Труды сотрудников ИВМ СО РАН

/ C. J. Farrugia [et al.] // J. Atmos. Sol.-Terr. Phys. - 2013. - Vol. 99. - P14-26, DOI 10.1016/j.jastp.2012.11.014. - Cited References: 53. - C.J.F. is supported by NASA Grant NNX10AQ29G and NSF Grant AGS-1140211. N.V.E. acknowledges support from Austrian Science Fund Project I193-N16 and RFBR Grant no 12-05-00152-a. N.L. acknowledges support from NSF Grant AGS-1140211. Work at LANL was conducted under the auspices of the U.S. Department of Energy with partial support from NASA and NSF. . - 13. - ISSN 1364-6826РУБ Geochemistry & Geophysics + Meteorology & Atmospheric Sciences

Аннотация: The interaction of interplanetary coronal mass ejections (ICMEs) and magnetic clouds (MCs) with the Earth's magnetosphere exhibits various interesting features principally due to interplanetary parameters which change slowly and reach extreme values of long duration. These, in turn, allow us to explore the geomagnetic response to continued and extreme driving of the magnetosphere. In this paper we shall discuss elements of the following: (i) anomalous features of the flow in the terrestrial magnetosheath during ICME/MC passage and (ii) large geomagnetic disturbances when total or partial mergers of ICMEs/MCs pass Earth. In (i) we emphasize two roles played by the upstream Alfven Mach number in solar wind-magnetosphere interactions: (i) It gives rise to wide plasma depletion layers. (ii) It enhances the magnetosheath flow speed on draped magnetic field lines. (By plasma depletion layer we mean a magnetosheath region adjacent to the magnetopause where magnetic forces dominate over hydrodynamic forces.) In (ii) we stress that the ICME mergers elicit geoeffects over and above those of the individual members. In addition, features of the non-linear behavior of the magnetosphere manifest themselves. (C) 2012 Elsevier Ltd. All rights reserved.


Доп.точки доступа:
Farrugia, C.J.; Erkaev, N.V.; Еркаев, Николай Васильевич; Jordanova, V.K.; Lugaz, N.; Sandholt, P.E.; Muhlbachler, S.; Torbert, R.B.

/ V.K. Andreev, V.B. Bekezhanova // J. Appl. Mech. Tech. Phys. - 2013. - Vol. 54, Is. 2. - P171-184, DOI 10.1134/S0021894413020016. - Cited References: 157. - This work was supported by Russian Foundation for Basic Research (Grant No. 11-01-00283) and the Integration Project of SB RAS No. 38. . - 14. - ISSN 0021-8944РУБ Mechanics + Physics, Applied

Аннотация: This paper gives a review of studies of flow stability for viscous heat-conducting fluids.


Доп.точки доступа:
Andreev, V.K.; Андреев, Виктор Константинович; Bekezhanova, V.B.; Бекежанова, Виктория Бахытовна

/ 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 0038-0938РУБ 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.

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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.

[Text] / H. K. Biernat [et al.] // Planet Space Sci. - 2007. - Vol. 55, Is. 12. - P1793-1803, DOI 10.1016/j.pss.2007.01.006. - Cited References: 28 . - ISSN 0032-0633РУБ Astronomy & Astrophysics

Аннотация: In this paper, the solar wind flow around Venus is modeled as a nondissipative fluid which obeys the ideal magnetohydrodynamic equations extended for mass loading processes. The mass loading parameter is calculated for four different cases, corresponding to solar minimum and maximum XUV flux and to nominal and low solar wind velocity. We get smooth profiles of the field and plasma parameters in the magnetosheath. Based on the results of this flow model, we investigate the occurrence of the Kelvin-Helmholtz (K-H) instability at the equatorial flanks of the ionopause of Venus. By comparing the instability growth time with the propagation time of the K-H wave, we find that the K-H instability can evolve at the ionopause for all four solar wind conditions. (C) 2007 Elsevier Ltd. All rights reserved.


Доп.точки доступа:
Biernat, H.K.; Erkaev, N.V.; Еркаев, Николай Васильевич; Amerstorfer, U.V.; Penz, T.; Lichtenegger, H.I.M.

