[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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ИВМ СО РАН : 660036, Красноярск, Академгородок, 50, стр.44
Доп.точки доступа:
Erkaev, N.V.; Еркаев, Николай Васильевич; Biernat, H.K.; Аршукова И.Л.
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В3
A80
A80
Instability of the magnetopause with a finite curvature radius and velocity shear
В3
I70
I70
Investigation of MHD slow shocks propagating along the Io flux tube
[Text] : статья / N.V. Erkaev [et al.] // International journal of geomagnetism and aeronomy. - 2002. - Vol. 3, № 1. - p. 67-76
Аннотация: One aspect of the Io-Jupiter interaction studied by many authors is the generation of Alfv_en waves by Io moving in the magnetized plasma. In our study, we focus on an additional mechanism of the interaction between Io and Jupiter based on MHD slow shocks propagating from Io toward Jupiter along a magnetic ux tube. These MHD slow shocks are produced by plasma ow injected by Io, which is considered as a source of ionized particles. The propagation of the slow shocks is calculated along a given magnetic ux tube from Io to Jupiter. The total pressure is assumed to be a known function of the distance measured along the tube. It is determined as the magnetic pressure corresponding to the undisturbed Jovian magnetic field calculated in a dipole approximation. The material coordinates are used to describe the plasma ow along the magnetic tube. The peculiarity of this problem stems from the fact that the total pressure increases by a factor of 105, whereas the cross section of the magnetic ux tube decreases by a factor of 300. The result is that the plasma velocity after the shock front substantially increases toward Jupiter with increasing magnetic pressure. The electric potential difference along the magnetic field is estimated, which is produced by the accelerated plasma ow propagating with the MHD slow shocks.
http://icm.krasn.ru/refextra.php?id=2436,
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Держатели документа:
ИВМ СО РАН : 660036, Красноярск, Академгородок, 50, стр.44
Доп.точки доступа:
Erkaev, N.V.; Еркаев, Николай Васильевич; Semenov, V.S.; Семенов В. С.; Shaidurov, V.A.; Шайдуров В.А.; Langmayr, D.; Biernat, H.K.; Rucker, H.O.
Аннотация: One aspect of the Io-Jupiter interaction studied by many authors is the generation of Alfv_en waves by Io moving in the magnetized plasma. In our study, we focus on an additional mechanism of the interaction between Io and Jupiter based on MHD slow shocks propagating from Io toward Jupiter along a magnetic ux tube. These MHD slow shocks are produced by plasma ow injected by Io, which is considered as a source of ionized particles. The propagation of the slow shocks is calculated along a given magnetic ux tube from Io to Jupiter. The total pressure is assumed to be a known function of the distance measured along the tube. It is determined as the magnetic pressure corresponding to the undisturbed Jovian magnetic field calculated in a dipole approximation. The material coordinates are used to describe the plasma ow along the magnetic tube. The peculiarity of this problem stems from the fact that the total pressure increases by a factor of 105, whereas the cross section of the magnetic ux tube decreases by a factor of 300. The result is that the plasma velocity after the shock front substantially increases toward Jupiter with increasing magnetic pressure. The electric potential difference along the magnetic field is estimated, which is produced by the accelerated plasma ow propagating with the MHD slow shocks.
http://icm.krasn.ru/refextra.php?id=2436,
Полный текст
Держатели документа:
ИВМ СО РАН : 660036, Красноярск, Академгородок, 50, стр.44
Доп.точки доступа:
Erkaev, N.V.; Еркаев, Николай Васильевич; Semenov, V.S.; Семенов В. С.; Shaidurov, V.A.; Шайдуров В.А.; Langmayr, D.; Biernat, H.K.; Rucker, H.O.
