Труды сотрудников ИВМ СО РАН

[Text] : статья / I.L. Arshukova, N.V. Erkaev, H.K. Biernat // International journal of geomagnetism and aeronomy. - 2002. - Vol. 3, № 1. - p. 27–34
Аннотация: This article deals with the magnetohydrodynamic instability of the high magnetic shear magnetopause, which is considered to be a thin layer with a constant curvature radius and plasma velocity shear. In our model, the magnetic field and plasma density are assumed to be piecewise constant in three regions: in the magnetosphere adjacent to the magnetopause, in the magnetosheath, and inside a thin layer associated with the magnetopause. The plasma parameters and the magnetic field are assumed to obey the ideal incompressible magnetohydrodynamics. A Fourier analysis is used to calculate small perturbations of magnetic field and plasma parameters near the magnetopause in a linear approximation. The instability growth rate is obtained as a function of the angle between the velocity vector and the geomagnetic field direction for different plasma bulk speeds, wave numbers and curvature radii. The resulting instability is a mixture of interchange and Kelvin-Helmholtz instabilities on a surface with a nonzero curvature. The instability growth rate is an increasing function of the tangential velocity component perpendicular to the magnetic field. On the other hand, the growth rate is a decreasing function of the velocity component along the magnetic field.

http://icm.krasn.ru/refextra.php?id=2427,
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Держатели документа:
ИВМ СО РАН : 660036, Красноярск, Академгородок, 50, стр.44

Доп.точки доступа:
Erkaev, N.V.; Еркаев, Николай Васильевич; Biernat, H.K.; Аршукова И.Л.

/ D.B. Korovinskiy [et al.] // J. Geophys. Res-Space Phys. - 2013. - Vol. 118, Is. 3. - P1146-1158, DOI 10.1002/jgra.50206. - Cited References: 39. - This work is supported by the Austrian Science Fund (FWF): I193-N16, by the Onderzoekfonds KU Leuven (Research Fund KU Leuven), by RFBR Grants 12-05-00918-a and 12-05-00152-a, and by SPSU Grants 11.38.47.2011 and 11.38.84.2012. The research has received funding also from the European Union Seventh Framework Programme [FP7/2007-2013] under grant agreement 269198-Geoplasmas (Marie Curie International Research Staff Exchange Scheme) and 218816 (SOTERIA project). The simulations were conducted on the resources of the Vlaams Supercomputer Centrum (VSC) at the Katholieke Universiteit Leuven. N.V.E., V.S.S. and D.B.K. thank also ISSI for hospitality and financial support. The authors thank reviewers for their comments, which gave us the substantial aid in preparing of this manuscript. . - 13. - ISSN 2169-9380РУБ Astronomy & Astrophysics

Аннотация: The paper presents the detailed numerical investigation of the "double-gradient mode," which is believed to be responsible for the magnetotail flapping oscillations-the fast vertical (normal to the layer) oscillations of the Earth's magnetotail plasma sheet with a quasiperiod similar to 100-200 s. The instability is studied using the magnetotail near-equilibrium configuration. For the first time, linear three-dimensional numerical analysis is complemented with full 3-D MHD simulations. It is known that the "double-gradient mode" has unstable solutions in the region of the tailward growth of the magnetic field component, normal to the current sheet. The unstable kink branch of the mode is the focus of our study. Linear MHD code results agree with the theory, and the growth rate is found to be close to the peak value, provided by the analytical estimates. Full 3-D simulations are initialized with the numerically relaxed magnetotail equilibrium, similar to the linear code initial condition. The calculations show that current layer with tailward gradient of the normal component of the magnetic field is unstable to wavelengths longer than the curvature radius of the field line. The segment of the current sheet with the earthward gradient of the normal component makes some stabilizing effect (the same effect is registered in the linearized MHD simulations) due to the minimum of the total pressure localized in the center of the sheet. The overall growth rate is close to the theoretical double-gradient estimate averaged over the computational domain.