[Text] / N. V. Erkaev [et al.] // Ann. Geophys. - 2007. - Vol. 25, Is. 1. - P145-159. - Cited References: 32 . - ISSN 0992-7689РУБ Astronomy & Astrophysics + Geosciences, Multidisciplinary + Meteorology & Atmospheric Sciences

Аннотация: Mars has no global intrinsic magnetic field, and consequently the solar wind plasma interacts directly with the planetary ionosphere. The main factors of this interaction are: thermalization of plasma after the bow shock, ion pick-up process, and the magnetic barrier effect, which results in the magnetic field enhancement in the vicinity of the obstacle. Results of ideal magnetohydrodynamic and hybrid simulations are compared in the subsolar magnetosheath region. Good agreement between the models is obtained for the magnetic field and plasma parameters just after the shock front, and also for the magnetic field profiles in the magnetosheath. Both models predict similar positions of the proton stoppage boundary, which is known as the ion composition boundary. This comparison allows one to estimate applicability of magnetohydrodynamics for Mars, and also to check the consistency of the hybrid model with Rankine-Hugoniot conditions at the bow shock. An additional effect existing only in the hybrid model is a diffusive penetration of the magnetic field inside the ionosphere. Collisions between ions and neutrals are analyzed as a possible physical reason for the magnetic diffusion seen in the hybrid simulations.


Доп.точки доступа:
Erkaev, N.V.; Еркаев, Николай Васильевич; Bosswetter, A.; Motschmann, U.; Biernat, H.K.

[Text] / T. Penz [et al.] ; ed.: O. Witasse // PLANETARY ATMOSPHERES, IONOSPHERES, AND MAGNETOSPHERES. Ser. ADVANCES IN SPACE RESEARCH : ELSEVIER SCIENCE LTD, 2005. - Vol. 36: 35th COSPAR Scientific Assembly (JUL 18-25, 2004, Paris, FRANCE), Is. 11. - P2049-2056, DOI 10.1016/j.asr.2004.11.039. - Cited References: 20 . - ISBN 0273-1177РУБ Engineering, Aerospace + Astronomy & Astrophysics + Geosciences, Multidisciplinary + Meteorology & Atmospheric Sciences

Аннотация: It is known from Pioneer Venus measurements that at the Venusian ionopause wave-like structures develop, which can detach in the form of ionospheric plasma clouds. This phenomenon is assumed to occur due to the Kelvin-Helmholtz instability, which can appear in large regions of the Venusian ionopause. Recent studies of Mars Global Surveyor measurements indicate that wave-like structures and plasma clouds also detach from the Martian ionopause. Therefore, these features seem to be common for the solar wind interaction of non-magnetized planets. We study the conditions at the Martian ionopause with respect to the occurrence of several MHD instabilities. The conditions in the magnetosheath are modeled by a semi-analytical MHD simulation that includes mass loading. The ionospheric parameter needed for the model calculations are taken from a global hybrid model. The stability of the Martian ionopause against the Kelvin-Helmholtz, the Rayleigh-Taylor, and the interchange instability is analyzed. Further, we suggest that including the Hall term in the description of the Kelvin-Helmholtz instability gives a current in the planetary boundary layer resulting in a shear flow compared with the ionospheric plasma, which can lead to an unstable boundary layer near the subsolar point. Since the interchange instability depends on the curvature of the magnetic field lines, we additionally study the influence of the strong curvature of the Martian ionopause due to the localized, remnant, crustal magnetism appearing mainly in the southern hemisphere of Mars. (c) 2004 COSPAR. Published by Elsevier Ltd. All rights reserved.


Доп.точки доступа:
Penz, T.; Arshukova, I.L.; Terada, N.; Shinagawa, H.; Erkaev, N.V.; Еркаев, Николай Васильевич; Biernat, H.K.; Lammer, H.; Witasse, O. \ed.\

[Text] / M. Blanc, R. Kallenbach, N. V. Erkaev // Space Sci. Rev. - 2005. - Vol. 116: Workshop on Comparative Study of the Outer Planets before the Exploration of Saturn (JAN 12-14, 2004, Bern, SWITZERLAND), Is. 01.02.2013. - P227-298, DOI 10.1007/s11214-005-1958-y. - Cited References: 202 . - ISSN 0038-6308РУБ Astronomy & Astrophysics