В3
M66
M66
Numerical Simulation the Periodic Operating Regime of HRE with MHD Control
[Text]. - Electronic text data (73 Kb)
. - Режим доступа: http://icm.krasn.ru/refextra.php?id=1515. - Электрон. версия печ. публикации . - Режим доступа: http://library.krasn.ru/trudy/2000/1515lab23eng_28.pdf (Полный текст) : статья / A.N. Mierau, V.A. Derevyanko, A.N. Vasilyev. - Electronic text data (73 Kb) // X International Conference on the Methods of Aerophysical Research. - Novosibirsk, 2000. - Part III. - p. 143-149
Аннотация: Nowadays both in Russia and abroad active research has been conducted on developing perspective hypersonic aerospace aircraft. The developing of such aircraft would allow to essentially expand aircraft possibilities and to reduce delivery cost of goods to the near-earth orbit. In many countries of the world there are programs of creation of hypersonic aircraft such as: HOTOL in Great Britain, NASP in USA, HERMES in France. One of key while conducting these projects is the creation of a hypersonic ramjet engine having necessary propulsive, mass and dimensional characteristics with all altitude range and flight velocities of an aircraft. The basic difficulties, in development of such engine types are caused by substantial of deterioration of quality of fuel mixture with an oxidant under supersonic flow velocities in the combustion chamber, which results in decrease of an engine efficiency and deterioration of its propulsion. To increase the efficiency of HRE with the supersonic flow velocity in the combustion chamber the authors offered MHD control of gas flow in the channel HRE based on creation in a stream of local plasma areas with temperature 104 K interacting with an external magnetic field [1], [2]. The work presents investigation results for the structure of non-stationary gas-dynamic flow in the channel HRE with MHD - control. It also describes the calculation of propulsion performance characteristics of the given engine on the basis of mathematical simulation of processes, which take place in the channel of an engine. Thee work objective was the research of non-stationary periodic flow with heat application in the tract HRE with MHD - control on the basis of mathematical modeling of processes which take place in the channel of an engine and the calculation of propulsion performance characteristics of an engine. In the work the model HRE including the air intake, MHD - channel and nozzle was considered. The MHD - channel is made of two flat electrodes and sidewalls from a dielectric. The local constant flow heat permitting to create periodical local plasma areas (T- layer) is provided with the systems of initiation the constant magnetic field in the volume of the channel is ensured with an external magnetic system.
http://icm.krasn.ru/refextra.php?id=1515,
Полный текст
Держатели документа:
ИВМ СО РАН : 660036, Красноярск, Академгородок, 50, стр.44
Доп.точки доступа:
Derevyanko, V.A.; Деревянко, Валерий Александрович; Vasilyev, A.N.; Васильев А.Н.
. - Режим доступа: http://icm.krasn.ru/refextra.php?id=1515. - Электрон. версия печ. публикации . - Режим доступа: http://library.krasn.ru/trudy/2000/1515lab23eng_28.pdf (Полный текст) : статья / A.N. Mierau, V.A. Derevyanko, A.N. Vasilyev. - Electronic text data (73 Kb) // X International Conference on the Methods of Aerophysical Research. - Novosibirsk, 2000. - Part III. - p. 143-149
Аннотация: Nowadays both in Russia and abroad active research has been conducted on developing perspective hypersonic aerospace aircraft. The developing of such aircraft would allow to essentially expand aircraft possibilities and to reduce delivery cost of goods to the near-earth orbit. In many countries of the world there are programs of creation of hypersonic aircraft such as: HOTOL in Great Britain, NASP in USA, HERMES in France. One of key while conducting these projects is the creation of a hypersonic ramjet engine having necessary propulsive, mass and dimensional characteristics with all altitude range and flight velocities of an aircraft. The basic difficulties, in development of such engine types are caused by substantial of deterioration of quality of fuel mixture with an oxidant under supersonic flow velocities in the combustion chamber, which results in decrease of an engine efficiency and deterioration of its propulsion. To increase the efficiency of HRE with the supersonic flow velocity in the combustion chamber the authors offered MHD control of gas flow in the channel HRE based on creation in a stream of local plasma areas with temperature 104 K interacting with an external magnetic field [1], [2]. The work presents investigation results for the structure of non-stationary gas-dynamic flow in the channel HRE with MHD - control. It also describes the calculation of propulsion performance characteristics of the given engine on the basis of mathematical simulation of processes, which take place in the channel of an engine. Thee work objective was the research of non-stationary periodic flow with heat application in the tract HRE with MHD - control on the basis of mathematical modeling of processes which take place in the channel of an engine and the calculation of propulsion performance characteristics of an engine. In the work the model HRE including the air intake, MHD - channel and nozzle was considered. The MHD - channel is made of two flat electrodes and sidewalls from a dielectric. The local constant flow heat permitting to create periodical local plasma areas (T- layer) is provided with the systems of initiation the constant magnetic field in the volume of the channel is ensured with an external magnetic system.