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

[Text] : статья / V.V.Denisenko // Computational Research. - 2013. - Vol. 1, № 2. - p. 34 - 51DOI 10.13189/cr.2013.010203 . -
Аннотация: Conventional two dimensional model for electric fields in the Earth’s ionosphere is analyzed to estimate its error. The main difficulties arise due to asymmetry of the conductivity tensor. We use the energy method and small parameter expansion. To make it possible in spite of asymmetry of the tensor coefficients the problem is reduced to the problem of minimum of proper quadratic energy functional. The variational principle is stated and proved for the 3-D boundary value problem. The error of the 2-D approximation is analyzed in the case, when conductor occupies a flat layer 0 < z < z0 and is homogeneous in z direction, and the vector of magnetic field has only z component. The results of numerical simulation of the electric field penetration from ground to the Earth’s ionosphere with reduction of the 3-D model of the ionospheric conductor to the 2-D model are presented. Precision of such an approach is demonstrated.

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

Доп.точки доступа:
Денисенко, Валерий Васильевич

/ I. I. Ryzhkov // International Journal of Heat and Mass Transfer. - 2013. - Vol. 66. - pp. 461-471, DOI 10.1016/j.ijheatmasstransfer.2013.07.044 . - ISSN 0017-9310
Аннотация: A simple and efficient method for solving the extended Graetz problem with specified heat flux in a circular pipe for a multicomponent fluid with Soret and Dufour effects is proposed. With a help of linear transformation of temperature and concentrations, the mass transfer equation and boundary conditions for each component are reduced to the form, which is completely identical to the thermal Graetz problem. The case when only the Soret effect is relevant is studied separately. It is shown that the above-described reduction fails when thermal and solutal Peclet numbers are equal. An alternative method of solution is proposed in this case. Examples of heat and mass transfer in a circular pipe for low Peclet numbers in a model fluid and for high Peclet numbers in the water-alumina nanofluid are considered. The proposed method can be extended to a parallel plate channel as well as annular region between cylindrical pipes with specified heat flux. However, the method cannot be applied to problems, where the temperature is specified on the impermeable pipe wall. В© 2013 Elsevier Ltd. All rights reserved.

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Доп.точки доступа:
Ryzhkov, I.I.; Рыжков, Илья Игоревич

[Text] / A. Divin [et al.] // Phys. Plasmas. - 2010. - Vol. 17, Is. 12. - Ст. 122102, DOI 10.1063/1.3521576. - Cited References: 42. - The present work is supported partially by the Onderzoekfonds KU Leuven (Research Fund KU Leuven) and by the European Commission's Seventh Framework Programme (FP7/2007-2013) under grant Agreement No. 218816 (SOTERIA project, www.soteria- space.eu). Additional support is provided by RFBR (Grant No. 09-05-91000-ANF-a). V.S.S. thanks ISSI for hospitality and financial support. The simulations were conducted on the resources of the Vlaams Supercomputer Centrum (VSC) at the Katholieke Universiteit Leuven. . - ISSN 1070-664XРУБ Physics, Fluids & Plasmas

Аннотация: A new model of the electron pressure anisotropy in the electron diffusion region in collisionless magnetic reconnection is presented for the case of antiparallel configuration of magnetic fields. The plasma anisotropy is investigated as source of collisionless dissipation. By separating electrons in the vicinity of the neutral line into two broad classes of inflowing and accelerating populations, it is possible to derive a simple closure for the off-diagonal electron pressure component. The appearance of these two electron populations near the neutral line is responsible for the anisotropy and collisionless dissipation in the magnetic reconnection. Particle-in-cell simulations verify the proposed model, confirming first the presence of two particle populations and second the analytical results for the off-diagonal electron pressure component. Furthermore, test-particle calculations are performed to compare our approach with the model of electron pressure anisotropy in the inner electron diffusion region by Fujimoto and Sydora [Phys. Plasmas 16, 112309 (2009)]. (C) 2010 American Institute of Physics. [doi:10.1063/1.3521576]


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

[Text] / N.V. Erkaev, V.S. Semenov, H.K. Biernat // Phys. Plasmas. - 2010. - Vol. 17, Is. 6. - Ст. 60703, DOI 10.1063/1.3439687. - Cited References: 15. - This work is supported by RFBR (Grant Nos. N 07-05-00776-a and N 09-05-91000-ANF_a), and by Program No. 16 of RAS. Additional support is due to the Austrian "Fonds zur Forderung der wissenschaftlichen Forschung" under Project No. I 193-N16 and the "Verwaltungsstelle fur Auslandsbeziehungen" of the Austrian Academy of Sciences. . - ISSN 1070-664XРУБ Physics, Fluids & Plasmas

