero, quantum conductivity passes in the classical one. Graphic comparison of the deduced conductivity with Lindhard's conductivity and with classical conductivity is carry out.

math-ph↗
arXiv2012

Transverse electric conductivity in quantum degenerate collisional plasma in Mermin approach

Formulas for transverse conductance in quantum collisional plasma are deduced. The kinetic equation in momentum space in the relaxation approach is used. It is shown, that at Planck's constant tends to zero the derived formula transfers to the classical one. It is shown also, that when electron collision frequency tends to null (i.e. plasma becomes collisionless), the conductance formula transfers in the known formula inferred earlier by Lindhard.

physics.plasm-ph↗
arXiv2012

Transverse electric conductivity and dielectric function in quantum Maxwellian collisional plasma by Mermin approach

Formulas for transverse conductance in quantum Maxwellian collisional plasma are deduced. The kinetic Von Neumann equation in momentum space with collision integral in the relaxation form is used. It is shown, that at Planck's constant tends to zero the derived formula transfers to the classical one. It is shown also, that when values of dimensionless wave numbers are small, the conductance formula transfers in the known formula for classical Maxwellian plasmas.

physics.plasm-ph↗
arXiv2012

Transverse electric conductivity and dielectric function in quantum non-degenerate collisional plasma by Mermin approach

Formulas for transverse conductance in quantum non-degenerate collisional plasma are deduced. The kinetic equation in momentum space in the relaxation approach is used. It is shown, that at $\hbar\to 0$ the derived formula transfers to the classical one. It is shown also, that when values of dimensionless wave numbers are small, the conductance formula transfers in the known formula for classical non-degenerate plasmas.

physics.plasm-ph↗
arXiv2012

Transversal electric conductivity of quantum non-degenerate collisional plasmas

Formulas for calculation of transversal dielectric function and transversal electric conductivity in quantum non-degenerate collisional plasmas under arbitrary degree of degeneracy of the electron gas are received. The Wigner-Vlasov-Boltzmann kinetic equation with collision integral in BGK (Bhatnagar, Gross and Krook) form in coordinate space is used. Various special cases are investigated

math-ph↗
arXiv2012

Analytical solution of second Stokes problem of behaviour of rarefied gas with Cercignani boundary accomodation conditions

Analytical solution of second Stokes problem of behaviour of rarefied gas with Cercignani boundary accomodation conditions The second Stokes problem about behaviour of rarefied gas filling half-space is analytically solved. A plane, limiting half-space, makes harmonious fluctuations in the plane. The kinetic BGK-equation (Bhatnagar, Gross, Krook) is used. The boundary accomodation conditions of Cercignani of reflexion gaseous molecules from a wall are considered. Distribution function of the gaseous molecules is constructed. The velocity of gas in half-space is found, also its value direct at a wall is found. The force resistance operating from gas on border is found. Besides, the capacity of dissipation of the energy falling to unit of area of the fluctuating plate limiting gas is obtained.

math-ph↗
arXiv2012

The Second Stokes Problem with Specular - Diffusive Boundary Conditions in Kinetic Theory

The second Stokes problem with specular - diffusive boundary conditions of the kinetic theory is considered. The new method of the decision of the boundary problems of the kinetic theory is applied. The method allows to receive the decision with any degree of accuracy. At the basis of a method lays the idea of representation of a boundary condition on distribution function in the form of a source in the kinetic equation. By means of integrals Fourier the kinetic equation with a source is reduced to the integral equation of Fredholm type of the second kind. The decision is received in the form of Neumann's series.

math-ph↗
arXiv2012

The Kramers Problem for Quantum Fermi Gases with Velocity - Dependent Collision Frequency and Specular - Diffusive Boundary Conditions

The classical Kramers problem of the kinetic theory is solved. The Kramers problem about isothermal sliding for quantum Fermi gases is considered. Quantum gases with the velocity - dependent collision frequency are considered. Specular - diffusive boundary conditions are applied. Dependence of isothermal sliding on the resulted chemical potential is found out.

math-ph↗
arXiv2012

The Kramers Problem for Quantum Fermi Gases with Velocity--Dependent Collision Frequency and Diffusive Boundary Conditions

The classical Kramers problem of the kinetic theory is analytically solved. The Kramers problem about isothermal sliding for quantum Fermi gases is considered. Quantum gases with the velocity-dependent collision frequency are considered. Diffusive boundary conditions are applied. Dependence of isothermal sliding on the resulted chemical potential is found out.

math-ph↗
arXiv2011

Analytical Solution of Second Stokes Problem on Behavior of Gas over Oscillation Surface. Part III: Solving of Problem and Applications

