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Найдено документов в текущей БД: 76

    On the Boussinesq approximation in the problems of convection induced by high frequency vibration
[Текст] : статья / И.И. Рыжков // J. of Siberian Federal University. Mathematics & Physics. - 2010. - №3(4). - С. 433-449



Доп.точки доступа:
Gaponenko, Y.A.; Гапоненко, Юрий Анатольевич; Рыжков, Илья Игоревич

    Deep Solar Activity Minimum 2007-2009: Solar Wind Properties and Major Effects on the Terrestrial Magnetosphere
/ C. J. Farrugia [et al.] // Sol. Phys. - 2012. - Vol. 281, Is. 1. - pp. 461-489, DOI 10.1007/s11207-012-0119-1. - Cited References: 53 . - 29. - ISSN 0038-0938
РУБ Astronomy & Astrophysics

Аннотация: We discuss the temporal variations and frequency distributions of solar wind and interplanetary magnetic field parameters during the solar minimum of 2007-2009 from measurements returned by the IMPACT and PLASTIC instruments on STEREO-A. We find that the density and total field strength were significantly weaker than in the previous minimum. The Alfv,n Mach number was higher than typical. This reflects the weakness of magnetohydrodynamic (MHD) forces, and has a direct effect on the solar wind-magnetosphere interactions. We then discuss two major aspects that this weak solar activity had on the magnetosphere, using data from Wind and ground-based observations: i) the dayside contribution to the cross-polar cap potential (CPCP), and ii) the shapes of the magnetopause and bow shock. For i) we find a low interplanetary electric field of 1.3 +/- 0.9 mV m(-1) and a CPCP of 37.3 +/- 20.2 kV. The auroral activity is closely correlated to the prevalent stream-stream interactions. We suggest that the Alfven wave trains in the fast streams and Kelvin-Helmholtz instability were the predominant agents mediating the transfer of solar wind momentum and energy to the magnetosphere during this three-year period. For ii) we determine 328 magnetopause and 271 bow shock crossings made by Geotail, Cluster 1, and the THEMIS B and C spacecraft during a three-month interval when the daily averages of the magnetic and kinetic energy densities attained their lowest value during the three years under survey. We use the same numerical approach as in Fairfield's (J. Geophys. Res. 76, 7600, 1971) empirical model and compare our findings with three magnetopause models. The stand-off distance of the subsolar magnetopause and bow shock were 11.8 R-E and 14.35 R-E, respectively. When comparing with Fairfield's (1971) classic result, we find that the subsolar magnetosheath is thinner by similar to 1 R-E. This is mainly due to the low dynamic pressure which results in a sunward shift of the magnetopause. The magnetopause is more flared than in Fairfield's model. By contrast the bow shock is less flared, and the latter is the result of weaker MHD forces.

Полный текст


Доп.точки доступа:
Farrugia, C.J.; Harris, B.; Leitner, M.; Mostl, C.; Galvin, A.B.; Simunac, K.D.C.; Torbert, R.B.; Temmer, M.B.; Veronig, A.M.; Erkaev, N.V.; Еркаев, Николай Васильевич; Szabo, A.; Ogilvie, K.W.; Luhmann, J.G.; Osherovich, V.A.

    Scaling of the inner electron diffusion region in collisionless magnetic reconnection
/ A. Divin [et al.] // J. Geophys. Res-Space Phys. - 2012. - Vol. 117. - Ст. A06217, DOI 10.1029/2011JA017464. - Cited References: 43. - The present work is supported partially by the Onderzoekfonds KU Leuven (Research Fund KU Leuven), by the NASA MMS grant NNX08AO84G and by the European Commission's Seventh Framework Programme (FP7/2007-2013) under the grant agreement 263340 (SWIFF project, www. swiff. eu) and 269198 - Geoplasmas (Marie Curie International Research Staff Exchange Scheme). Additional support is provided by RFBR grants 09-05-91000-ANF-a, 12-05-00152-a and 12-05-00918-a, Austrian Science Fund project T193-N16 and by SPSU grants 11.38.47.2011 and 11.38.84.2012. The simulations were conducted on the resources of the Vlaams Supercomputer Centrum (VSC) at the Katholieke Universiteit Leuven. The authors wish to thank the reviewers for their comments that helped to improve the manuscript. . - ISSN 2169-9380
РУБ Astronomy & Astrophysics