Аннотация: Hall magnetohydrodynamic model is investigated for current sheet flapping oscillations, which implies a gradient of the normal magnetic field component. For the initial undisturbed current sheet structure, the normal magnetic field component is assumed to have a weak linear variation. The profile of the electric current velocity is described by hyperbolic functions with a maximum at the center of the current sheet. In the framework of this model, eigenfrequencies are calculated as functions of the wave number for the "kink" and "sausage" flapping wave modes. Because of the Hall effects, the flapping eigenfrequency is larger for the waves propagating along the electric current, and it is smaller for the opposite wave propagation with respect to the current. The asymmetry of the flapping wave propagation, caused by Hall effects, is pronounced stronger for thinner current sheets. This is due to the Doppler effect related to the electric current velocity. (C) 2010 American Institute of Physics. [doi:10.1063/1.3439687]


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

[Text] : статья / S. Arcidiacono, J. Mantzaras, I. V. Karlin // Physical review E. - 2008. - Vol. 78. - Ст. 046711, DOI 10.1103/PhysRevE.78.046711 . - ISSN 1539-3755
Аннотация: A lattice Boltzmann model is developed to simulate finite-rate catalytic surface chemistry. Diffusive wall boundary conditions are established to account for catalytic reactions in multicomponent mixtures. Implementation of wall boundary conditions with chemical reactions is based on a general second-order accurate interpolation scheme. Results of lattice Boltzmann simulations for a four-component mixture with a global catalytic methane oxidation reaction in a straight channel are in excellent agreement with a finite volume Navier-Stokes solver in terms of both the flow field and species concentrations.

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

Доп.точки доступа:
Mantzaras, J.; Karlin, I.V.; Карлин, Илья Вениаминович

[Text] / N. V. Erkaev, V. S. Semenov, H. K. Biernat // Geophys. Res. Lett. - 2008. - Vol. 35, Is. 2. - Ст. L02111, DOI 10.1029/2007GL032277. - Cited References: 13 . - ISSN 0094-8276РУБ Geosciences, Multidisciplinary

Аннотация: A new kind of magnetohydrodynamic waves are analyzed for a current sheet in a presence of a small normal magnetic field component varying along the sheet. As a background, two simplified models of a current sheet are considered with a uniform and nonuniform current distributions in the current sheet. On a basis of these two models, the flapping-type waves are obtained which are related to a coexistence of two gradients of the tangential and normal magnetic field components along the normal and tangential directions with respect to the current sheet. A stable situation for the current sheet is associated with a positive result of the multiplication of the two magnetic gradients, and unstable ( wave growth) condition corresponds to a negative result of the product. In the stable region, the "kink''-like wave mode is interpreted as so called flapping waves observed in the Earth's magnetotail current sheet.


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

[Text] / N. V. Erkaev, V. S. Semenov, H. K. Biernat // Phys. Rev. Lett. - 2007. - Vol. 99, Is. 23. - Ст. 235003, DOI 10.1103/PhysRevLett.99.235003. - Cited References: 10 . - ISSN 0031-9007РУБ Physics, Multidisciplinary

Аннотация: A new kind of magnetohydrodynamic instability and waves are analyzed for a current sheet in the presence of a small normal magnetic field component varying along the sheet. These waves and instability are related to the existence of two gradients of the tangential (B(tau)) and normal (B(n)) magnetic field components along the normal (del(n)B(tau)) and tangential (del(tau)B(n)) directions with respect to the current sheet. The current sheet can be stable or unstable if the multiplication of two magnetic gradients is positive or negative. In the stable region, the kinklike wave mode is interpreted as so-called flapping waves observed in Earth's magnetotail current sheet. The kink wave group velocity estimated for the Earth's current sheet is of the order of a few tens of kilometers per second. This is in good agreement with the observations of the flapping motions of the magnetotail current sheet.