Аннотация: This article proposes a short review of our present knowledge of solar system magnetospheres, with the purpose of placing the study of Saturn's inagnetosphere in the context of a comparative approach. We describe the diversity of solar system magnetospheres and the underlying causes of this diversity: nature and magnetization state of the planetary obstacle, presence or not of a dense atmosphere, rotation state of the planet, existence of a system of satellites, rings and neutral gas populations in orbit around the planet. We follow the "russian doll" hierarchy of solar system magnetospheres to briefly describe the different objects of this family: the heliosphere, which is the Sun's magnetosphere; the "elementary" magnetospheres of the inner planets, Earth and Mercury; the "complex" magnetospheres of the giant planets, dominated by planetary rotation and the presence of interacting objects within their magnetospheric cavities, some of which, like Ganymede, to or Titan, produce small intrinsic or induced magnetospheres inside the large one. We finally describe the main original features of Saturn's magnetosphere as we see them after the Voyager fly-bys and before the arrival of Cassini at Saturn, and list some of the key questions which Cassini will have to address during its four-year orbital tour.


Доп.точки доступа:
Blanc, M.; Kallenbach, R.; Erkaev, N.V.; Еркаев, Николай Васильевич

[Text] / T. Penz [et al.] // Planet Space Sci. - 2004. - Vol. 52, Is. 13. - P1157-1167, DOI 10.1016/j.pss.2004.06.001. - Cited References: 53 . - ISSN 0032-0633РУБ Astronomy & Astrophysics

Аннотация: Mars Global Surveyor detected cold electrons above the Martian ionopause, which can be interpreted as detached ionospheric plasma clouds. Similar observations by the Pioneer Venus Orbiter electron temperature probe showed also extreme spatial irregularities of electrons in the form of plasma clouds on Venus, which were explained by the occurrence of the Kelvin-Helmholtz instability. Therefore, we suggest that the Kelvin-Helmholtz instability may also detach ionospheric plasma clouds on Mars. We investigate the instability growth rate at the Martian ionopause resulting from the flow of the solar wind for the case where the interplanetary magnetic field is oriented normal to the flow direction. Since the velocity shear near the subsolar point is very small, this area is stable with respect to the Kelvin-Helmholtz instability. We found that the highest flow velocities are reached at the equatorial flanks near the terminator plane, while the maximum plasma density in the terminator plane appears at the polar areas. By comparing the instability growth rate with the magnetic barrier formation time, we found that the instability can evolve into a non-linear stage at the whole terminator plane but preferably at the equatorial flanks. Escape rates of O+ ions due to detached plasma clouds in the order of about 2 x 10(23)-3 x 10(24) s(-1) are found. Thus, atmospheric loss caused by the Kelvin-Helmholtz instability should be comparable with other non-thermal loss processes. Further, we discuss our results in view of the expected observations of heavy ion loss rates by ASPERA-3 on board of Mars Express. (C) 2004 Elsevier Ltd. All rights reserved.


Доп.точки доступа:
Penz, T.; Erkaev, N.V.; Еркаев, Николай Васильевич; Biernat, H.K.; Lammer, H.; Amerstorfer, U.V.; Gunell, H.; Kallio, E.; Barabash, S.; Orsini, S.; Milillo, A.; Baumjohann, W.

[Text] / C. J. Farrugia [et al.] // SPACE WEATHER 2000. Ser. ADVANCES IN SPACE RESEARCH-SERIES : PERGAMON-ELSEVIER SCIENCE LTD, 2003. - Vol. 31: PSW1/C0 1/D0 5/E2 5/F2 0 Symposium of the COSPAR Scientific Panel on Space Weather held at the 33rd COSPAR Scientific Assembly (JUL, 2000, WARSAW, POLAND), Is. 4. - P1105-1110, DOI 10.1016/S0273-1177(02)00889-X. - Cited References: 16 . - ISBN 0273-1177РУБ Engineering, Aerospace + Astronomy & Astrophysics + Geosciences, Multidisciplinary + Meteorology & Atmospheric Sciences

Аннотация: With its similar to12 h-long period of strongly northward magnetic field, the coronal mass ejection which passed Earth on April 11, 1997 affords an excellent opportunity of studying Kelvin-Helmholtz (KH) activity at the dayside magnetopause as a function of the clock angle, theta, of the interplanetary field (IMF). A correlation between the wavelength of the KH waves and theta may be expected on the basis of our recent model, where activity is generated in strips which broaden as theta decreases. We identify two 2-hour long intervals of small, but different, clock angles, and make a preliminary test of model predictions, using records from two ground magnetometer chains, both on the dayside. Taking into account the local time of the magnetometer arrays and the geometry of the KH-active strips, we show that the resonant stations measured considerably more spectral power density in the 3-4 mHz range during the phase with smaller theta. Moreover, as theta increases, the spectral power spectrum shifted to higher frequencies that were almost absent for smaller theta. (C) 2003 COSPAR. Published by Elsevier Science Ltd. All rights reserved.


