Труды сотрудников ИВМ СО РАН

[Text] : статья / V.V. Denisenko [et al.] // J. Atmos. Sol.-Terr. Phys. - 2013. - Vol. 102. - P341-353, DOI 10.1016/j.jastp.2013.05.019. - Cited References: 29. - This work is supported by Grants 09-06-91000, 12-05-00152 from the Russian Foundation for Basic Research. Additional support is due to the Austrian "Fonds zur Forderung der wissenschaftlichen Forschung" under Project I193-N16 and the "Verwaltungsstelle fur Auslandsbeziehungen" of the Austrian Academy of Sciences. The authors are grateful to the unknown reviewers for the fruitful detailed discussion. . - 13. - ISSN 1364-6826РУБ Geochemistry & Geophysics + Meteorology & Atmospheric Sciences

Аннотация: A quasi stationary three dimensional model of electric fields and currents in the conductor that includes the Earth's atmosphere and ionosphere is created. The results of the three dimensional model are simpler regarding interpretation and explanation than two dimensional ones. Known approaches regarding the ionosphere as a boundary condition at the upper boundary of the atmospheric conductor are analyzed. For the investigation of the electric field penetration from ground into the ionosphere it is sufficient to take into account only integral conductivity of the ionosphere. A mathematical simulation has shown that the resulting electric field in the ionosphere is negligible in contrast to the general point of view that such a penetration is a physical process which potentially creates ionospheric precursors of earthquakes. (C) 2013 Elsevier Ltd. All rights reserved.

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

Доп.точки доступа:
Denisenko, V.V.; Денисенко, Валерий Васильевич; Ampferer, M.; Pomozov, E.V.; Помозов, Егор Владимирович; Kitaev, A.V.; Китаев, Анатолий Валерьевич; Hausleitner, W.; Stangl, G.; Biernat, H.K.; Russian Foundation for Basic Research [09-06-91000, 12-05-00152]; Austrian "Fonds zur Forderung der wissenschaftlichen Forschung" [I193-N16]; "Verwaltungsstelle fur Auslandsbeziehungen" of the Austrian Academy of Sciences

[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

[Text] / U.V. Amerstorfer [et al.] // Phys. Plasmas. - 2010. - Vol. 17, Is. 7. - Ст. 72901, DOI 10.1063/1.3453705. - Cited References: 26. - This work was supported by the FWF under Project No. P21051-N16 and also by the RFBR under Grant No. 09-05-91000-ANF_a. . - ISSN 1070-664XРУБ Physics, Fluids & Plasmas

Аннотация: Results of two-dimensional nonlinear numerical simulations of the magnetohydrodynamic Kelvin-Helmholtz instability are presented. A boundary layer of a certain width is assumed, which separates the plasma in the upper layer from the plasma in the lower layer. A special focus is given on the influence of a density increase toward the lower layer. The evolution of the Kelvin-Helmholtz instability can be divided into three different phases, namely, a linear growth phase at the beginning, followed by a nonlinear phase with regular structures of the vortices, and finally, a turbulent phase with nonregular structures. The spatial scales of the vortices are about five times the initial width of the boundary layer. The considered configuration is similar to the situation around unmagnetized planets, where the solar wind (upper plasma layer) streams past the ionosphere (lower plasma layer), and thus the plasma density increases toward the planet. The evolving vortices might detach around the terminator of the planet and eventually so-called plasma clouds might be formed, through which ionospheric material can be lost. For the special case of a Venus-like planet, loss rates are estimated, which are of the order of estimated loss rates from observations at Venus. (C) 2010 American Institute of Physics. [doi:10.1063/1.3453705]


Доп.точки доступа:
Amerstorfer, U.V.; Erkaev, N.V.; Еркаев, Николай Васильевич; Taubenschuss, U.; Biernat, H.K.