Аннотация: The Sweet-Parker analysis of the inner electron diffusion region of collisionless magnetic reconnection is presented. The study includes charged particles motion near the X-line and an appropriate approximation of the off-diagonal term for the electron pressure tensor. The obtained scaling shows that the width of the inner electron diffusion region is equal to the electron inertial length, and that electrons are accelerated up to the electron Alfven velocity in X-line direction. The estimated effective plasma conductivity is based on the electron gyrofrequency rather than the binary collision frequency, and gives the extreme (minimal) value of the plasma conductivity similar to Bohm diffusion. The scaling properties are verified by means of Particle-in-Cell simulations. An ad hoc parameter needs to be introduced to the scaling relations in order to better match the theory and simulations.


Доп.точки доступа:
Divin, A.; Lapenta, G.; Markidis, S.; Semenov, V.S.; Erkaev, N.V.; Еркаев, Николай Васильевич; Korovinskiy, D.B.; Biernat, H.K.

    Current sheet oscillations in the magnetic filament approach
/ N.V. Erkaev, V.S. Semenov, H.K. Biernat // Phys. Plasmas. - 2012. - Vol. 19, Is. 6. - Ст. 62905, DOI 10.1063/1.4725506. - Cited References: 22. - This work is supported by RFBR Grants Nos. 12-05-00152-a and 12-05-00918-a, and also by St. Petersburg University grant. V. S. S. and H. K. B. are supported from the FP7 Programme under Grant No. 269198-Geoplasmas (Marie Curie Exchange Scheme). Additional support is due to the Austrian "Fonds zur Forderung der wissenschaftlichen Forschung" under Project I 193-N16 and the "Verwaltungsstelle fur Auslandsbeziehungen" of the Austrian Academy of Sciences. . - ISSN 1070-664X
РУБ Physics, Fluids & Plasmas

Аннотация: Magnetic filament approach is applied for modeling of nonlinear "kink"-like flapping oscillations of thin magnetic flux tubes in the Earth's magnetotail current sheet. A discrete approximation for the magnetic flux tube was derived on a basis of the Hamiltonian formulation of the problem. The obtained system of ordinary differential equations was integrated by method of Rosenbrock, which is suitable for stiff equations. The two-dimensional exact Kan's solution of the Vlasov equations was used to set the background equilibrium conditions for magnetic field and plasma. Boundary conditions for the magnetic filament were found to be dependent on the ratio of the ionospheric conductivity and the Alfven conductivity of the magnetic tube. It was shown that an enhancement of this ratio leads to the corresponding increase of the frequency of the flapping oscillations. For some special case of boundary conditions, when the magnetic perturbations vanish at the boundaries, the calculated frequency of the "kink"-like flapping oscillations is rather close to that predicted by the "double gradient" analytical model. For others cases, the obtained frequency of the flapping oscillations is somewhat larger than that from the "double gradient" theory. The frequency of the nonlinear flapping oscillations was found to be a decreasing function of the amplitude. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4725506]


Доп.точки доступа:
Erkaev, N.V.; Еркаев, Николай Васильевич; Semenov, V.S.; Biernat, H.K.

    Analysis of rotational motion of material microstructure particles by equations of the Cosserat elasticity theory
[Text] / O.V. Sadovskaya, V.M. Sadovskii // Acoust. Phys. - 2010. - Vol. 56, Is. 6. - P942-950, DOI 10.1134/S1063771010060199. - Cited References: 19. - This study was supported by the Russian Foundation for Basic Research (project no. 08-01-00148), Complex Fundamental Research Program no. 2 of the Presidium of the Russian Academy of Sciences, and Siberian Division of the Russian Academy of Sciences (Interdisciplinary Integration Project no. 40). . - 9. - ISSN 1063-7710
РУБ Acoustics
Рубрики:
WAVES
   PROPAGATION

Аннотация: Oscillatory processes in media with microstructure under the action of concentrated impulse and time-periodic perturbations are analyzed within the Cosserat elasticity theory. According to the results of computations, such media are characterized by a resonance frequency equal to the frequency of natural oscillations of particle rotational motion. This frequency is a phenomenological parameter of a material. It was established that the oscillatory rotation of particles changes for monotone rotational motion with increasing intensity of shear strains.


