Труды сотрудников ИВМ СО РАН

[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

/ M. Desroche [et al.] // J. Geophys. Res-Space Phys. - 2012. - Vol. 117. - Ст. A07202, DOI 10.1029/2012JA017621. - Cited References: 50. - The authors thank Chris Arridge for initially suggesting this project. The authors are thankful to Adam Masters, Bob Ergun, Jack Gosling, Martin Goldman, and Dmitri Uzdensky for helpful discussions and guidance. This work was supported by NASA's NESSF program and JUNO mission. . - ISSN 0148-0227РУБ Astronomy & Astrophysics

Аннотация: Using idealized models of the magnetosheath and magnetosphere magnetic fields, plasma densities, and plasma flow, we test for the steady state viability of processes mediating the interaction between the solar wind and the Jovian magnetosphere. The magnetopause is modeled as an asymmetric paraboloid with variable asymmetry. The subsolar standoff of the magnetopause has been shown to exhibit a bimodal probability distribution (Joy et al., 2002). Only the expanded magnetopause is considered, with a standoff of similar to 90 R-J. We test where on the magnetopause surface large-scale reconnection may be affected by either a shear flow or diamagnetic drift due to a pressure gradient across the magnetopause boundary. We also test for the onset of the Kelvin-Helmholtz instability. We find that reconnection is inhibited on the dawn flank due to the large shear flows in this region, regardless of magnetopause shape or interplanetary magnetic field orientation. The presence of a high energy plasma population in the magnetosphere may inhibit reconnection over much of the magnetopause area, except when the fields are antiparallel. Additionally, most of the dawn flank of the magnetopause is Kelvin-Helmholtz unstable, regardless of magnetopause asymmetry; and the dusk flank tailward of the planet is Kelvin-Helmholtz unstable when the magnetopause is highly oblate.


Доп.точки доступа:
Desroche, M.; Bagenal, F.; Delamere, P.A.; Erkaev, N.V.; Еркаев, Николай Васильевич

[Text] / N.I. Kosarev, N.Y. Shaparev // Quantum Electron. - 2009. - Vol. 39, Is. 12. - pp. 1112-1116, DOI 10.1070/QE2009v039n12ABEH014094. - Cited References: 13 . - ISSN 1063-7818РУБ Engineering, Electrical & Electronic + Physics, Applied

Аннотация: We report a computer simulation study of light absorption, scattering and emission at 397 nm in an ultracold calcium ion plasma under resonant excitation. The results point to spectral asymmetry of light scattering, nonlinear absorption, and emission in the plasma. An approach is proposed for ultracold plasma diagnostics using resonant optical characteristics.


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

[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] / N. V. Erkaev, C. J. Farrugia, H. K. Biernat // Planet Space Sci. - 2003. - Vol. 51, Is. 12. - P745-755, DOI 10.1016/S0032-0633(03)00111-9. - Cited References: 36 . - ISSN 0032-0633РУБ Astronomy & Astrophysics

Аннотация: The magnetized solar wind carries a large amount of energy but only a small fraction of it enters the magnetosphere and powers its dynamics. Numerous observations show that the interplanetary magnetic field (IMF) is a key parameter regulating the solar wind-magnetosphere interaction. The main factor determining the amount of energy extracted from the solar wind flow by the magnetosphere is the plasma flow structure in the region adjacent to the sunward side of the magnetopause. While compared to the energy of the solar wind flow the IMF magnetic energy is relatively weak, it is considerably enhanced in a thin layer next to the dayside magnetopause variously called the plasma depletion layer or magnetic barrier. Important features of this barrier/layer are (i) a pile-up of the magnetic field with (ii) a concurrent decrease of density, (iii) enhancement of proton temperature anisotropy, (iv) asymmetry of plasma flow caused by magnetic field tension. and (v) characteristic wave emissions (ion cyclotron waves). Importantly, the magnetic barrier can be considered as an energy source for magnetic reconnection. While the steady-state magnetic barrier has been extensively examined, non-steady processes therein have only been addressed by a few authors. We discuss here two non-steady aspects related to variations of the magnetic barrier caused by (i) a north-to-south rotation of the IMF, and (ii) by pulses of magnetic field reconnection at the magnetopause. When the IMF rotates smoothly from north-to-south, a transition layer is shown to appear in the magnetosheath which evolves into a thin layer bounded by sharp gradients in the magnetic field and plasma quantities. For a given reconnection rate and calculated parameters of the magnetic barrier, we estimate the duration and length scale of a reconnection pulse as a function of the solar wind parameters. Considering a sudden decrease of the magnetic field near the magnetopause caused by the reconnection pulse, we study the relaxation process of the magnetic barrier. We find that the relaxation time is longer than the duration of the reconnection pulse for large Alfved-Mach numbers. (C) 2003 Elsevier Ltd. All rights reserved.