[Text] / M. Ampferer [et al.] // Ann. Geophys. - 2010. - Vol. 28, Is. 3. - pp. 779-787. - Cited References: 30. - This work is supported by grants 07 05 00135, 09-06-91000 from the Russian Foundation for Basic Research and by the Program 16.3 of the Russian Academy of Sciences. Additional support is due to the Austrian "Fonds zur Forderung der wissenschaftlichen Forschung" under Project I193-N16 and the "Verwaltungsstelle fur Auslandsbeziehungen" of the Austrian Academy of Sciences. The authors are grateful to the referees whose comments helped considerably to improve the paper. . - ISSN 0992-7689РУБ Astronomy & Astrophysics + Geosciences, Multidisciplinary + Meteorology & Atmospheric Sciences

Аннотация: It is well known that lithospheric electromagnetic emissions are generated before earthquakes occurrence. In our study, we consider the physical penetration mechanism of the electric field from the Earth's surface, through the atmosphere-ionosphere layers, and until its detection in space by satellites. A simplified approach is investigated using the electric conductivity equation, i.e., del((sigma) over cap.del Phi) = 0 in the case of a vertical inclination of the geomagnetic field lines. Particular interest is given to the conductivity profile near the ground and the electric field distribution at the Earth's surface. Our results are discussed and compared to the models of Pulinets et al. (2003) and Denisenko et al. (2008). It is shown that the near ground atmospheric layer with low conductivity decreases the electric field penetration into the ionosphere. The model calculations have demonstrated that the electric field of lithospheric origin is too weak to be observed at satellite altitudes.


Доп.точки доступа:
Ampferer, M.; Denisenko, V.V.; Денисенко, Валерий Васильевич; Hausleitner, W.; Krauss, S.; Stangl, G.; Boudjada, M.Y.; Biernat, H.K.

[Text] / U. V. Amerstorfer [et al.] // Planet Space Sci. - 2007. - Vol. 55, Is. 12. - P1811-1816, DOI 10.1016/j.pss.2007.01.015. - Cited References: 20 . - ISSN 0032-0633РУБ Astronomy & Astrophysics

Аннотация: In this paper, the Kelvin-Helmholtz instability is studied by solving the ideal MHD equations for a compressible plasma. A transition layer of finite thickness between two plasmas, across which the magnitude of the velocity and the density change, is assumed. Growth rates are presented for the transverse case, i.e., the flow velocity is perpendicular to the magnetic field. If only the velocity changes across the boundary layer and the density is kept constant, an important quantity affecting the growth of the Kelvin-Helmholtz instability is the magnetosonic Mach number, which characterizes compressibility. The growth rates for the case when both, the velocity and the density, change are very sensitive to the ratio of the upper plasma density to the lower plasma density: a decrease of the density ratio yields a decrease of the growth rate. Including a density profile is very important for the application of the Kelvin-Helmholtz instability to the solar wind flow around unmagnetized planets, e.g., Venus, where the plasma density increases from the magnetosheath to the ionosphere. (C) 2007 Elsevier Ltd. All rights reserved.


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

[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] / 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] / I. L. Arshukova [et al.] ; ed. E. Kallio // PLANETARY ATMOSPHERES, IONOSPHERES AND PLASMA INTERACTIONS. Ser. ADVANCES IN SPACE RESEARCH : PERGAMON-ELSEVIER SCIENCE LTD, 2004. - Vol. 33: 2nd World Space Congress/34th COSPAR Scientific Assembly (OCT 10-19, 2002, HOUSTON, TEXAS), Is. 2. - P182-186, DOI 10.1016/j.asr.2003.04.015. - Cited References: 12 . - ISBN 0273-1177РУБ Engineering, Aerospace + Astronomy & Astrophysics + Geosciences, Multidisciplinary + Meteorology & Atmospheric Sciences

Аннотация: Within the magnetohydrodynamic (MHD) approach, the interchange instability is studied for the subsolar magnetosheath of Venus. The instability analysis considers the profiles of magnetic field and plasma parameters between the bow shock and the ionopause which are obtained from the numerical MHD solution of the solar wind flow around the ionosphere. With the Fourier transformations, the linearized MILD equations are reduced to a second-order differential equation for the total pressure perturbation as a function of the normal distance from the ionopause. This equation is integrated numerically, and the interchange instability growth rate is obtained as a function of the wave number. The instability growth time is found to be smaller than the time scale of magnetic barrier formation. (C) 2003 COSPAR. Published by Elsevier Ltd. All rights reserved.