The second Stokes problem about behaviour of the rarefied gas filling half-space is formulated. A plane, limiting half-space, makes harmonious oscillations in the plane. The kinetic equation with model integral of collisions in the form $ τ$ - model is used. The case of diffusive reflection of molecules of gas from a wall is considered. There are eigen solutions (continuous modes) the initial kinetic equation, corresponding to the continuous spectrum. Properties of dispersion function are studied. The discrete spectrum of this problem consisting of zeroes of dispersion function in complex plane is investigated. It is shown, that number of zero of dispersion function to equally doubled index of coefficient of the problem. The problem coefficient is understood as the relation of boundary values of dispersion function from above and from below on the real axis. Further there are eigen solutions (discrete modes) the initial kinetic equation, corresponding to the discrete spectrum. The general solution of the kinetic equation in the form of expansion by eigen solutions with the unknown coefficients corresponding to discrete and continuous spectra is worked out. In the present work the analytical solution of second Stokes problem is constructed. On the basis of the analytical solution velocity of gas in half-space is calculated. Also velocity of gas directly at oscillating boundary is calculated precisely. The force of a friction operating from gas on the oscillating plate is found, and also dissipation of energy of a plate is obtained.

math-ph↗
arXiv2011

Analytical Solution of Second Stokes Problem on Behavior of Gas over Oscillation Surface. Part II: Mathematical Apparatus for Solving of Problem

In the present work the mathematical apparatus necessary for solving of second Stokes problem is developed. Second Stokes problem is the problem about behavior of rarefied gas filling half-space. A plane, limiting half-space, makes harmonious oscillations in this plane. At the heart of the analytical decision the homogeneous Riemann boundary value problem lays. The decision of homogeneous Riemann problem is function, factorizing problem. Integral representations for factorizing function is deduced. With the help of factorizing function the factorization formula for dispersion function is proved. Zero of dispersion function are searched by means of the factorization formula of dispersion function.

math-ph↗
arXiv2011

Analytical solution of the second Stokes problem on behavior of gas over a oscillation surface. Part I: eigenvalues and eigensolutions

The second Stokes problem about behaviour of the rarefied gas filling half-space is formulated. A plane, limiting half-space, makes harmonious oscillations in the plane. The kinetic equation with modelling integral of collisions in the form tau-model is used. The case of diffusive reflection of molecules of gas from a wall is considered. There are eigen solutions (continuous modes) the initial kinetic equation, corresponding to the continuous spectrum. Properties of dispersion function are studied. The discrete spectrum of this problem consisting of zeroes of dispersion function in complex plane is investigated. It is shown, that number of zero of dispersion function to equally doubled index of coefficient of the problem. The problem coefficient is understood as the relation of boundary values of dispersion function from above and from below on the real axis. Further there are eigen solutions (discrete modes) the initial kinetic equation, corresponding to the discrete spectrum. The common solution of the kinetic equation in the form of expansion by eigensolutions with the unknown coefficients corresponding to discrete and continuous spectra is worked out.

math-ph↗
arXiv2011

Friedel-Type Oscillations in the Problem of Skin Effect in Degenerate Collisionless Plasma

It is shown that a Friedel type oscillations accompany skin effect in degenerate plasma of a metal. It was learnt earlier that Friedel oscillations take place under charge screening in quantum plasma. However the nature of Friedel oscillations is not in the quantum character of the plasma, but in the features of degenerate Fermi distribution, namely, in its sharp transformation into zero directly just the other side of the Fermi surface. This circumstance leads to the Frieldel-type oscillations under anomalous skin effect.

math-ph↗
arXiv2011

New method of solving of boundary problems in kinetic theory

The classical Kramers problem with specular -- diffuse boundary conditions of the kinetic theory is considered. On an example of Kramers problem the new method of the decision of the boundary problems of the kinetic theory is stated. The method allows to receive the decision with any degree of accuracy. At the basis of a method lays the idea of representation of a boundary condition on distribution function in the form of a source in the kinetic equation. By means of integrals Furier the kinetic equation with a source is reduced to the integral equation of Fredholm type of the second kind. The decision is received in the form of Neumann's series.

math-ph↗
arXiv2011

Oscillations of Degenerate Plasma in Layer with Specular - Accommodative Boundary Conditions

The linearized problem of plasma oscillations in layer (particularly, in thin films) in external longitudinal alternating electric field is solved analytically. Specular - accommodative boundary conditions of electron reflection from the plasma boundary are considered. Coefficients of continuous and discrete spectra of the problem are found, and electron distribution function on the plasma boundary and electric field are expressed in explicit form. Absorption of energy of electric field in layer is calculated.

math-ph↗
arXiv2011

Landau's Problem of Degenerate Plasma Oscillations in Slab with Specular Boundary Conditions

In the present paper the linearized problem of plasma oscillations in slab (particularly, thin films) in external longitudinal alternating electric field is solved analytically. Specular boundary conditions of electron reflection from the plasma boundary are considered. Coefficients of continuous and discrete spectra of the problem are found, and electron distribution function on the plasma boundary and electric field are expressed in explicit form. Absorption of energy of electric field in slab is calculated.

math-ph↗