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

[Text] / D.Langmayr, N. V. Erkaev, H. K. Biernat // Planet Space Sci. - 2007. - Vol. 55, Is. 12. - P1804-1810, DOI 10.1016/j.pss.2007.01.017. - Cited References: 19 . - ISSN 0032-0633РУБ Astronomy & Astrophysics

Аннотация: This paper is devoted to the application of the modified two stream or cross current instability (MTST) to the interaction of the solar wind and Venus. Two scenarios are presented providing favorable conditions for the excitation of the instability. For the first scenario, the free energy source of the MTSI is a significant gradient drift of the solar wind protons near the subsolar ionopause. The corresponding growth rates and frequencies of the MTSI are calculated within a full electromagnetic approach for a two-component plasma. The driving source of the second considered scenario consists in the relative drift velocity between solar wind and planetary particles. For modelling this situation, the dispersion equation for a four-component plasma is solved numerically. (C) 2007 Elsevier Ltd. All rights reserved.


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

[Text] / N. V. Erkaev [et al.] // Astrophys. J. Suppl. Ser. - 2005. - Vol. 157, Is. 2. - P396-401, DOI 10.1086/427904. - Cited References: 48 . - ISSN 0067-0049РУБ Astronomy & Astrophysics

Аннотация: During the past years, more than 130 giant planets were discovered in extrasolar planetary systems. Because of the fact that the orbital distances are very close to their host stars, these planets are embedded in a dense stellar wind, which can pick up planetary ions. We model the stellar wind interaction of the short-periodic exoplanets OGLE-TR-56b and HD 209458b at their orbital distances of approximate to 0.023 AU and approximate to 0.045 AU, by calculating the Alfven Mach number and the magnetosonic Mach number in the stellar wind plasma flow. We then analyze the different plasma interaction regimes around the planetary obstacles, which appear for different stellar wind parameters. Our study shows that the stellar wind plasma parameters like temperature, interplanetary magnetic field, particle density, and velocity near planetary obstacles at orbital distances closer than 0.1-0.2 AU have conditions such that no bow shocks evolve. Our study shows also that these close-in exoplanets are in a submagnetosonic regime comparable to the magnetospheric plasma interaction of the inner satellites of Jupiter and Saturn. Furthermore, we compare the results achieved for both exoplanets with the Jupiter-class exoplanet HD 28185b at its orbital distance of approximate to 1.03 AU. Finally, we also discuss the behavior of the stellar wind plasma flow close to the planetary obstacles of two highly eccentric gas giants, namely, HD 108147b and HD 162020b. Because of their eccentric orbits, these two exoplanets periodically experience both regimes with and without a bow shock. Finally, we simulate the neutral gas density of HD 209458b with a Monte Carlo model. By using the plasma parameters obtained in our study we calculate the ion production and loss rate of H+ with a test particle model. Our simulations yield H+ loss rates for HD 209458b or similar giant exoplanets in orders of about 10(8)-10(9) g s(-1). These ion loss rates are at least 1 order of magnitude lower than the observed loss rate of evaporating neutral H atoms. Our study indicates, that similar gas giants at larger orbital distances have lower ion loss rates. Thus, the dominating component of particle loss of short-periodic Jupiter-class exoplanets will be neutral hydrogen.


Доп.точки доступа:
Erkaev, N.V.; Еркаев, Николай Васильевич; Penz, T.; Lammer, H.; Lichtenegger, H.I.M.; Biernat, H.K.; Wurz, P.; Griessmeier, J.M.; Weiss, W.W.

[Text] / I. L. Arshukova, N. V. Erkaev, H. K. Biernat // Phys. Plasmas. - 2002. - Vol. 9, Is. 2. - P401-408, DOI 10.1063/1.1432698. - Cited References: 15 . - ISSN 1070-664XРУБ Physics, Fluids & Plasmas