Доп.точки доступа:
Arshukova, I.L.; Erkaev, N.V.; Еркаев, Николай Васильевич; Biernat, H.K.; Vogl, D.F.; Kallio, E. \ed.\

[Text] / N. V. Erkaev [et al.] ; ed. N. Thomas [et al.] // IO, EUROPA, TITAN AND CRATERING OF ICY SURFACES. Ser. ADVANCES IN SPACE RESEARCH : ELSEVIER SCIENCE BV, 2001. - Vol. 28: B0 5-D3 6/B0 6-C3 4-D3 7-F3 0/B0 7 Symposium of COSPAR Scientific Commission B held at the 33rd COSPAR Scientific Assembly (JUL, 2000, WARSAW, POLAND), Is. 10. - P1481-1488, DOI 10.1016/S0273-1177(01)00550-6. - Cited References: 16 . - ISBN 0273-1177РУБ Engineering, Aerospace + Astronomy & Astrophysics + Geosciences, Multidisciplinary + Meteorology & Atmospheric Sciences

Аннотация: A pressure enhancement in the vicinity of Io can be created in the course of the torus plasma flow around Io due to mass loading or it can be produced by volcanic outbursts on Io. For a given magnetic flux tube crossed by Io, a pressure pulse generates two slow magnetosonic waves propagating along the tube to the southern and northern ionosphere of Jupiter. These slow waves evolve rather quickly into shocks due to a steepening mechanism with accelerated plasma flow behind the shock front. This plasma flow streaming along the Io flux tube generates a field aligned potential difference, which can reach values of 1 kV for sufficiently strong pressure pulses. Therefore, this slow mode scenario seems to contribute to the Io controlled aurora as well as to the Io controlled Jovian decameter radiation (DAM) together with the generally accepted Alfven wings model. (C) 2001 COSPAR. Published by Elsevier Science Ltd. All rights reserved.


Доп.точки доступа:
Erkaev, N.V.; Еркаев, Николай Васильевич; Semenov, V.S.; Shaidurov, V.A.; Langmayr, D.; Biernat, H.K.; Rucker, H.O.; Thomas, N. \ed.\; Coustenis, A. \ed.\; LeliwaKopysty, J. \ed.\

[Text] / H. Lammer [et al.] // Planet Space Sci. - 2006. - Vol. 54, Is. 13-14. - P1445-1456, DOI 10.1016/j.pss.2006.04.022. - Cited References: 93 . - ISSN 0032-0633РУБ Astronomy & Astrophysics

Аннотация: Atmospheric escape from the upper atmosphere of Venus is mainly influenced by the loss of hydrogen and oxygen caused by the interaction of solar radiation and particle flux with the unprotected planetary environment. Because one main aim of the ASPERA-4 particle/plasma and VEX-MAG magnetic field experiments on board of ESA's forthcoming Venus Express mission is the investigation of atmospheric erosion processes from the planet's ionosphere-exosphere environment, we study the total loss of hydrogen and oxygen and identified the efficiency of several escape mechanisms involved. For the estimation of pick up loss rates we use a gas dynamic test particle model and obtained average loss rates for H+, and O+ pick up ions of about 1 x 10(25) s(-1) and about 1.6 x 10(25) s(-1), respectively. Further, we estimate ion loss rates due to detached plasma clouds, which were observed by the pioneer Venus orbiter and may be triggered by the Kelvin-Helmholtz instability of about 0.5-1 x 10(25) s(-1). Thermal atmospheric escape processes and atmospheric loss by photo-chemically produced oxygen atoms yield negligible loss rates. Sputtering by incident pick up O+ ions give O atom loss rates in the order of about 6 x 10(24) s(-1). On the other hand, photo-chemically produced hot hydrogen atoms are a very efficient loss mechanism for hydrogen on Venus with a global average total loss rate of about 3.8 x 10(25) s(-1), which is in agreement with Donahue and Hartle [1992. Solar cycle variations in H+ and D+ densities in the Venus ionosphere: implications for escape. Geophys. Res. Lett. 12, 2449-2452] and of the same order but less than the estimated H+ ion outflow on the Venus nightside of about 7.0 x 10(25) s(-1) due to acceleration by an outward electric polarization force related to ionospheric holes by Hartle and Grebowsky [1993. Light ion flow in the nightside ionosphere of Venus. J. Geophys. Res. 98, 7437-7445]. Our study indicates that on Venus, due to its larger mass and size compared to Mars, the most relevant atmospheric escape processes of oxygen involve ions and are caused by the interaction with the solar wind. The obtained results indicate that the ratio between H/O escape to space from the Venusian upper atmosphere is about 4, and is in a much better agreement with the stoichiometrically H/O escape ratio of 2:1, which is not the case on Mars. However, a detailed analysis of the outflow of ions from the Venus upper atmosphere by the ASPERA-4 and VEX-MAG instruments aboard Venus Express will lead to more accurate atmospheric loss estimations and a better understanding of the planet's water inventory. (c) 2006 Elsevier Ltd. All rights reserved.