Доп.точки доступа:
Sadovskaya, O.V.; Садовская, Оксана Викторовна; Sadovskii, V.M.; Садовский, Владимир Михайлович

    Kinetic Alfven wave instability in a Lorentzian dusty magnetoplasma
[Text] / N. Rubab [et al.] // Phys. Plasmas. - 2010. - Vol. 17, Is. 10. - Ст. 103704, DOI 10.1063/1.3491336. - Cited References: 54. - This work is funded by the Higher Education Commission of Pakistan under the HEC-Overseas scholarship program Grant No. Ref: 1-1/PM OS /Phase-II/Batch-I/Austria/2007/. Part of this work was done while N. V. Erkaev was at the Space Research Institute of the Austrian Academy of Sciences in Graz. This work is also supported due to the RFBR Grant No. 09-05-91000-ANF-a. Further support is due to the "Austrian Fonds zur Forderung der Wissenschaftlichen Forschung" under Grant No. P20145-N16. . - ISSN 1070-664X
РУБ Physics, Fluids & Plasmas

Аннотация: This study presents a theoretical approach to analyze the influence of kappa distributed streaming ions and magnetized electrons on the plasma wave propagation in the presence of dust by employing two-potential theory. In particular, analytical expressions under certain conditions are derived for various modes of propagation comprising of kinetic Alfven wave streaming instability, two stream instability, and dust acoustic and whistler waves. A dispersion relation for kinetic Alfven-like streaming instability has been derived. The effects of dust particles and Lorentzian index on the growth rates and the threshold streaming velocity for the excitation of the instability are examined. The streaming velocity is observed to be destabilizing for slow motion and stabilizing for fast streaming motions. It is also observed that the presence of magnetic field and superthermal particles hinders the growth rate of instability. Possible applications to various space and astrophysical situations are discussed. (C) 2010 American Institute of Physics. [doi:10.1063/1.3491336]


Доп.точки доступа:
Rubab, N.; Erkaev, N.V.; Еркаев, Николай Васильевич; Langmayr, D.; Biernat, H.K.

    Magnetosheath for almost-aligned solar wind magnetic field and flow vectors: Wind observations across the dawnside magnetosheath at X =-12 Re
[Text] / C.J. Farrugia [et al.] // J. Geophys. Res-Space Phys. - 2010. - Vol. 115. - Ст. A08227, DOI 10.1029/2009JA015128. - Cited References: 34. - The authors would like to thank David Burgess for helpful discussions. Part of this work was done when NVE was on a research visit to the Space Science Center of the University of New Hampshire, USA. This work is supported by NASA grants NNX08AD11G and NNG06GD41G, and also by RFBR grants 07-05-00135, 09-05-91000-ANF_a and by Program 16 of RAS. R. P. Lin has been supported in part by NASA grant NNX08AE34G at UC Berkeley, and the WCU grant (R31-10016) funded by the Korean Ministry of Education, Science and Technology. We thank D. J. McComas and H. J. Singer for the ACE plasma data and GOES magnetic field data, respectively, obtained through NASA cdaweb site. . - ISSN 0148-0227
РУБ Astronomy & Astrophysics