Аннотация: This article deals with the magnetohydrodynamic instability of a thin layer which is characterized by a high magnetic shear, a constant curvature radius, and a plasma velocity shear. The magnetic field and the plasma parameters are considered to be piecewise constant inside the layer and in the regions adjacent to the layer. The plasma parameters and the magnetic field are assumed to obey the ideal incompressible magnetohydrodynamics. Fourier analysis is used to calculate small perturbations of the magnetic field and plasma parameters near the layer in linear approximation. The instability growth rate is obtained as a function of different parameters: the magnetic shear angle, the velocity direction angle, the tangential plasma velocity, the layer thickness, the wave number, and the curvature radius. The resulting instability is a mixture of interchange and Kelvin-Helmholtz instabilities on a surface with nonzero curvature. For a fixed velocity shear and curvature radius, the instability growth has a maximum in the case of antiparallel magnetic fields (maximal magnetic shear). This growth rate is an increasing function of the tangential velocity component perpendicular to the magnetic field, and a decreasing function of the velocity component along the magnetic field. The instability is stronger for smaller curvature radius. (C) 2002 American Institute of Physics.


Доп.точки доступа:
Arshukova, I.L.; Erkaev, N.V.; Еркаев, Николай Васильевич; Biernat, H.K.

[Text] / D. F. Vogl [et al.] // Nonlinear Process Geophys. - 2001. - Vol. 8: 25th General Assembly of the European-Geophysical-Society (APR, 2000, NICE, FRANCE), Is. 3. - P167-174. - Cited References: 16 . - ISSN 1023-5809РУБ Geochemistry & Geophysics + Meteorology & Atmospheric Sciences

Аннотация: Taking into account the pressure anisotropy in the solar wind, we study the magnetic field and plasma parameters downstream of a fast shock, as functions of upstream parameters and downstream pressure anisotropy. In our theoretical approach, we model two cases: a) the perpendicular shock and b) the oblique shock. We use two threshold conditions of plasma instabilities as additional equations to bound the range of pressure anisotropy. The criterion of the mirror instability is used for pressure anisotropy P (perpendicular to)/P (parallel to) 1. Analogously, the criterion of the fire-hose instability is taken into account for pressure anisotropy P-perpendicular to/P-parallel to 1. We found that the variations of the parallel pressure, the parallel temperature, and the tangential component of the velocity are most sensitive to the pressure anisotropy downstream of the shock. Finally, we compare our theory with plasma and magnetic field parameters measured by the WIND spacecraft.


Доп.точки доступа:
Vogl, D.F.; Biernat, H.K.; Erkaev, N.V.; Еркаев, Николай Васильевич; Farrugia, C.J.; Muhlbachler, S.

[Text] / D. F. Vogl [et al.] // PLANETARY MAGNETOSPHERES. Ser. ADVANCES IN SPACE RESEARCH : ELSEVIER SCIENCE BV, 2001. - Vol. 28: D3 1/C3 3 Symposium of COSPAR Scientific Commission D held at the 33rd COSPAR Scientific Assembly (JUL, 2000, WARSAW, POLAND), Is. 6. - P851-856, DOI 10.1016/S0273-1177(01)00503-8. - Cited References: 12 . - ISBN 0273-1177РУБ Engineering, Aerospace + Astronomy & Astrophysics + Geosciences, Multidisciplinary + Meteorology & Atmospheric Sciences

Аннотация: In this paper we report on the variations of the magnetic field strength and the plasma parameters across a fast shock as functions of upstream Alfven Mach numbers and pressure anisotropy downstream of the shock. In our study we consider an oblique shock where the angle between the magnetic field vector and the normal vector upstream of the shock is chosen to be 45degrees. We further use two threshold conditions of plasma instabilities as additional equations to bound the range of the pressure anisotropy, p(perpendicular to)/p(\\), i.e., the criterion of the mirror instability and that of the fire-hose instability. We found that the variations of the parallel pressure, the parallel temperature, as well as the tangential component of the velocity are most sensitive to the pressure anisotropy downstream of the shock, whereas the variations of the plasma density, the normal velocity, the magnetic field strength, and perpendicular pressure and temperature with respect to the magnetic field show much less pronounced dependence on the anisotropy. (C) 2001 COSPAR. Published by Elsevier Science Ltd. All rights reserved.


Доп.точки доступа:
Vogl, D.F.; Erkaev, N.V.; Еркаев, Николай Васильевич; Biernat, H.K.; Muhlbachler, S.; Farrugia, C.J.

