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## Mathematical Model of Wave Perturbations in the Solar Atmosphere near Resonance Frequencies

P. 19-22.

Analytically and numerically calculations according to the original effective algorithms for largescale

acoustic-gravity wave perturbations in the chromosphere from sources at the level of the photosphere are

analyzed. Limitations to the energy flux of acoustic-gravity waves from the photosphere through the

chromosphere are formulated. Structure of a narrow region with elevated pressure at the resonance altitude

where the horizontal phase wave velocity is equal to the sound velocity is examined.

### In book

Issue 52: Mathematics and Computers in Science and Engineering Series. , Seul : World Scientific and Engineering Academy and Society, 2015

Савина О.Н., Беспалов П.А,, Ашина П.Н., В кн. : Солнечная и солнечно-земная физика - 2019: Труды ХIII Всероссийской ежегодной конференции по физике Солнца. : СПб. : ООО "Издательство ВВМ", 2019. С. 345-348.

The characteristics of intrinsic acoustic-gravitational vibrations in a strongly inhomogeneous chromosphere are considered. The influence of the temperature gradient on the limiting frequency of acoustic vibrations of the atmosphere is investigated. It is shown that due to the minimum atmospheric temperature observed in the solar chromosphere, it is possible to propagate acoustic-gravitational waves at frequencies ...

Added: December 25, 2019

Bespalov P. A., Savina O. N., Письма в Астрономический журнал 2008 Т. 34 № 5 С. 378-386

The generalized Wiedemann-Franz law for a nonisothermal quasi-neutral plasma with developedion-acoustic turbulence and Coulomb collisions has been proven. The results obtained are used to explain the anomalously low thermal conductivity in the chromosphere-corona transition region of the solar atmosphere. Model temperature distributions in the lower corona and the transition region that correspond to well-known experimental ...

Added: December 12, 2012

Petrukhin N., Pelinovsky E., Batsyna E. K., Письма в Астрономический журнал 2012 Т. 38 № 6 С. 439-445

The possibility that vertical acoustic waves with frequencies lower than the cutoff frequency corresponding to the temperature minimum pass this minimum is investigated. It is shown that the averaged temperature profile in the solar atmosphere can be approximated by several so-called reflectionless profiles on which the acoustic waves propagate without internal reflection. The possibility of ...

Added: May 3, 2012

Bespalov P. A., Savina O. N., Письма в Астрономический журнал 2009 Т. 35 № 5 С. 382-388

Based on model calculations, we show that ion-acoustic oscillations can be excited by heat fluxes in a plasma. We discuss the probable effect of ion-acoustic oscillations on the formation of temperature gradients at critical heat fluxes. The local critical heat flux in the transition region of the solar atmosphere is close to the well-known experimental ...

Added: December 12, 2012

Olga N. Savina, Bespalov P., Acta Geophysica 2015 Vol. 63 No. 1 P. 319-328

An original model of atmospheric wave propagation from the ground sources to ionosphere in the atmosphere with a realistic high-altitude temperature profile is analyzed. Shaping of a narrow domain with elevated pressure in the resonance region where the horizontal phase wave velocity is equal to the sound velocity is examined theoretically within the framework of ...

Added: August 26, 2014

Savina O.N., Bespalov P.A., Central European Astrophysical Bulletin 2016 Vol. 40 No. 1 P. 1-8

Some new features of the acoustic-gravity wave propagation from the sources at the photospheric heights through a nonisothermic solar chromosphere are examined. Within the framework of the plane-layered model of the atmosphere some properties of the wave perturbations near the height at which the horizontal phase wave velocity coincides with the local sound velocity are ...

Added: January 30, 2017

O.N. Savina, Central European Astrophysical Bulletin 2015 Vol. 39 P. 83-90

Natural oscillations of the entire nonisothermal solar atmosphere are analysed. Such oscillations are probably related to the acoustic gravity wave. Analytical and numerical solutions describing acoustic gravity wave perturbations in the entire solar atmosphere are studied. Based on the model temperature profile, we find the spatio-temporal dependence for the linear acoustic gravity wave characteristics. The ...