Доп.точки доступа:
Farrugia, C.J.; Gratton, F.T.; Torbert, R.B.; Bender, L.; Gnavi, G.; Ogilvie, K.W.; Erkaev, N.V.; Еркаев, Николай Васильевич; Lepping, R.P.; Stauning, P.

[Text] / H. K. Biernat [et al.] // Nonlinear Process Geophys. - 2000. - Vol. 7: 24th General Assembly of the European-Geophysical-Society (APR 19-23, 1999, THE HAGUE, NETHERLANDS), Is. 03.04.2013. - P201-209. - Cited References: 34 . - ISSN 1023-5809РУБ Geochemistry & Geophysics + Meteorology & Atmospheric Sciences

Аннотация: The study of the interaction of the solar wind with magnetized and unmagnetized planets forms a central topic of space research. Focussing on planetary magnetosheaths, we review some major developments in this field. Magnetosheath structures depend crucially on the orientation of the interplanetary magnetic field, the solar wind Alfven Mach number, the shape of the obstacle (axisymmetric/non-axisymmetric, etc.), the boundary conditions at the magnetopause (low/high magnetic shear), and the degree of thermal anisotropy of the plasma. We illustrate the cases of Earth, Jupiter and Venus. The terrestrial magnetosphere is axisymmetric and has been probed in situ by many spacecraft. Jupiter's magnetosphere is highly non-axisymmetric. Furthermore, we study magnetohydrodynamic effects in the Venus magnetosheath.


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

[Text] / H. K. Biernat, N. V. Erkaev, C. J. Farrugia // J. Geophys. Res-Space Phys. - 1999. - Vol. 104, Is. A6. - P12617-12626, DOI 10.1029/1999JA900032. - Cited References: 37 . - ISSN 0148-0227РУБ Astronomy & Astrophysics

Аннотация: We describe the "magnetic string" approach to integrating the dissipationless magnetohydrodynamic (MHD) equations for flow around planetary obstacles and apply it to some aspects of the flow in the magnetosheath of Venus. Our method has both analytical and numerical components and is particularly suited to study the structure of the magnetic barrier (depletion layer). We do not include ion pickup processes and thus discuss only the contribution to the structure of the Venus magnetosheath made by the flow of the shocked solar wind. We work with an interplanetary magnetic field which is directed orthogonal to the solar wind bulk velocity. Magnetic forces on the flow are strongly dependent on the Alfven Mach number upstream of the bow shock, and one aim of this work is to study the dependence of field and flow quantities in the Venus magnetosheath on this parameter, thus allowing further future comparisons with data under a variety of interplanetary conditions. A second aim is to compare our MHD model results to a? synopsis of observations made by the Pioneer Venus Orbiter. As one main conclusion, we show that this method leads, in principle, to a standoff bow shock position in good agreement with observations. We find, namely, that for a low but reasonable Alfven Mach number, our MHD-modeled magnetosheath is only similar to 3.6% thinner in the Sun-Venus direction than that given by observations. Our method is complementary to three-dimensional, global MHD simulations of the solar wind-Venus interaction and offers versatility to modeling other aspects of the complicated interaction of the solar wind with Venus.


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

[Text] / C. J. Farrugia [et al.] // J. Geophys. Res-Space Phys. - 1997. - Vol. 102, Is. A6. - P11315-11324DOI 10.1029/97JA00410. - Cited References: 29 . - РУБ Astronomy & Astrophysics