[Text] / N. V. Erkaev, C. J. Farrugia, H. K. Biernat // J. Geophys. Res-Space Phys. - 1999. - Vol. 104, Is. A4. - P6877-6887, DOI 10.1029/1998JA900134. - Cited References: 29 . - ISSN 0148-0227РУБ Astronomy & Astrophysics

Аннотация: We present a three-dimensional, one-fluid, steady state magnetohydrodynamic (MHD) model of magnetosheath flow near the subsolar line with unequal plasma pressures perpendicular (P-perpendicular to) and parallel (P-parallel to) to the magnetic field (P-perpendicular to P-parallel to) Aside from an assumption on the total pressure normal to the magnetopause, our analytical-numerical method is completely general and is an extension of our isotropic, "magnetic string" MHD model, which we describe in detail here. The MHD equations are closed by a relation between P-perpendicular to and P-parallel to as in the Bounded Anisotropy Model [Denton et al., 1994] corresponding to the threshold of the electromagnetic proton cyclotron wave instability. We take an IMF oriented perpendicular to the solar wind velocity. As boundary conditions, we have Rankine-Hugoniot relations at the bow shock and a no-flow condition at the magnetopause. We obtain steady state profiles of the magnetic field and plasma parameters for upstream sonic and Alfven Mach numbers equal to 10, and compare them with the isotropic case (P-parallel to = P-perpendicular to). Anisotropy slightly thickens the magnetosheath. In the anisotropic model, the density, the parallel and perpendicular temperatures, plasma pressures, and betas all decrease toward the magnetopause. Isotropic profiles lie between those of quantities perpendicular and parallel to the field. Anisotropy has considerable effect on the density profile, which lies below that in the isotropic limit throughout the magnetosheath. Density depletion results from stretching of magnetic field lines, which is caused by field-aligned plasma flow. Approaching the magnetopause, the tangential component of velocity parallel to the magnetic field decreases, while the tangential component perpendicular to the magnetic field increases. These are features characterizing a stagnation line flow at the magnetopause. The acceleration along the magnetic field is produced by the gradient of P-parallel to and the mirror force, which depends on anisotropy. They both make substantial contributions and are responsible for the changes we see;from isotropy. The acceleration perpendicular to magnetic field is also larger than in the case of isotropy and is caused by the gradient of total pressure, the magnetic strength, and the mirror force. In addition, acceleration in both directions is affected by the decreasing density.


Доп.точки доступа:
Erkaev, N.V.; Еркаев, Николай Васильевич; Farrugia, C.J.; Biernat, H.K.

[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 0148-0227РУБ 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]

[Text] / N. V. Erkaev [et al.] // Ann. Geophys. - 2009. - Vol. 27, Is. 1. - P417-425. - Cited References: 24. - We thank V. Sergeev for fruitful discussions and help in preparation of the manuscript. This work is supported by RFBR grants N07-05-00776-a, N 07-05-00135, by SFU grant N 10, 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 0992-7689РУБ Astronomy & Astrophysics + Geosciences, Multidisciplinary + Meteorology & Atmospheric Sciences

Аннотация: One-fluid ideal MHD model is applied for description of current sheet flapping disturbances appearing due to a gradient of the normal magnetic field component. The wave modes are studied which are associated to the flapping waves observed in the Earth's magnetotail current sheet. In a linear approximation, solutions are obtained for model profiles of the electric current and plasma densities across the current sheet, which are described by hyperbolic functions. The flapping eigenfrequency is found as a function of wave number. For the Earth's magnetotail conditions, the estimated wave group speed is of the order of a few tens kilometers per second. The current sheet can be stable or unstable in dependence on the direction of the gradient of the normal magnetic field component. The obtained dispersion function is used for calculation of the flapping wave disturbances, which are produced by the given initial Gaussian perturbation at the center of the current sheet and propagating towards the flanks. The propagating flapping pulse has a smooth leading front, and a small scale oscillating trailing front, because the short wave oscillations propagate much slower than the long wave ones.