http://icm.krasn.ru/refextra.php?id=1515,
Полный текст
Держатели документа:
ИВМ СО РАН : 660036, Красноярск, Академгородок, 50, стр.44
Доп.точки доступа:
Derevyanko, V.A.; Деревянко, Валерий Александрович; Vasilyev, A.N.; Васильев А.Н.
The Numerical Solution of the Boundary Function Inverse Problem for the Tidal Models
[Text] : статья / E.D. Karepova, E. Dementyeva // Parallel Computing Technologies. - 2013. - Vol. 8236. - p. 345-354
Кл.слова (ненормированные):
data assimilation problem -- finite elements method and high performance computation
Аннотация: The problem of propagation of long waves in a domain of an arbitrary form with the sufficiently smooth boundary on a sphere is considered. The boundary consists of “solid” parts passing along the coastline and “open liquid” parts passing through the water area. In general case the influence of the ocean through an open boundary is unknown and must be found together with components of a velocity vector and free surface elevation. For this purpose we use observation data of free surface elevation given only on a part of an “open liquid” boundary. We solve our ill-posed inverse problem by an approach based on the optimal control methods and adjoint equations theory.
Полный текст
Доп.точки доступа:
Dementyeva, E.V.; Дементьева, Екатерина Васильевна; Карепова, Евгения Дмитриевна
Кл.слова (ненормированные):
data assimilation problem -- finite elements method and high performance computation
Аннотация: The problem of propagation of long waves in a domain of an arbitrary form with the sufficiently smooth boundary on a sphere is considered. The boundary consists of “solid” parts passing along the coastline and “open liquid” parts passing through the water area. In general case the influence of the ocean through an open boundary is unknown and must be found together with components of a velocity vector and free surface elevation. For this purpose we use observation data of free surface elevation given only on a part of an “open liquid” boundary. We solve our ill-posed inverse problem by an approach based on the optimal control methods and adjoint equations theory.
Полный текст
Доп.точки доступа:
Dementyeva, E.V.; Дементьева, Екатерина Васильевна; Карепова, Евгения Дмитриевна
Scattering and absorption of resonant radiation in an expanding sphere
/ N.I. Kosarev, N.Y. Shaparev // J. Phys. B-At. Mol. Opt. Phys. - 2012. - Vol. 45, Is. 16. - Ст. 165003, DOI 10.1088/0953-4075/45/16/165003. - Cited References: 12
. - ISSN 0953-4075
РУБ Optics + Physics, Atomic, Molecular & Chemical
Аннотация: The radiative transfer in a freely expanding gaseous sphere, illuminated by external radiation, has been numerically studied. The absorption coefficient, spectral and spatial characteristics of the absorbed and scattered radiations, and the radial dependences of excited atomic concentration have been determined, and the influence of the optical thickness and the atomic radial expansion velocity on them has been investigated.
Доп.точки доступа:
Shaparev, N.Ya.; Шапарев, Николай Якимович; Косарев Н.И.
Аннотация: The radiative transfer in a freely expanding gaseous sphere, illuminated by external radiation, has been numerically studied. The absorption coefficient, spectral and spatial characteristics of the absorbed and scattered radiations, and the radial dependences of excited atomic concentration have been determined, and the influence of the optical thickness and the atomic radial expansion velocity on them has been investigated.