Аннотация: While there are many approximations describing the flow of the solar wind past the magnetosphere in the magnetosheath, the case of perfectly aligned (parallel or antiparallel) interplanetary magnetic field (IMF) and solar wind flow vectors can be treated exactly in a magnetohydrodynamic (MHD) approach. In this work we examine a case of nearly-opposed (to within 15) interplanetary field and flow vectors, which occurred on October 24-25, 2001 during passage of the last interplanetary coronal mass ejection in an ejecta merger. Interplanetary data are from the ACE spacecraft. Simultaneously Wind was crossing the near-Earth (X similar to -13 Re) geomagnetic tail and subsequently made an approximately 5-hour-long magnetosheath crossing close to the ecliptic plane (Z = -0.7 Re). Geomagnetic activity was returning steadily to quiet, "ground" conditions. We first compare the predictions of the Spreiter and Rizzi theory with the Wind magnetosheath observations and find fair agreement, in particular as regards the proportionality of the magnetic field strength and the product of the plasma density and bulk speed. We then carry out a small-perturbation analysis of the Spreiter and Rizzi solution to account for the small IMF components perpendicular to the flow vector. The resulting expression is compared to the time series of the observations and satisfactory agreement is obtained. We also present and discuss observations in the dawnside boundary layer of pulsed, high-speed (v similar to 600 km/s) flows exceeding the solar wind flow speeds. We examine various generating mechanisms and suggest that the most likely cause is a wave of frequency 3.2 mHz excited at the inner edge of the boundary layer by the Kelvin-Helmholtz instability.


Доп.точки доступа:
Farrugia, C.J.; Erkaev, N.V.; Еркаев, Николай Васильевич; Torbert, R.B.; Biernat, H.K.; Gratton, F.T.; Szabo, A.; Kucharek, H.; Matsui, H.; Lin, R.P.; Ogilvie, K.W.; Lepping, R.P.; Smith, C.W.

    Resonant properties of moment Cosserat continuum
[Text] / M.P. Varygina, O.V. Sadovskaya, V.M. Sadovskii // J. Appl. Mech. Tech. Phys. - 2010. - Vol. 51, Is. 3. - pp. 405-413, DOI 10.1007/s10808-010-0055-5. - Cited References: 9. - This work was supported by the Russian Foundation for Basic Research (Grant No. 08-01-00148), the Complex Program of Basic Research of the Presidium of the Russian Academy of Sciences No. 2 Intelligent information technologies, mathematical modeling, system analysis and automation, and the interdisciplinary Integration project of the Siberian Division of the Russian Academy of Sciences No. 40. . - ISSN 0021-8944
РУБ Mechanics + Physics, Applied

Кл.слова (ненормированные):
elasticity -- moment medium -- parallel algorithm -- resonant spectrum

Аннотация: Using highly effective parallel calculations, it is shown that in a moment elastic medium, there is a resonant frequency which corresponds to the eigenfrequency of rotational motion of particles and does not depend on the size of the region studied.


Доп.точки доступа:
Varygina, M.P.; Варыгина, Мария Петровна; Sadovskaya, O.V.; Садовская, Оксана Викторовна; Sadovskii, V.M.; Садовский, Владимир Михайлович

    Effects of vibrations on dynamics of miscible liquids
[Text] / Y. Gaponenko, V. Shevtsova // Acta Astronaut. - 2010. - Vol. 66, Is. 01.02.2013. - pp. 174-182, DOI 10.1016/j.actaastro.2009.05.019. - Cited References: 10 . - ISSN 0094-5765
РУБ Engineering, Aerospace
Рубрики:
GRAVITY
Кл.слова (ненормированные):
Mixing -- Vibration -- Interface -- Miscible fluid

Аннотация: We report on a numerical study of the mixing of two miscible fluids in gravitationally stable configuration. In the absence of external forces the diffusion process leads to the mixing of species. The aim of this study is to analyze the physical mechanism by which vibrations affect the mixing characteristic of two stratified miscible fluids. The translational periodic vibrations of a rigid cell filled with different mixtures of water-isopropanol are imposed. The vibrations with a constant frequency and amplitude are directed along the interface. In absence of gravity vibration-induced mass transport is incomparably faster than in diffusion regime. Our results highlight the strong interplay between gravity and vibrational impact, the relative weight of each effect is determined by ratio vibrational and classical Rayleigh numbers. (C) 2009 Elsevier Ltd. All rights reserved.


Доп.точки доступа:
Gaponenko, Y.; Гапоненко, Юрий Анатольевич; Shevtsova, V.