Доп.точки доступа:
Lammer, H.; Lichtenegger, H.I.M.; Biernat, H.K.; Erkaev, N.V.; Еркаев, Николай Васильевич; Arshukova, I.L.; Kolb, C.; Gunell, H.; Lukyanov, A.; Holmstrom, M.; Barabash, S.; Zhang, T.L.; Baumjohann, W.

[Text] / N. V. Erkaev [et al.] ; ed. H. K. Biernat // BOUNDARY LAYERS, WAVES AND NON-LINEAR DYNAMICAL PROCESSES. Ser. ADVANCES IN SPACE RESEARCH : ELSEVIER SCIENCE LTD, 2006. - Vol. 37: 35th COSPAR Scientific Assembly (JUL 18-25, 2004, Paris, FRANCE), Is. 3. - P576-580, DOI 10.1016/j.asr.2005.09.002. - Cited References: 7 . - ISBN 0273-1177РУБ Engineering, Aerospace + Astronomy & Astrophysics + Geosciences, Multidisciplinary + Meteorology & Atmospheric Sciences

Аннотация: A ratio of the maximal and minimal cross sections of the magnetic tube (contraction ratio) is a crucial parameter which affects very strongly on reflections of MHD wave pulses propagating along a narrowing magnetic flux tube. In cases of large contraction ratios of magnetospheric magnetic tubes, the wave energy flux at the ionospheric boundary can be rather small. Therefore the dissipation of the wave perturbations can be very weak for each reflection, in spite of a finite conductivity of the planet's ionosphere. The dissipation is stronger for the pulses with shorter wave scales. Because of that, Alfven wave pulses with sufficiently long wave scales have a very small energy loss for each reflection at the conducting ionosphere, and thus, they have many reflections without a noticeable decrease of their amplitude. This effect related to converging magnetic lines is dependent very strongly on the polarization of the Alfven wave. In case of a dipole magnetic field, the effect is most pronounced for wave pulses characterized by velocity and magnetic perturbations in the meridional plane. (C) 2005 COSPAR. Published by Elsevier Ltd. All rights reserved.


Доп.точки доступа:
Erkaev, N.V.; Еркаев, Николай Васильевич; Shaidurov, V.A.; Semenov, V.S.; Biernat, H.K.; Heidorn, D.; Biernat, H.K. \ed.\

[Text] / H. . Lammer [et al.] // Astron. Astrophys. - 2009. - Vol. 506, Is. 1. - P399-410, DOI 10.1051/0004-6361/200911922. - Cited References: 46. - The authors thank the anonymous referee for constructive comments and suggestions which helped to improve the paper. H. Lammer, P. Odert, M. Leitzinger, M. L. Khodachenko and A. Hanslmeier gratefully acknowledge the Austrian Fonds zur Forderung der wissenschaftlichen Forschung (FWF grant P19446) for supporting this project. M. Panchenko and M. L. Khodachenko acknowledge also the Austrian Fonds zur Forderung der wissenschaftlichen Forschung (project P20680-N16). H. Lammer, H. I. M. Lichtenegger, H. K. Biernat, Yu. N. Kulikov and N. V. Erkaev thank the AAS "Verwaltungsstelle fur Auslandsbeziehungen" and the RAS. H. Lammer, H. I. M. Lichtenegger, M. L. Khodachenko and Yu. N. Kulikov acknowledge support from the Helmholtz-Gemeinschaft as this research has been supported by the Helmholtz Association through the research alliance "Planetary Evolution and Life". H. Lammer, M. L. Khodachenko, T. Penz, and Yu. N. Kulikov also acknowledge the International Space Science Institute (ISSI; Bern, Switzerland) and the ISSI teams "Evolution of Habitable Planets" and "Evolution of Exoplanet Atmospheres and their Characterization". H. K. Biernat acknowledges additional support due to the Austrian Science Fund under project P20145-N16. The authors also acknowledge fruitful discussions during various meetings related to the Europlanet N2 activities as well as within the N2 Exoplanet discipline working group DWG 7. T. Penz and G. Micela acknowledge support by the Marie Curie Fellowship Contract No. MTKD-CT-2004-002769 of the project "The influence of stellar high radiation on planetary atmospheres". The authors also thank the Austrian Ministry bm:bwk and ASA for funding the CoRoT project. . - ISSN 0004-6361РУБ Astronomy & Astrophysics