Доп.точки доступа:
Shaparev, N.Ya.; Шапарев, Николай Якимович; Косарев Н.И.
Scaling of the inner electron diffusion region in collisionless magnetic reconnection
/ A. Divin [et al.] // J. Geophys. Res-Space Phys. - 2012. - Vol. 117. - Ст. A06217, DOI 10.1029/2011JA017464. - Cited References: 43. - The present work is supported partially by the Onderzoekfonds KU Leuven (Research Fund KU Leuven), by the NASA MMS grant NNX08AO84G and by the European Commission's Seventh Framework Programme (FP7/2007-2013) under the grant agreement 263340 (SWIFF project, www. swiff. eu) and 269198 - Geoplasmas (Marie Curie International Research Staff Exchange Scheme). Additional support is provided by RFBR grants 09-05-91000-ANF-a, 12-05-00152-a and 12-05-00918-a, Austrian Science Fund project T193-N16 and by SPSU grants 11.38.47.2011 and 11.38.84.2012. The simulations were conducted on the resources of the Vlaams Supercomputer Centrum (VSC) at the Katholieke Universiteit Leuven. The authors wish to thank the reviewers for their comments that helped to improve the manuscript.
. - ISSN 2169-9380
РУБ Astronomy & Astrophysics
Аннотация: The Sweet-Parker analysis of the inner electron diffusion region of collisionless magnetic reconnection is presented. The study includes charged particles motion near the X-line and an appropriate approximation of the off-diagonal term for the electron pressure tensor. The obtained scaling shows that the width of the inner electron diffusion region is equal to the electron inertial length, and that electrons are accelerated up to the electron Alfven velocity in X-line direction. The estimated effective plasma conductivity is based on the electron gyrofrequency rather than the binary collision frequency, and gives the extreme (minimal) value of the plasma conductivity similar to Bohm diffusion. The scaling properties are verified by means of Particle-in-Cell simulations. An ad hoc parameter needs to be introduced to the scaling relations in order to better match the theory and simulations.
Доп.точки доступа:
Divin, A.; Lapenta, G.; Markidis, S.; Semenov, V.S.; Erkaev, N.V.; Еркаев, Николай Васильевич; Korovinskiy, D.B.; Biernat, H.K.
Аннотация: The Sweet-Parker analysis of the inner electron diffusion region of collisionless magnetic reconnection is presented. The study includes charged particles motion near the X-line and an appropriate approximation of the off-diagonal term for the electron pressure tensor. The obtained scaling shows that the width of the inner electron diffusion region is equal to the electron inertial length, and that electrons are accelerated up to the electron Alfven velocity in X-line direction. The estimated effective plasma conductivity is based on the electron gyrofrequency rather than the binary collision frequency, and gives the extreme (minimal) value of the plasma conductivity similar to Bohm diffusion. The scaling properties are verified by means of Particle-in-Cell simulations. An ad hoc parameter needs to be introduced to the scaling relations in order to better match the theory and simulations.
Доп.точки доступа:
Divin, A.; Lapenta, G.; Markidis, S.; Semenov, V.S.; Erkaev, N.V.; Еркаев, Николай Васильевич; Korovinskiy, D.B.; Biernat, H.K.
Accelerated magnetosheath flows caused by IMF draping: Dependence on latitude
/ N. V. Erkaev [et al.] // Geophys. Res. Lett. - 2012. - Vol. 39. - Ст. L01103, DOI 10.1029/2011GL050209. - Cited References: 16. - This work was done while NVE 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 CJF was supported by NASA grants NNX10AQ29G and NNX08AD11G.