Аннотация: Together with the magnetic shear across the magnetopause, the solar wind Alfven Mach number, M-A infinity plays a central role in determining the structure of the magnetosheath. Recent theoretical modeling has shown, in particular, that as M-A infinity decreases, the region adjacent to the sunward side of the magnetopause where the interplanetary magnetic field (IMF) exerts a strong influence on the flow (i.e., the so-called ''plasma depletion layer''), is no longer confined to a thin layer similar to 0.3 Earth radii (R-E) thick but occupies an increasingly larger fraction of the magnetosheath. Furthermore, the model predicts the possibility of a plasma depletion layer for low M-A infinity, irrespective of the size of the magnetic shear at the magnetopause, In this paper we study three examples of low latitude ISEE 2 passes through the dayside magnetosheath near noon: December 3, 1979; October 5, 1979; and November 11, 1979, In all three examples, MA, was lower than normal. During the December 3 pass (which we treat qualitatively), we find evidence of a plasma depletion layer when the IMF was pointing south, On the other two passes (which we study quantitatively), the interplanetary magnetic field was strongly northward pointing, leading to low magnetic shear at the respective magnetopause crossings, The October 5 pass was under steady interplanetary conditions and we find good agreement between theory and data, Temporal variations of the interplanetary medium during the November 11 pass necessitated an extension of the steady state theory to encompass piecewise steady (on average) interplanetary conditions, Better agreement with the data results when the theory is extended further to correct the total pressure at the sunward side of the magnetopause by integrating the magnetic tension term across the layer. For wide plasma depletion layers, this correction can be substantial.


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

[Text] / N. V. Erkaev [et al.] // Geophys. Res. Lett. - 2011. - Vol. 38. - Ст. L01104, DOI 10.1029/2010GL045998. - Cited References: 20. - This work was done while N.V.E. was on a research visit to the Space Science Center of UNH. This work is supported by RFBR grant N 09-05-91000-ANF_a and also by the Austrian "Fonds zur Forderung der wissenschaftlichen Forschung" under project I 193-N16 and the "Verwaltungsstelle fur Auslandsbeziehungen" of the Austrian Academy of Sciences. Work by C.J.F. was supported by NASA grants NNX10AQ29G and NNX08AD11G. . - ISSN 0094-8276РУБ Geosciences, Multidisciplinary

Аннотация: We study the acceleration of magnetosheath plasma using a semi-analytical magnetic string approach for a range of solar wind Alfven Mach numbers, M-A, between 2 and 20. We work with an IMF vector perpendicular to the solar wind velocity, V-sw, and pointing north. We do not invoke magnetic reconnection. Our results indicate that magnetosheath speeds can exceed the solar wind speed, and the ratio V/V-sw increases with decreasing M-A. Analyzing the dependence of this ratio on M-A, we find that for M-A = 2, maximum V/V-sw approximate to 1.6, and for M-A = 10-20, maximum V/V-sw varies from 1.21 to 1.13. Maximum speeds occur a few Earth radii (R-E) tailward of the dawn-dusk terminator. The thickness of the accelerated flow layer varies as M-A(-2). Taking the magnetopause subsolar distance as 10 R-E, we find typical values for the thickness of similar to 4 R-E for M-A = 3 and 0.35 R-E for M-A = 10. The physical mechanism is that of draping of the magnetic field lines around the magnetosphere, and the associated magnetic tension and total pressure gradient forces acting on the flow. For lower M-A the plasma depletion is stronger, and thus the acceleration produced by the pressure gradient is larger. An additional acceleration is produced by the magnetic tension, which is stronger for smaller M-A. At the dayside the pressure gradient and magnetic tension forces both act in the same direction. But tailward of the terminator the magnetic tension starts to act in the opposite direction to the pressure gradient. When the resulting force vanishes, the highest speed is attained. Citation: Erkaev, N. V., C. J. Farrugia, B. Harris, and H. K. Biernat (2011), On accelerated magnetosheath flows under northward IMF, Geophys. Res. Lett., 38, L01104, doi: 10.1029/2010GL045998.


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

[Text] / D. I. Kubyshkina [et al.] // J. Geophys. Res-Space Phys. - 2014. - Vol. 119, Is. 4. - P. 3002-3015, DOI 10.1002/2013JA019477. - Cited References: 32. - We thank C. W. Carlson and J. P. McFadden for use of THEMIS ESA data; K. H. Glassmeier, U. Auster, and W. Baumjohann for the use of FGM data provided under the lead of the Technical University of Braunschweig and with financial support through the German Ministry for Economy and Technology and the German Center for Aviation and Space (DLR) under contract 50 OC 0302. The work was partly supported by SPbU grant 11.38.84.12, by RFBR grants 12-05-00152-a and 12-05-00918-a, and by the grant for support of leading Scientific schools 2836.2014.5. The work of S. Dubyagin and N. Ganushkina was partly supported by the Academy of Finland. This work was supported by the Austrian Science Fund (FWF): I193-N16. N. V. E acknowledges the support by the International Space Science Institute (ISSI, Switzerland) and discussions within the ISSI Team 214 on Flow-Driven Instabilities of the Sun-Earth System. 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). . - ISSN 2169-9380. - ISSN 2169-9402РУБ Astronomy & Astrophysics