Аннотация: Aims. We study the possible atmospheric mass loss from 57 known transiting exoplanets around F, G, K, and M-type stars over evolutionary timescales. For stellar wind induced mass loss studies, we estimate the position of the pressure balance boundary between Coronal Mass Ejection (CME) and stellar wind ram pressures and the planetary ionosphere pressure for non- or weakly magnetized gas giants at close orbits. Methods. The thermal mass loss of atomic hydrogen is calculated by a mass loss equation where we consider a realistic heating efficiency, a radius-scaling law and a mass loss enhancement factor due to stellar tidal forces. The model takes into account the temporal evolution of the stellar EUV flux by applying power laws for F, G, K, and M-type stars. The planetary ionopause obstacle, which is an important factor for ion pick-up escape from non- or weakly magnetized gas giants is estimated by applying empirical power-laws. Results. By assuming a realistic heating efficiency of about 10-25% we found that WASP-12b may have lost about 6-12% of its mass during its lifetime. A few transiting low density gas giants at similar orbital location, like WASP-13b, WASP-15b, CoRoT-1b or CoRoT-5b may have lost up to 1-4% of their initial mass. All other transiting exoplanets in our sample experience negligible thermal loss (<= 1%) during their lifetime. We found that the ionospheric pressure can balance the impinging dense stellar wind and average CME plasma flows at distances which are above the visual radius of "Hot Jupiters", resulting in mass losses <2% over evolutionary timescales. The ram pressure of fast CMEs cannot be balanced by the ionospheric plasma pressure for orbital distances between 0.02-0.1 AU. Therefore, collisions of fast CMEs with hot gas giants should result in large atmospheric losses which may influence the mass evolution of gas giants with masses
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Доп.точки доступа:
Lammer, H.; Odert, P.; Leitzinger, M.; Khodachenko, M.L.; Panchenko, M.; Kulikov, Y.N.; Zhang, T.L.; Lichtenegger, H.I.M.; Erkaev, N.V.; Еркаев, Николай Васильевич; Wuchterl, G.; Micela, G.; Penz, T.; Biernat, H.K.; Weingrill, J.; Steller, M.; Ottacher, H.; Hasiba, J.; Hanslmeier, A.; Austrian Fonds zur Forderung der wissenschaftlichen Forschung [P19446, P20680-N16]; Helmholtz Association; Austrian Science Fund [P20145-N16]; "The influence of stellar high radiation on planetary atmospheres" [MTKD-CT-2004-002769]

[Text] / V. V. Denisenko, E. V. Pomozov // Geomagn. Aeron. - 2011. - Vol. 51, Is. 7. - P866-872, DOI 10.1134/S0016793211070048. - Cited References: 13. - The work was supported by the Russian Foundation for Basic Research, project no. 09-06-91000. The authors are grateful to A.A. Namgaladze for a substantive, although not consensus-inducing, discussion of the work, as well as to colleagues from the Institute of Cosmic Research of the Austrian Academy of Sciences, with whom jointly this cycle of studies was carried out. . - ISSN 0016-7932РУБ Geochemistry & Geophysics

Аннотация: A mathematical model has been proposed for describing quasi-stationary atmospheric electric fields with approximate, but fairly accurate allowance for ionospheric conductivity. It is shown that some well-known models of electric field penetration from the Earth into the ionosphere have been deemed inadequate, though they work well in the atmosphere below 50 km. In these models, the arbitrarily specified boundary condition in the upper boundary of the atmosphere omits the existing good conductor or adds not existent conductor. The maximum possible field in our model is far less than in models where ionospheric conductivity is not taken into account, but vastly larger than in models based on the approximation with infinite Pedersen conductivity in the upper ionosphere.