Added: December 6, 2015

Savina O. N., Bespalov P. A., Central European Astrophysical Bulletin 2011 Vol. 35 No. 1 P. 83-91

Within the framework of model calculations the possibility of occurrence of the ion-acoustic oscillation instability in a plasma without current and particle fluxes, but with an anisotropic distribution function, which corresponds to heat flux is shown. The model distribution function was selected taking into account the medium conditions. The increment of ion-acoustic oscillation is investigated ...

Added: December 12, 2012

Bespalov P. A., O.N. Savina, Astronomy Letters 2015 Vol. 41 No. 10 P. 601-605

We discuss the connection of the formation and properties of solar atmosphere transition region
characterized by a steep electron temperature gradient with electrostatic turbulence, which provides a high
effective electron collision frequency and a low thermal conductivity of the medium. A simple dependence
of the noise electric field in the transition region on the effective collision frequency has ...

Added: September 30, 2015

Ruderman M. S., Pelinovsky E., Petrukhin N. et al., Solar Physics 2013 Vol. 286 No. 2 P. 417-426

Propagating kink waves are ubiquitously observed in solar magnetic wave guides. We consider the possibility that these waves propagate without reflection although there is some inhomogeneity. We briefly describe the general theory of non-reflective, one-dimensional wave propagation in inhomogeneous media. This theory is then applied to kink-wave propagation in coronal loops. We consider a coronal ...

Added: March 28, 2013

Sadykov V. M., Kosovichev A. G., Sharykin I.N. et al., Astrophysical Journal 2019 Vol. 871 No. 1, article id. 2 P. 1-13

We present a statistical study of chromospheric evaporation in solar flares using simultaneous observations by the RHESSI X-ray telescope and the Interface Region Imaging Spectrograph UV spectrograph. The results are compared with radiation hydrodynamic flare models from the F-CHROMA RADYN database. For each event, we study spatially resolved Doppler shifts of spectral lines formed in ...

Added: February 1, 2020

П.А. Беспалов, О.Н. Савина, Письма в Астрономический журнал 2015 Т. 41 № 10 С. 651-656

The connection of between the formation and properties of areas characterized by the sharp gradient of electron temperature, with electrostatic turbulence, providing high a high effective electrons collision frequency and a low thermal conductivity of medium, is discussed. Simple dependences for the thermal conductivity, effective collision frequency and noise electric fields are obtained. For ...

Added: June 4, 2015

Chumachenko E. N., Logashina I. V., Качество. Инновации. Образование 2010 № 11 С. 30-35

Researches are devoted to computer techniques and information technologies based on mathematical modeling of mechanical systems and technological processes of metal forming. Techniques are intended for improvement of quality of designing of new technological processes and ways of their improvement. ...

Added: April 12, 2012

Chumachenko E. N., Aksenov S. A., Logashina I. V., Металлург 2010 № 8 С. 34-37

The paper describes the method of finite element simulation of shape rolling process based on 2,5D techniques which is due to the number of simplifications, allows to increase the rate of calculation considerably (by comparison with 3D modeling). To verify this technique the comparison of model results with data obtained at the metallurgical plant Trinecke ...

Added: April 12, 2012

Zakhariev I., Aksenov S. A., Journal of Chemical Technology and Metallurgy 2017 Vol. 52 No. 5 P. 1002-1007

Free bulging process is an experimental technique which can be used to characterize a sheet material in conditions of biaxial tension during hot forming. Analytical and semi-analytical models of this process are usually based on the hypothesis offering certain relations between the geometrical characteristics of a bulge during forming. The paper presents an original relation ...