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

[Text] / C. J. Farrugia [et al.] // J. Geophys. Res-Space Phys. - 1998. - Vol. 103, Is. A4. - P6703-6727DOI 10.1029/97JA03248. - Cited References: 39 . - РУБ Astronomy & Astrophysics

Аннотация: We present maximum growth rate charts of the Kelvin-Helmholtz (KH) and Rayleigh-Taylor (RT) instabilities at the dayside magnetopause (MP), considering two orientations of the interplanetary magnetic field (IMF) (due north and 30 degrees west of north). We input parameters in the plasma depletion layer calculated from an MHD code. We study both a sharp MP transition and an MP with an attached boundary layer ("thin" and "thick" approximations, respectively). Our analysis applies to wavelengths (lambda) from similar to 2 x 10(3) km to less than or equal to 9 R-E. Thin model results are as follows: For a stationary MP and due north IMF, the off-noon, low-latitude MP is very low shear (less than or equal to 10 degrees) and is substantially KH active. With an IMF inclined to north, extremely low shear, KH-active regions are confined to two strips, one in each hemisphere, where short lambda perturbations are generated, which propagate as surface ripples on the high-latitude, duskside MP. For a sunward accelerating magnetopause and IMF north, a large part of the MP is unstable. With an inclined IMF, the KH+RT unstable strips are broader and growth rates are higher. Thick model results are as follows: For IMF due north and a stationary MP, the middle-to high-latitude MP is stable. At middle to low latitudes, the inner edge of the boundary layer (IEBL) is active, except fora 2-hour local time band on either side of noon. For the inclined IMF, the MP is stable for long lambda, with activity for short lambda confined to two strips, as before, with slightly reduced growth rates. For the IEBL, a clear dawn-dusk asymmetry in KH activity is evident. When the MP accelerates sunward and the IMF points north, we have to consider also the lambda of the perturbation. For short lambda, growth rates are enhanced with respect to stationarity at both the NIP and the IEBL. While there are extensive regions of negligible growth at the MP, the entire IEBL is RT + KH unstable. We give an example of a long lambda perturbation where both interfaces are coupled and oscillate together. Finally, for an inclined IMF, we have at the MP unstable strips which are wider and have higher growth rates. The IEBL, by contrast, is completely destabilized, with larger growth rates than under stationary conditions.

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Доп.точки доступа:
Farrugia, C.J.; Gratton, F.T.; Bender, L.; Biernat, H.K.; Erkaev, N.V.; Еркаев, Николай Васильевич; Quinn, J.M.; Torbert, R.B.; Denisenko, V.V.; Денисенко, Валерий Васильевич

[Text] / H. K. BIERNAT [et al.] // Planet Space Sci. - 1995. - Vol. 43, Is. 9. - P1105-1120, DOI 10.1016/0032-0633(95)00054-9. - Cited References: 31 . - ISSN 0032-0633РУБ Astronomy & Astrophysics

Аннотация: We use the magnetohydrodynamic approach to calculate all plasma and magnetic field quantities along a line normal to the magnetopause, beginning at the bow shock, through the magnetosheath and magnetopause, and into the magnetosphere. Our method is based on a perturbation calculation, where we expand in orders of 1/M(A infinity), with M(A infinity) the Alfven Mach number upstream of the bow shock. The calculations are carried out (1) in the noon-midnight meridian at latitudes just south of the northern cusp, and (2) in the equatorial flank region. Our calculations are for an interplanetary magnetic field (IMF) which is directed perpendicular to the upstream solar wind. We consider two orientations of the IMF. In one case, the interplanetary field points due south, i.e. antiparallel to the magnetospheric field in the subsolar point. In the second case, it lies in the equatorial plane and points from dusk to dawn. For each of these different orientations of the IMF, in situ observations of reconnection have been made. In the magnetosheath region adjacent to the magnetopause, i.e. in the so-called magnetic barrier, the magnetic forces react back on the plasma flow. This effect is included consistently in the calculation by the use of a special coordinate system. The magnetic field tension accelerates the plasma in a direction perpendicular to the field and thus the magnetic field produces an asymmetry in the flow field. At the magnetopause we describe shock-type reconnection, taking as input on the magnetosheath side the results of the above calculation and taking at the magnetospheric side typical values for the outer boundary of the magnetosphere. The format in which the results are presented is similar to that used in the presentation of bulk parameters and magnetic field measurements obtained from spacecraft.


Доп.точки доступа:
BIERNAT, H.K.; BACHMAIER, G.A.; KIENDL, M.T.; Erkaev, N.V.; Еркаев, Николай Васильевич; MEZENTSEV, A.V.; FARRUGIA, C.J.; SEMENOV, V.S.; RIJNBEEK, R.P.