    Plasma formation on a metal surface under combined action of laser and microwave radiation
[Text] / A. P. Gavrilyuk, N. Y. Shaparev // Quantum Electron. - 2013. - Vol. 43, Is. 10. - P943-948, DOI 10.1070/QE2013v043n10ABEH015141. - Cited References: 18 . - ISSN 1063-7818
РУБ Engineering, Electrical & Electronic + Physics, Applied

Кл.слова (ненормированные):
laser radiation -- microwave radiation -- metal surface -- plasma formation

Аннотация: By means of numerical modelling of the combined effect of laser (1.06 mu m) and microwave (10(10)-10(13) s(-1)) radiation on the aluminium surface in vacuum it is shown that the additional action of microwave radiation with the frequency 10(12) s(-1) provides complete ionisation of the metal vapour (for the values of laser radiation duration and intensity used in the calculations), while in the absence of microwave radiation the vapour remains weakly ionised. The mathematical model used accounts for the processes, occurring in the condensed phase (heat conduction, melting), the evaporation and the kinetic processes in the resulting vapour.


Доп.точки доступа:
Shaparev, N.Ya.; Шапарев, Николай Якимович; Гаврилюк, Анатолий Петрович

    Classification of Symbol Sequences over Their Frequency Dictionaries: Towards the Connection between Structure and Natural Taxonomy
/ A.N. Gorban, T.G. Popova, M.G. Sadovsky // Open Systems and Information Dynamics. - 2000. - Vol. 7, Is. 1. - P1-17 . - ISSN 1230-1612

Аннотация: The classifications of bacterial 16S RNA sequences developed over the real and transformed frequency dictionaries have been studied. Two sequences are considered to be close, when their frequency dictionaries are close in Euclidean metrics. A procedure to transform a dictionary is proposed that makes clear some features of the information pattern of a symbol sequence. A comparative study of classifications developed over real frequency dictionaries vs. the transformed ones has been carried out. A correlation between information patterns of nucleotide sequences and taxonomy of the bearer of the sequence was found. The sites with high information value are found to be the main factors of the difference between the classes in a classification. The classification of nucleotide sequences developed over real frequency dictionaries of thickness 3 reveals the best correlation to a gender of bacteria. A set of sequences of the same gender is included entirely into one class, as a rule, and exclusions occur rarely. A hierarchical classification yields one or two taxonomy groups on each level of classification. An unexpectedly often, or unexpectedly rare occurrence of some sites within a sequence makes a basic difference between the structure patterns of the classes yielded; a number of those sites is not to large. Further investigations are necessary in order to campare the sites revealed with those determined due to other methodology.

Scopus,
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Доп.точки доступа:
Gorban, A.N.; Горбань, Александр Николаевич; Popova, T.G.; Попова Т.Г.; Sadovsky, M.G.; Садовский, Михаил Георгиевич

    On the acoustic approximation of thermomechanical model of a liquid crystal
/ V. M. Sadovskii // Proceedings of XLI International Summer School–Conference APM 2013. - 2013. - P493-500

Аннотация: Based on the equations of dynamics of a structurally inhomogeneous elastic medium taking into account the rotational degrees of freedom of the particles of microstructure, a simplified mathematical model is worked out for description of the wave motion in nematic liquid crystals under the influence of weak mechanical and thermal perturbations. It is shown that in the case of plane strain the shear stress in such a medium satisfies the Klein–Gordon equation, describing the oscillatory nature of particles rotation. The results of numerical computations shows that the natural frequency of rotational motion of the particles, determined by this equation, is the resonance characteristic of a material, and it is independent of the size of a sample and of the loading conditions.