Доп.точки доступа:
Pomozov, E.V.; Помозов, Егор Владимирович; Денисенко, Валерий Васильевич

[Text] / V. V. Denisenko [et al.] // Ann. Geophys. - 2008. - Vol. 26, Is. 8. - P2111-2130. - Cited References: 19. - This work is supported by grant 07-05-00135 from the Russian Foundation for Basic Research, by the Programs 16.3 and 2.16 of the Russian Academy of Sciences, and by project I.2/04 from "Osterreichischer Austauschdienst". It is also supported by the Austrian "Fonds zur Forderung der wissenschaftlichen Forschung" under projects P17100-N08 and P20145-N16. We acknowledge support by the Austrian Academy of Sciences, "Verwaltungstelle fur Auslandsbeziehungen", and the Russian Academy of Sciences. . - ISSN 0992-7689РУБ Astronomy & Astrophysics + Geosciences, Multidisciplinary + Meteorology & Atmospheric Sciences

Аннотация: A quantitative division of the ionosphere into dynamo and motor regions is performed on the base of empirical models of space distributions of ionospheric parameters. Pedersen and Hall conductivities are modified to represent an impact of acceleration of the medium because of Ampere's force. It is shown that the currents in the F(2) layer are greatly reduced for processes of a few hours duration. This reduction is in particular important for the night-side low-latitude ionosphere. The International Reference Ionosphere model is used to analyze the effect quantitatively. This model gives a second high conducting layer in the night-side low-latitude ionosphere that reduces the electric field and equatorial electrojets, but intensifies night-side currents during the short-term events. These currents occupy regions which are much wider than those of equatorial electrojets. It is demonstrated that the parameter sigma(d)=sigma(P)+sigma(H)Sigma(H)/Sigma(P) that involves the integral Pedersen and Hall conductances Sigma(P), Sigma(H) ought to be used instead of the local Cowling conductivity sigma C in calculations of the electric current density in the equatorial ionosphere. We may note that Gurevich et al. (1976) derived a parameter similar to sigma(d) for more general conditions as those which we discuss in this paper; a more detailed description of this point is given in Sect. 6. Both, sigma(d) and sigma(C), appear when a magnetic field line is near a nonconducting domain which means zero current through the boundary of this domain. The main difference between sigma(d) and sigma(C) is that sigma d definition includes the possibility for the electric current to flow along a magnetic field line in order to close all currents which go to this line from neighboring ones. The local Cowling conductivity sigma(C) corresponds to the current closure at each point of a magnetic field line. It is adequate only for a magnetic field line with constant local conductivity at the whole line when field-aligned currents do not exist because of symmetry, but sigma(C)=sigma(d) in this case. So, there is no reason to use the local Cowling conductivity while the Cowling conductance Sigma(C)=Sigma(P)+Sigma(2)(H)/Sigma(P) is a useful and well defined parameter.


Доп.точки доступа:
Denisenko, V.V.; Денисенко, Валерий Васильевич; Biernat, H.K.; Mezentsev, A.V.; Shaidurov, V.A.; Zamay, S.S.

[Text] / V. V. Denisenko [et al.] // Nat. Hazards Earth Syst. Sci. - 2008. - Vol. 8, Is. 5. - P1009-1017. - Cited References: 60. - This work is supported by grant 07-05-00135 from the Russian Foundation for Basic Research and by the Programs 16.3 and 2.16 of the Russian Academy of Sciences. Further support is due to the Austrian "Fonds zur Forderung der wissenschaftlichen Forschung" under project P20145-N16. We acknowledge support by the Austrian Academy of Sciences, "Verwaltungstelle fur Auslandsbeziehungen", and the Russian Academy of Sciences. Part of this research was done during academic visits of V. V. 'Denisenko to the Space Research Institute of the Austrian Academy of Sciences in Graz as well as during an academic visit of H. K. Biernat to the Institute of Computational Modelling of the Russian Academy of Sciences in Krasnoyarsk. . - ISSN 1561-8633РУБ Geosciences, Multidisciplinary + Meteorology & Atmospheric Sciences + Water Resources

Аннотация: The classic approach to calculate the electrostatic field penetration, from the Earth's surface into the ionosphere, is to consider the following equation del. ((sigma) over cap del Phi) =0 where (sigma) over cap and Phi are the electric conductivity and the potential of the electric field, respectively. The penetration characteristics strongly depend on the conductivities of atmosphere and ionosphere. To estimate the electrostatic field penetration up to the orbital height of DEMETER satellite (about 700 km) the role of the ionosphere must be analyzed. It is done with help of a special upper boundary condition for the atmospheric electric field. In this paper, we investigate the influence of the ionospheric conductivity on the electrostatic field penetration from the Earth's surface into the ionosphere. We show that the magnitude of the ionospheric electric field penetrated from the ground is inverse proportional to the value of the ionospheric Pedersen conductance. So its typical value in day-time is about hundred times less than in night-time.