. - ISSN 0094-8276
РУБ Geosciences, Multidisciplinary
Аннотация: In previous work we used a semi-analytical treatment to describe accelerated magnetosheath flows caused by the draping of interplanetary magnetic field (IMF) lines around the magnetosphere. Here, we use the same approach, i.e., modeling the magnetic field lines as elastic strings, to examine how the magnetic tension force, one of the two agents responsible for producing these flows, varies along field lines away from the equatorial plane. The bend in the field line caused by the draping mechanism propagates as two oppositely-directed waves to higher latitudes. For a due northward IMF - the case we consider here - these propagate symmetrically north/south of the equatorial plane. As a result, a two-peaked latitude velocity profile develops as we go further downtail and the velocity peaks migrate along the magnetic field line to higher latitudes. We examine this velocity-profile for two Alfven Mach numbers (M-A = 8 and 3), representative of conditions in the solar wind at 1 AU ("normal" solar wind and solar transients). Qualitatively, the picture is the same but quantitatively there are important differences: (i) the flows reach higher values for the lower M-A (maximum V/V-SW = 1.6) than for the higher M-A (V/V-SW = 1.3); (ii) asymptotic values are reached farther downstream of the dawn-dusk terminator for the lower M-A (similar to-50 R-E vs -15 R-E); (iii) For the lower M-A the highest speeds are reached away from the equatorial plane. We predict two channels of fast magnetosheath flow next to the magnetopause at off-equatorial latitudes that exceed the solar wind speed. Citation: Erkaev, N. V., C. J. Farrugia, A. V. Mezentsev, R. B. Torbert, and H. K. Biernat (2012), Accelerated magnetosheath flows caused by IMF draping: Dependence on latitude, Geophys. Res. Lett., 39, L01103, doi:10.1029/2011GL050209.
Полный текст
Доп.точки доступа:
Erkaev, N.V.; Еркаев, Николай Васильевич; Farrugia, C.J.; Mezentsev, A.V.; Torbert, R.B.; Biernat, H.K.
Аннотация: In previous work we used a semi-analytical treatment to describe accelerated magnetosheath flows caused by the draping of interplanetary magnetic field (IMF) lines around the magnetosphere. Here, we use the same approach, i.e., modeling the magnetic field lines as elastic strings, to examine how the magnetic tension force, one of the two agents responsible for producing these flows, varies along field lines away from the equatorial plane. The bend in the field line caused by the draping mechanism propagates as two oppositely-directed waves to higher latitudes. For a due northward IMF - the case we consider here - these propagate symmetrically north/south of the equatorial plane. As a result, a two-peaked latitude velocity profile develops as we go further downtail and the velocity peaks migrate along the magnetic field line to higher latitudes. We examine this velocity-profile for two Alfven Mach numbers (M-A = 8 and 3), representative of conditions in the solar wind at 1 AU ("normal" solar wind and solar transients). Qualitatively, the picture is the same but quantitatively there are important differences: (i) the flows reach higher values for the lower M-A (maximum V/V-SW = 1.6) than for the higher M-A (V/V-SW = 1.3); (ii) asymptotic values are reached farther downstream of the dawn-dusk terminator for the lower M-A (similar to-50 R-E vs -15 R-E); (iii) For the lower M-A the highest speeds are reached away from the equatorial plane. We predict two channels of fast magnetosheath flow next to the magnetopause at off-equatorial latitudes that exceed the solar wind speed. Citation: Erkaev, N. V., C. J. Farrugia, A. V. Mezentsev, R. B. Torbert, and H. K. Biernat (2012), Accelerated magnetosheath flows caused by IMF draping: Dependence on latitude, Geophys. Res. Lett., 39, L01103, doi:10.1029/2011GL050209.
Полный текст
Доп.точки доступа:
Erkaev, N.V.; Еркаев, Николай Васильевич; Farrugia, C.J.; Mezentsev, A.V.; Torbert, R.B.; Biernat, H.K.
Numerical simulation of supersonic flows in a channel
/ V.V. Shaidurov, G.I. Shchepanovskaya, V.M. Yakubovich // Russ. J. Numer. Anal. Math. Model. - 2012. - Vol. 27, Is. 6. - pp. 585-601, DOI 10.1515/rnam-2012-0034. - Cited References: 18. - The work was supported by the Russian Foundation for Basic Research (11-01-00224) and by the TRISTAM International project.