Added: December 11, 2016

Chumachenko E. N., Logashina I. V., Zakhariev I., Металлург 2016 № 4 С. 102-105

The paper is devoted to simulation, analysis and optimization of a forging technology for manufacturing of titanium sections of high-pressure apparatuses. Computer simulation of material forming during the forging was performed using finite element method. The punching force evolution was study as well as deformation uniformity of the product walls, fillability of the dies and ...

Added: May 17, 2016

Zakhariev I., Aksenov S. A., В кн. : Труды XV Всероссийской научно-технической конференции и школы молодых учёных, аспирантов и студентов АКТ-2014. : Воронеж : ООО Фирма "Элист", 2014. С. 32-38.

This work is devoted to the investigation of the thickness-height dependence of the freely molded dome. The series of simulations were produced by finite element method. The generalization of the simulation results allowed us to obtain an analytical thickness-height relation of the dome ...

Added: October 22, 2015

Savina O. N., Bespalov P. A., Central European Astrophysical Bulletin 2013 Vol. 37 No. 2 P. 507-512

Peculiarities of acoustic-gravity wave near the solar atmosphere transition region are analysed. An investigation is based on an original characteristic relation of waves in a two layers model with a temperature jump. Special attention is paid to an analysis of the properties of the surface waves, generated by the source of mass, which crosses the ...

Added: September 25, 2013

Puzino Y. A., Вестник Чувашского государственного педагогического университета им. И.Я. Яковлева. Серия: Механика предельного состояния 2014 № 22 С. 46-52

The increasing of the efficiency of technological modes of steel products manufacturing requires simulation of metal forming during hot deformation. To obtain correct results, one should set the correct initial and boundary conditions, including the mechanical properties of materials, which represent the dependence of the stress-strain and strain rate at maintained temperature.
In the experiments one ...

Added: January 19, 2015

Petrukhin N., Ruderman M. S., Shurgalina E. G., Monthly Notices of the Royal Astronomical Society 2018 Vol. 474 No. 2 P. 2289-2301

We study damping of phase-mixed Alfvén waves propagating in non-reflective axisymmetric magnetic plasma configurations. We derive the general equation describing the attenuation of the Alfvén wave amplitude. Then we applied the general theory to a particular case with the exponentially divergent magnetic field lines. The condition that the configuration is non-reflective determines the variation of ...

Added: February 6, 2018

Soloviova (Solovieva) T. I., Belov A. V., Системотехника: Системные проблемы надежности, качества и информационных технологий 2012 № 10

The aim and the features of master program “Smart laser navigation systems” in MIEM of NRU HSE are described. Participation of research and development institute “Polyus” named by M.F.Stelmakh in creation and fulfillment of the master program is considered as an approval of actuality of the suggested applied education concept for Russian renewed technologies. ...

Added: January 18, 2013

Puzino Y. A., , in : Innovative Information Technologies: Materials of the International scientific–practical conference. Part 2. * 2.: M. : HSE, 2014. P. 432-437.

This aim of this paper is the interpretation of the results of mechanical testing of materials to determine their properties under hot deformation. As an example, a simulation of rod stretching in superplasticity mode was considered. Comparing obtained data with the analytical solution was conducted. ...

Added: May 26, 2014

Zakhariev I., Aksenov S. A., Logashina I. V., Металлург 2016

The paper is oriented toward the problem of superplastic materials characterization using free bulging testing. This experimental technique allows one to study the material flow behavior in conditions of biaxial tension which is very close to the ones occurring during hot gas forming. The interpretation of the results is proposed to perform by inverse analysis ...

Added: June 19, 2016

Aksenov S. A., Chumachenko E. N., Logashina I. V. et al., Hutnické listy 2010 No. 4 P. 110-113

The technological process considered in the paper is a rolling of a round bar in roughing mill group, which consist of four passes. The computer simulation of the process shows that the local plastic deformations occurring in the material are extremely large, which may lead to the appearing of defects. The investigations performed, led to ...

Added: April 12, 2012