Доп.точки доступа:
Erkaev, N.V.; Еркаев, Николай Васильевич; Semenov, V.S.; Kubyshkin, I.V.; Kubyshkina, M.V.; Biernat, H.K.; RFBR [N07-05-00776-a, N 07-05-00135]; SFU [N 10]; RAS [2.16, 16.3]; Austrian " Fonds zur Forderung der wissenschaftlichen Forschung" [P20341-N16]; Osterreichischer Austauschdienst [I.2/04]

[Text] / V. V. Denisenko, V. V. Bychkov, E. V. Pomozov // Geomagn. Aeron. - 2009. - Vol. 49, Is. 8. - P1275-1277, DOI 10.1134/S0016793209080489. - Cited References: 4. - This work was supported by the Russian Foundation for Basic Research (project no. 07-05-00135) and the Russian Academy of Sciences (program nos. 2.16 and 16.3). . - ISSN 0016-7932РУБ Geochemistry & Geophysics

Аннотация: The spatial distributions of electric fields and currents in the Earth's atmosphere are calculated. Electric potential distributions typical of substorms and quiet geomagnetic conditions are specified in the ionosphere. The Earth is treated as a perfect conductor. The atmosphere is considered as a spherical layer with a given height dependence of electrical conductivity. With the chosen conductivity model and an ionospheric potential of 300 kV with respect to the Earth, the electric field near the ground is vertical and reaches 110 Vm(-1). With the 60-kV potential difference in the polar cap of the ionosphere, the electric field disturbances with a vertical component of up to 13 V m(-1) can occur in the atmosphere. These disturbances are maximal near the ground. If the horizontal scales of field nonuniformity are over 100 km, the vertical component of the electric field near the ground can be calculated with the one-dimensional model. The field and current distributions in the upper atmosphere can be obtained only from the three-dimensional model. The numerical method for solving electrical conductivity problems makes it possible to take into account conductivity inhomogeneities and the ground relief.


Доп.точки доступа:
Denisenko, V.V.; Денисенко, Валерий Васильевич; Bychkov, V.V.; Pomozov, E.V.; Помозов, Егор Владимирович; Russian Foundation for Basic Research [07-05-00135]; Russian Academy of Sciences

[Text] / D. B. Korovinskiy [et al.] // Adv. Space Res. - 2011. - Vol. 48, Is. 9. - P1531-1536, DOI 10.1016/j.asr.2011.07.008. - Cited References: 12. - This work is supported by the Austrian Science Fund under project 1193-N16, by RFBR Grant No. 09-05-91000-ANF-a, by SPSU grant No. 11.38.47.2011, and by the European Union Seventh Framework Programme [FP7/2007-2013] under grant agreement No. 269198 - Geoplasmas (Marie Curie International Research Staff Exchange Scheme). V.S. Semenov thanks also ISSI for hospitality and financial support. . - ISSN 0273-1177РУБ Astronomy & Astrophysics + Geosciences, Multidisciplinary + Meteorology & Atmospheric Sciences

Аннотация: A linear MHD instability of the electric current sheet, characterized by a small normal magnetic field component, varying along the sheet, is investigated. The tangential magnetic field component is modeled by a hyperbolic function, describing Harris-like variations of the field across the sheet. For this problem, which is formulated in a 3D domain, the conventional compressible ideal MHD equations are applied. By assuming Fourier harmonics along the electric current, the linearized 3D equations are reduced to 2D ones. A finite difference numerical scheme is applied to examine the time evolution of small initial perturbations of the plasma parameters. This work is an extended numerical study of the so called "double gradient instability", - a possible candidate for the explanation of flapping oscillations in the magnetotail current sheet, which has been analyzed previously in the framework of a simplified analytical approach for an incompressible plasma. The dispersion curve is obtained for the kink-like mode of the instability. It is shown that this curve demonstrates a quantitative agreement with the previous analytical result. The development of the instability is investigated also for various enhanced values of the normal magnetic field component. It is found that the characteristic values of the growth rate of the instability shows a linear dependence on the square root of the parameter, which scales uniformly the normal component of the magnetic field in the current sheet. (C) 2011 COSPAR. Published by Elsevier Ltd. All rights reserved.


Доп.точки доступа:
Korovinskiy, D.B.; Ivanova, V.V.; Erkaev, N.V.; Еркаев, Николай Васильевич; Semenov, V.S.; Ivanov, I.B.; Biernat, H.K.; Zellinger, M.

[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.

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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)