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Держатели документа:
ИВМ СО РАН : 660036, Красноярск, Академгородок, 50, стр.44

Доп.точки доступа:
Садовский, Владимир Михайлович

    Analysis of the Dispersion of Hydroacoustic Waves on the Basis of Viscoelastic Model
[Текст] : статья / V. M. Sadovskii, O. V. Sadovskaya, K. S. Svobodina // Journal of Siberian Federal University. Mathematics & Physics. - 2013. - Vol. 6, Iss. 3. - p. 342-348
   Перевод заглавия: Анализ дисперсии гидроакустических волн на основе модели вязкоупругой среды

Кл.слова (ненормированные):
viscoelastic medium -- Poynting–Thomson model -- hydroacoustic wave -- dispersion -- grid-characteristic method

Аннотация: On the basis of mathematical model of the Poynting–Thomson viscoelastic medium the effect of acoustic dispersion of water is described: the phase velocity of waves of terahertz frequency is doubled in comparison with the velocity of waves of sound range. Rheological parameters of the model are selected by means of the values of the velocities of propagation of slow and fast monochromatic waves. The system of equations of the dynamics of the Poynting–Thomson viscoelastic medium is reduced to the form, hyperbolic by Friedrichs. It guarantees the correctness of the Cauchy problem and boundary value problems with dissipative boundary conditions, and also allows to use the monotone grid-characteristic schemes for numerical solution of problems. In the framework of 1D model the computations of a transformation of hydroacoustic waves, generated by U-shaped impulse of pressure, were performed. Results of computations show a strong damping of the fast precursor as it passes the distance of hundred nanometers from the moment of entry and the emergence of stable profile of the slow wave at the mesolevel.

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Доп.точки доступа:
Sadovskaya, O.V.; Садовская, Оксана Викторовна; Svobodina, K.S.; Садовский, Владимир Михайлович

    Shear driven waves in the induced magnetosphere of Mars
[Text] / H. Gunell [et al.] // Plasma Phys. Control. Fusion. - 2008. - Vol. 50, Is. 7. - Ст. 74018, DOI 10.1088/0741-3335/50/7/074018. - Cited References: 27 . - ISSN 0741-3335
РУБ Physics, Fluids & Plasmas + Physics, Nuclear

Аннотация: We present measurements of oscillations in the electron density, ion density and ion velocity in the induced magnetosphere of Mars. The fundamental frequency of the oscillations is a few millihertz, but higher harmonics are present in the spectrum. The oscillations are observed in a region where there is a velocity shear in the plasma flow. The fundamental frequency is in agreement with computational results from an ideal-MHD model. An interpretation based on velocity-shear instabilities is described.


Доп.точки доступа:
Gunell, H.; Amerstorfer, U.V.; Nilsson, H.; Grima, C.; Koepke, M.; Franz, M.; Winningham, J.D.; Frahm, R.A.; Sauvaud, J.A.; Fedorov, A.; Erkaev, N.V.; Еркаев, Николай Васильевич; Biernat, H.K.; Holmstrom, M.; Lundin, R.; Barabash, S.

    Cluster observations showing the indication of the formation of a modified-two-stream instability in the geomagnetic tail
[Text] / S. . Muhbachler [et al.] // Adv. Space Res. - 2009. - Vol. 43, Is. 10. - P1588-1593, DOI 10.1016/j.asr.2009.01.012. - Cited References: 11. - For the provision of prime parameter data the authors thank the instrument teams of Cluster-CIS, -FGM, -PEACE, and -STAFF, in particular I. Danduras, E. Lucek, A. Fazakerley, and N. Cornilleau-Wehrlin. This work is partly supported by ESTEC Contract 18.201/04/NL/NR, by DLR Grant 50 OC 0003, by RFBR Grant 04-05-64088, by Programs 2.17 and 16.3 of RAS, and by Project PI7100-N08 of the Austrian Science Fund. . - ISSN 0273-1177
РУБ Astronomy & Astrophysics + Geosciences, Multidisciplinary + Meteorology & Atmospheric Sciences
Рубрики:
QUASI-PERPENDICULAR SHOCKS
Кл.слова (ненормированные):
Cluster -- Energetic particles -- Magnetotail -- Modified-two-stream instability