. - ISSN 0927-6467
РУБ Engineering, Multidisciplinary + Mathematics, Applied
Аннотация: An algorithm for numerical solution of Navier-Stokes equations for two-dimensional motion of a viscous heat-conducting gas is proposed in the paper. The discretization of the equations is performed by a combination of the method of trajectories for the substantive derivative and the finite element method with piecewise-bilinear basis functions for other summands. Results of numerical study of the supersonic flow structure are presented for a flat channel in its step expansion zone for a wide range of Mach and Reynolds numbers. Velocity and pressure fields are investigated, the vortex structure of the circulation flow is studied in the domain after the step.
Доп.точки доступа:
Shaidurov, V.V.; Шайдуров, Владимир Викторович; Shchepanovskaya, G.I.; Щепановская, Галина Ивановна; Yakubovich, M.V.; Якубович, Максим Викторович
Аннотация: An algorithm for numerical solution of Navier-Stokes equations for two-dimensional motion of a viscous heat-conducting gas is proposed in the paper. The discretization of the equations is performed by a combination of the method of trajectories for the substantive derivative and the finite element method with piecewise-bilinear basis functions for other summands. Results of numerical study of the supersonic flow structure are presented for a flat channel in its step expansion zone for a wide range of Mach and Reynolds numbers. Velocity and pressure fields are investigated, the vortex structure of the circulation flow is studied in the domain after the step.
Доп.точки доступа:
Shaidurov, V.V.; Шайдуров, Владимир Викторович; Shchepanovskaya, G.I.; Щепановская, Галина Ивановна; Yakubovich, M.V.; Якубович, Максим Викторович
Scattering of resonant radiation in an expanding sphere
/ N. Y. Shaparev // 2012 INTERNATIONAL CONFERENCE ON OPTOELECTRONICS AND MICROELECTRONICS (ICOM) : IEEE COMPUTER SOC, 2012. - International Conference on Optoelectronics and Microelectronics (ICOM) (AUG 23-25, 2012, Changchun, PEOPLES R CHINA). - pp. 337-341. - Cited References: 12
. - ISBN 978-1-4673-2639-1
РУБ Engineering, Electrical & Electronic + Nanoscience & Nanotechnology + Optics
Аннотация: The radiative transfer in a freely expanding gaseous sphere, illuminated by external radiation, has been studied numerically. The absorption coefficient, spectral and spatial characteristics of the absorbed and scattered radiation, the radial dependences of excited atomic concentration have been determined, the influence of the optical thickness and the atomic radial expansion velocity on them have been investigated.
РИНЦ
Доп.точки доступа:
Шапарев, Николай Якимович
Аннотация: The radiative transfer in a freely expanding gaseous sphere, illuminated by external radiation, has been studied numerically. The absorption coefficient, spectral and spatial characteristics of the absorbed and scattered radiation, the radial dependences of excited atomic concentration have been determined, the influence of the optical thickness and the atomic radial expansion velocity on them have been investigated.
РИНЦ
Доп.точки доступа:
Шапарев, Николай Якимович
Engineering, Electrical & Electronic
S53
S53
Reduced Absorption of Resonance Radiation in Expanding Gas
/ N.Y. Shaparev // 2012 INTERNATIONAL CONFERENCE ON OPTOELECTRONICS AND MICROELECTRONICS (ICOM) : IEEE COMPUTER SOC, 2012. - International Conference on Optoelectronics and Microelectronics (ICOM) (AUG 23-25, 2012, Changchun, PEOPLES R CHINA). - pp. 342-345. - Cited References: 14
. - ISBN 978-1-4673-2639-1
РУБ Engineering, Electrical & Electronic + Nanoscience & Nanotechnology + Optics
Аннотация: The paper deals with absorption of resonance and continuum radiation in an expanding gaseous sphere. For self-similar expansion, a probability of radiation to be transmitted is studied depending on the velocity gradient and optical thickness. It is shown that an optically thick medium grows thinner with the velocity gradient.