Аннотация: Flapping waves are most noticeable large-scale perturbations of the magnetotail current sheet, whose nature is still under discussion. They represent rather slow (an order of magnitude less than typical Alfven speed) waves propagating from the center of the sheet to its flanks with a typical speed of 20-60 km/s, amplitude of 1-2 R-e and quasiperiod of 2-10 min. The double-gradient MHD model, which was elaborated in Erkaev et al. (2007) predicts two (kink and sausage) modes of the flapping waves with differences in their geometry and propagation velocity, but the mode structure is hard to resolve observationally. We investigate the possibility of mode identification by observing the rotation of magnetic field and plasma velocity vectors from a single spacecraft. We test theoretical results by analyzing the flapping oscillations observed by Time History of Events and Macroscale Interactions during Substorms spacecraft and confirm that character of observed rotation is consistent with kink mode determination made by using multispacecraft methods. Also, we checked how the existence of some obstructive conditions, such as noise, combined modes, and multiple sources of the flapping oscillations, can affect on the possibility of the modes separation with suggested method.

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Держатели документа:
ИВМ СО РАН

Доп.точки доступа:
Kubyshkina, D.I.; Sormakov, D.A.; Sergeev, V.A.; Semenov, V.S.; Erkaev, N.V.; Еркаев, Николай Васильевич; Kubyshkin, I.V.; Ganushkina, N.Y.; Dubyagin, S.V.; German Ministry for Economy and Technology; German Center for Aviation and Space (DLR) [50 OC 0302]; SPbU [11.38.84.12]; RFBR [12-05-00152-a, 12-05-00918-a]; grant for support of leading Scientific schools [2836.2014.5]; Academy of Finland; Austrian Science Fund (FWF) [I193-N16]; International Space Science Institute (ISSI, Switzerland); European Union [269198, 218816]

/ D. B. Korovinskiy [et al.] // Ann. Geophys. - 2018. - Vol. 36, Is. 2. - P641-653, DOI 10.5194/angeo-36-641-2018. - Cited References:45. - This study has been supported by the Austrian Science Fund (FWF), P 27012-N27 and I 3506-N27, and by Russian Science Foundation (RSF) grant no. 18-47-05001. The authors thank Anna V. Egorova for her help with preparation of the images, and reviewers for their help in improving the paper. . - ISSN 0992-7689. - ISSN 1432-0576РУБ Astronomy & Astrophysics + Geosciences, Multidisciplinary + Meteorology &

Аннотация: A specific class of solutions of the Vlasov-Maxwell equations, developed by means of generalization of the well-known Harris-Fadeev-Kan-Manankova family of exact two-dimensional equilibria, is studied. The examined model reproduces the current sheet bending and shifting in the vertical plane, arising from the Earth dipole tilting and the solar wind nonradial propagation. The generalized model allows magnetic configurations with equatorial magnetic fields decreasing in a tailward direction as slow as 1/x, contrary to the original Kan model (1/x(3)); magnetic configurations with a single X point are also available. The analytical solution is compared with the empirical T96 model in terms of the magnetic flux tube volume. It is found that parameters of the analytical model may be adjusted to fit a wide range of averaged magnetotail configurations. The best agreement between analytical and empirical models is obtained for the midtail at distances beyond 10-15 R-E at high levels of magnetospheric activity. The essential model parameters (current sheet scale, current density) are compared to Cluster data of magnetotail crossings. The best match of parameters is found for single-peaked current sheets with medium values of number density, proton temperature and drift velocity.

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Держатели документа:
Austrian Acad Sci, Space Res Inst, Graz, Austria.
St Petersburg State Univ, Earths Phys Dept, St Petersburg, Russia.
SBRAS, FRC Krasnoyarsk Sci Ctr, Inst Computat Modelling, Krasnoyarsk, Russia.
Siberian Fed Univ, Appl Mech Dept, Krasnoyarsk, Russia.

Доп.точки доступа:
Korovinskiy, Daniil B.; Kubyshkina, Darya I.; Semenov, Vladimir S.; Kubyshkina, Marina V.; Erkaev, Nikolai V.; Kiehas, Stefan A.; Korovinskiy, Daniil; Austrian Science Fund (FWF) [P 27012-N27, I 3506-N27]; Russian Science Foundation (RSF) [18-47-05001]