Аннотация: This study presents several observations of the Cluster spacecraft on September 24, 2003 around 15:10 UT, which show necessary prerequisites and consequences for the formation of the so-called modified-two-stream instability (MTSI). Theoretical studies suggest that the plasma is MTSI unstable if (1) a relative drift of electrons and ions is present, which exceeds the Alfven speed, and (2) this relative drift or current is in the cross-field direction. As consequences of the formation of a MTSI one expects to observe (1) a field-aligned electron beam, (2) heating of the plasma, and (3) an enhancement in the B-wave spectrum at frequencies in the range of the lower-hybrid-frequency (LHF). In this study we use prime parameter data of the CIS and PEACE instruments onboard the Cluster spacecraft to verify the drift velocities of ions and electrons, FGM data to calculate the expected LHF and Alfven velocity, and the direction of the current. The B-wave spectrum is recorded by the STAFF instrument of Cluster. Finally, a field aligned beam of electrons is observed by 3D measurements of the IES instrument of the RAPID unit. Observations are verified using a theoretical model showing the build-up of a MTSI under the given circumstances. (C) 2009 COSPAR. Published by Elsevier Ltd. All rights reserved.


Доп.точки доступа:
Muhbachler, S.; Langmayr, D.; Lui, ATY; Erkaev, N.V.; Еркаев, Николай Васильевич; Alexeev, I.V.; Daly, P.W.; Biernat, H.K.; ESTEC [18.201/04/NL/NR]; DLR [50 OC 0003]; RFBR [04-05-64088]; Austrian Science Fund [PI7100-N08]

    MHD model of the flapping motions in the magnetotail current sheet
[Text] / N. V. Erkaev [et al.] // J. Geophys. Res-Space Phys. - 2009. - Vol. 114. - Ст. A03206, DOI 10.1029/2008JA013728. - Cited References: 24. - We thank V. Sergeev for fruitful discussions and help in the preparation of the manuscript. This work is supported by RFBR grants N 07-05-00776-a, N 07-05-00135, by programs 2.16 and 16.3 of RAS, and by project P20341-N16 from the Austrian "Fonds zur Forderung der wissenschaftlichen Forschung,'' and also by project I.2/04 from "Osterreichischer Austauschdienst.'' . - ISSN 0148-0227
РУБ Astronomy & Astrophysics

Аннотация: A new kind of magnetohydrodynamic waves is analyzed for a current sheet in the presence of a small normal magnetic field component (B-z) varying along the sheet. For the initial undisturbed state, a simplified model of the current sheet is considered with a Harris-like current density distribution across the sheet. Within the framework of this model, an analytical solution is obtained for the flapping-type wave oscillations and instability, related to the gradient of the normal magnetic field component along the current sheet. The flapping wave frequency is found to be a function of the wave number, which has an asymptotic saturation for large wave numbers. This frequency is pure real in a stable situation for the magnetotail current sheet, when the Bz component increases toward Earth. The current sheet becomes unstable in some regions, where the Bz component decreases locally toward Earth. In the stable region, the "kink''-like wave oscillations are calculated for an initial Gaussian perturbation localized to the center of the current sheet. The flapping wave propagations are analyzed for two cases: (1) the initial perturbation is fixed, and (2) the source is moving toward Earth. In the last case, the Mach cone is obtained for the propagating flapping waves. The source for the flapping waves is associated with the fast plasma flow originated from the reconnection region.


Доп.точки доступа:
Erkaev, N.V.; Еркаев, Николай Васильевич; Semenov, V.S.; Kubyshkin, I.V.; Kubyshkina, M.V.; Biernat, H.K.; RFBR [N 07-05-00776-a, N 07-05-00135]; Austrian "Fonds zur Forderung der wissenschaftlichen Forschung,'' [P20341-N16]

    Mixing Under Vibrations in Reduced Gravity
[Text] : статья / Y. A. Gaponenko, V. Shevtsova // Microgravity Science and Technology. - 2008. - Vol. 20, Iss. 3-4 . - p. 307-311, DOI 10.1007/s12217-008-9075-7 . - ISSN 0938-0108

Аннотация: The aim of this study is to analyze the physical mechanism by which vibrations affect the mixing characteristic of two initially stratified miscible fluids. The translational periodic vibrations of a rigid cell filled with different mixtures (Sc = 7125) are considered. The vibrations with a constant frequency are imposed parallel to the initially planar interface. The ability of the applied vibrations to enhance the flow is examined. At the early stage after imposing the vibrations the Kelvin-Helmholtz instability is observed in absence and at low level of gravity. Later in time the system undergoes a transition to Rayleigh-Taylor instability. With increasing of gravity level the life-time of Kelvin-Helmholtz instability is decreased. We found the critical value of Gr above which this instability do not developed.