Доп.точки доступа:
Denisenko, V.V.; Денисенко, Валерий Васильевич; Boudjada, M.Y.; Horn, M.; Pomozov, E.V.; Помозов, Егор Владимирович; Biernat, H.K.; Schwingenschuh, K.; Lammer, H.; Prattes, G.; Cristea, E.

[Text] / V. V. Denisenko, S. S. Zamai, A. V. Kitaev // Geomagn. Aeron. - 2003. - Vol. 43, Is. 6. - P680-686. - Cited References: 15 . - ISSN 0016-7932РУБ Geochemistry & Geophysics

Аннотация: The effect of viscous friction at the boundary between the plasma sheet and the solar wind on electric field generation in the plasma sheet is estimated. The boundary layer is modeled by a viscous layer with two mixing plasma flows. The distribution of the flow velocity in the inner parts of the plasma sheet outside the boundary layer is specified on the basis of experimental data. The calculated distribution of the electric potential in the plasma sheet and at the magnetopause is projected along magnetic lines onto the ionosphere. It has been indicated that, within the scope of the adopted model, viscous friction on the magnetotail flanks for an effective Reynolds number of Re = 3 x 10(3) results in an increase in the potential across the polar cap from 11 to 18 kV. In this case the maximum and minimum of the electric potential at the polar cap boundary are shifted from the nightside to the dayside. It is emphasized that the total distribution of the electric potential in the polar cap under quiet conditions results from the operation of several mechanisms of electric field generation.


Доп.точки доступа:
Zamai, S.S.; Kitaev, A.V.; Денисенко, Валерий Васильевич

[Text] / V. V. Denisenko, S. S. Zamay // Geomagn. Aeron. - 2001. - Vol. 41, Is. 1. - P91-95. - Cited References: 19 . - ISSN 0016-7932РУБ Geochemistry & Geophysics

Аннотация: A method for estimating the effect of ponderomotive forces on the distribution of large-scale electric fields and currents in the ionosphere has been proposed. A model of the ionosphere as a global conductor is used to re-calculate local values of the conductivity tensor components in such a way that the acceleration of the medium under the action of ponderomotive forces would be taken into account. A multifold decrease in the F-2-layer effective conductivity has been found for processes lasting for several hours. In this case, the contribution of the entire F layer to the integral conductivity is significantly lowered and becomes negligible for the daytime ionosphere. In the nighttime, the F-layer contribution to the integral Pedersen conductivity several times exceeds the E-layer contribution.


Доп.точки доступа:
Zamay, S.S.; Денисенко, Валерий Васильевич

[Text] / V. V. DENISENKO, S. S. ZAMAY // Planet Space Sci. - 1992. - Vol. 40, Is. 7. - P941-952, DOI 10.1016/0032-0633(92)90134-A. - Cited References: 47 . - ISSN 0032-0633РУБ Astronomy & Astrophysics

Аннотация: A model of the ionosphere as a global conductor is used to examine synchronous variations of electric fields and currents at high and low latitudes. The special form of a boundary value problem and a multigrid numerical method permit investigation of auroral field penetration to the equator. A model of field-aligned currents and conductivities for expansion and recovery phases of a substorm are suggested, which are in accordance with empirical models and with theory of field-aligned current dynamics. Electric field distributions near the equator, which were obtained as a result of calculations, are in accordance with observations during substorms. It is shown that the contribution of high latitude sources to low latitude electric fields and currents during quiet-time periods is comparable with that given by dynamo fields. The nature of the post-sunset peak of the zonal electric field at the equator and seasonal variations of this peak are explained.


Доп.точки доступа:
ZAMAY, S.S.; Денисенко, Валерий Васильевич

[Текст] / V. V. DENISENKO, S. S. ZAMAI // Geomagn. Aeron. - 1991. - Vol. 31, Is. 3. - С. 539-542. - Cited References: 11 . - ISSN 0016-7940РУБ Geochemistry & Geophysics


Доп.точки доступа:
ZAMAI, S.S.; Денисенко, Валерий Васильевич