[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 0953-4075РУБ Optics + Physics, Atomic, Molecular & Chemical

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

/ A. V. Lapko, V. A. Lapko // Meas. Tech. - 2014. - Vol. 57, Is. 7. - P740-744, DOI 10.1007/s11018-014-0529-6 . - ISSN 0543-1972
Аннотация: The choice of an optimal number of sampling intervals in the domain of definition of the probability density is studied as a function of the antikurtosis coefficient. Quantitative relationships between the sampling coefficient and the antikurtosis are found for symmetric and nonsymmetric distributions. Their features are analyzed for different utilization conditions. © 2014, Springer Science+Business Media New York.

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Держатели документа:
Institute of Computational Modelling, Siberian Branch of the Russian Academy of SciencesKrasnoyarsk, Russian Federation
Reshetnev Siberian State Aerospace UniversityKrasnoyarsk, Russian Federation
ИВМ СО РАН

Доп.точки доступа:
Lapko, A.V.; Лапко, Александр Васильевич; Lapko, V.A.; Лапко, Василий Александрович

/ D. Kubyshkina [et al.] // Adv. Space Res. - 2015. - Vol. 56, Is. 8. - P1699-1706, DOI 10.1016/j.asr.2015.07.023 . - ISSN 0273-1177
Аннотация: We study the dependence of the flapping oscillations on the magnetotail current sheet bending, which is caused by the dipole tilt. Observations show that flapping waves propagate from the center of the current sheet to its flanks with a velocity one order of magnitude less than typical Alfven speed. For our analysis we use the double gradient model (Erkaev et al., 2009) of the flapping oscillations, which predicts a small minimum of the total pressure (gas plus magnetic) across the current layer. It is the depth of the potential well in the total pressure which defines the period and the speed of the flapping waves. Using the extension of the Kan/Manankova equilibriums for the non-zero dipole tilt we investigate the depth of the potential well with respect to the current sheet bending rate. We show that with the growth of the dipole tilt angle the depth of the potential well becomes smaller, the period of the flapping oscillations increases, and oscillations become nonlinear. There exists the critical tilt angle, where the potential well disappears and flapping regime changes from oscillations to instability. © 2015 COSPAR. Published by Elsevier Ltd. All rights reserved.

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Держатели документа:
Saint Petersburg State University, Saint-Petersburg, Russian Federation
Institute of Computational Modelling SB RAS, Krasnoyarsk, Russian Federation
Siberian Federal University, Krasnoyarsk, Russian Federation; Siberian Federal University, Krasnoyarsk, Russian Federation

Доп.точки доступа:
Kubyshkina, D.; Semenov, V.; Erkaev, N.V.; Еркаев, Николай Васильевич; Kubyshkin, I.

/ M. Kubyshkina [et al.] // Geophys. Res. Lett. - 2018. - Vol. 45, Is. 9. - P3760-3767, DOI 10.1002/2017GL076268 . - ISSN 0094-8276
Аннотация: We analyze two substorm onset lists, produced by different methods, and show that the (Bx·vz) product of the solar wind (SW) velocity and interplanetary magnetic field (IMF) components for two thirds of all substorm onsets has the same sign as IMF Bz. The explanation we suggest is the efficient displacement of the magnetospheric plasma sheet due to IMF Bx and SW flow vz, which both force the plasma sheet moving in one direction if the sign of (Bx·vz) correlates with the sign Bz. The displacement of the current sheet, in its turn, increases the asymmetry of the magnetotail and can alter the threshold of substorm instabilities. We study the SW and IMF data for the 15-year period (which comprises two substorm lists periods and the whole solar cycle) and reveal the similar asymmetry in the SW, so that the sign of (Bx·vz) coincides with the sign of IMF Bz during about two thirds of all the time. This disproportion can be explained if we admit that about 66% of IMF Bz component is transported to the Earth's orbit by the Alfven waves with antisunward velocities. ©2018. American Geophysical Union. All Rights Reserved.

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Держатели документа:
Earth Physics Department, Saint Petersburg State University, Saint Petersburg, Russian Federation
Institute of Computational Modelling, Federal Research Center “Krasnoyarsk Science Center SB RAS”, Akademgorodok, Russian Federation
Department of Applied Mechanics, Siberian Federal University, Krasnoyarsk, Russian Federation
Finnish Meteorological Institute, Helsinki, Finland
Department of Climate and Space Sciences and Engineering, University of Michigan, Ann Arbor, MI, United States

Доп.точки доступа:
Kubyshkina, M.; Semenov, V.; Erkaev, N.; Gordeev, E.; Dubyagin, S.; Ganushkina, N.; Shukhtina, M.