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Доп.точки доступа:
Shevtsova, V.; Гапоненко, Юрий Анатольевич

    Absorption and scattering of resonance laser radiation in ultracold optical dense plasma
[Text] / N. I. Kosarev, N. J. Shaparev // J. Phys. B-At. Mol. Opt. Phys. - 2008. - Vol. 41, Is. 23. - Ст. 235701, DOI 10.1088/0953-4075/41/23/235701. - Cited References: 12 . - ISSN 0953-4075
РУБ Optics + Physics, Atomic, Molecular & Chemical
Рубрики:
NEUTRAL PLASMAS
   TRAP

Аннотация: The problem of absorption and scattering of resonance laser radiation in ultracold optical dense plasma has been studied numerically. The frequency asymmetry of scattering and nonlinear absorption of light is predicted.


Доп.точки доступа:
Shaparev, N.Ya.; Шапарев, Николай Якимович

    On Dust Kinetic Alfven Waves and Streaming Instability in a Lorentzian Magnetoplasma
[Text] : статья / N. Rubab [et al.] // Proceedings of the 7th International Workshop on Planetary, Solar and Heliospheric Radio Emissions. - 2011. - p. 559-569

Аннотация: Dust kinetic Alfven waves (DKAW) instability with Kappa-distributed ions streaming effects have been examined rigorously in a uniform dusty magnetoplasma. A dispersion relation of low-frequency DKAW instability on the dust acoustic velocity branch is obtained in a low-beta Lorentzian plasma. It is found that nonthermality is more effective for dust kinetic Alfven waves in the perpendicular component having finite larmor radius effects. Lorentzian type charging currents are obtained with the aid of Vlasov theory. Effect of different dust parameters on the growth rates of instability are considered. Damping/instability due to dust charge fluctuation is found to be insensitive to the form of the distribution function for DKAW. Possible applications to dusty space plasmas are pointed out.

Полный текст на сайте издательства

Держатели документа:
ИВМ СО РАН : 660036, Красноярск, Академгородок, 50, стр.44

Доп.точки доступа:
Rubab, N.; Biernat, H.K.; Erkaev, N.V.; Еркаев, Николай Васильевич; Langmayr, D.; International Workshop on Planetary, Solar and Heliospheric Radio Emissions(7 ; September 15-17, 2010 ; Graz)

    Symmetries of equations for vibrational convection in binary mixture
[Text] : статья / I. V. Stepanova, I. I. Ryzhkov // Proceedings of 5-th Int. Workshop in Group analysis of differential equations and integrable system. - 2011. - p. 200-206 . - ISBN 978-9963-700-07-3

Аннотация: Dust kinetic Alfven waves (DKAW) instability with Kappa-distributed ions streaming effects have been examined rigorously in a uniform dusty magnetoplasma. A dispersion relation of low-frequency DKAW instability on the dust acoustic velocity branch is obtained in a low-beta Lorentzian plasma. It is found that nonthermality is more effective for dust kinetic Alfven waves in the perpendicular component having finite larmor radius effects. Lorentzian type charging currents are obtained with the aid of Vlasov theory. Effect of different dust parameters on the growth rates of instability are considered. Damping/instability due to dust charge fluctuation is found to be insensitive to the form of the distribution function for DKAW. Possible applications to dusty space plasmas are pointed out.

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Держатели документа:
ИВМ СО РАН : 660036, Красноярск, Академгородок, 50, стр.44

Доп.точки доступа:
Ryzhkov, I.I.; Рыжков, Илья Игоревич; Степанова, Ирина Владимировна; International Workshop in Group analysis of differential equations and integrable system(5 ; June 6–10, 2010 ; Protaras)