РИНЦ
Доп.точки доступа:
Шапарев, Николай Якимович
Рубрики:
SCORPII
Кл.слова (ненормированные):
line shapes -- widths -- emission -- absorption -- scattering of electromagnetic radiationr -- radiative processes -- solar radiation
SCORPII
Кл.слова (ненормированные):
line shapes -- widths -- emission -- absorption -- scattering of electromagnetic radiationr -- radiative processes -- solar radiation
Аннотация: The paper deals with absorption of resonance and continuum radiation in an expanding gaseous sphere. For self-similar expansion, a probability of radiation to be transmitted is studied depending on the velocity gradient and optical thickness. It is shown that an optically thick medium grows thinner with the velocity gradient.
РИНЦ
Доп.точки доступа:
Шапарев, Николай Якимович
Seismic inhomogeneities in the upper mantle beneath the Siberian craton (Meteorite profile)
/ V.D. Suvorov [et al.] // Russian Geology and Geophysics. - 2013. - Vol. 54, Is. 9. - pp. 1108-1120, DOI 10.1016/j.rgg.2013.07.023
. - ISSN 1068-7971
Аннотация: The upper-mantle structure was studied from first-arrival data along the Meteorite profile, run using underground nuclear explosions. Unlike the layered, slightly inhomogeneous models in the previous works, emphasis was laid on lateral inhomogeneity at the minimum possible number of abrupt seismic boundaries. We used forward ray tracing of the traveltimes of refracted and overcritical reflected waves. The model obtained is characterized by considerable velocity variations, from 7.7 km/s in the Baikal Rift Zone to 8.0-8.45 km/s beneath the Tunguska syneclise. A layer of increased velocity (up to 8.5-8.6 km/s), 30-80 km thick, is distinguished at the base of seismic lithosphere. The depth of the layer top varies from 120 km in the northern Siberian craton to 210 km in its southeastern framing. It has been shown that, with crustal density anomalies excluded, the reduced gravity field is consistent with the upper-mantle velocity model. В© 2013.
Scopus,
Полный текст
Доп.точки доступа:
Suvorov, V.D.; Mel'nik, E.A.; Mishen'kina, Z.R.; Pavlov, E.V.; Kochnev, V.A.; Кочнев, Владимир Алексеевич
Аннотация: The upper-mantle structure was studied from first-arrival data along the Meteorite profile, run using underground nuclear explosions. Unlike the layered, slightly inhomogeneous models in the previous works, emphasis was laid on lateral inhomogeneity at the minimum possible number of abrupt seismic boundaries. We used forward ray tracing of the traveltimes of refracted and overcritical reflected waves. The model obtained is characterized by considerable velocity variations, from 7.7 km/s in the Baikal Rift Zone to 8.0-8.45 km/s beneath the Tunguska syneclise. A layer of increased velocity (up to 8.5-8.6 km/s), 30-80 km thick, is distinguished at the base of seismic lithosphere. The depth of the layer top varies from 120 km in the northern Siberian craton to 210 km in its southeastern framing. It has been shown that, with crustal density anomalies excluded, the reduced gravity field is consistent with the upper-mantle velocity model. В© 2013.
Scopus,
Полный текст
Доп.точки доступа:
Suvorov, V.D.; Mel'nik, E.A.; Mishen'kina, Z.R.; Pavlov, E.V.; Kochnev, V.A.; Кочнев, Владимир Алексеевич
The spectrum of resonant laser radiation to decelerate ions in an expanding ultracold plasma
/ N.Y. Shaparev // Laser Physics Letters. - 2013. - Vol. 10, Is. 8. - Ст. 085501, DOI 10.1088/1612-2011/10/8/085501
. - ISSN 1612-2011
Аннотация: We analyze the resonance absorption spectrum of ions in an expanding ultracold spherical plasma. It is shown that the spectrum width is controlled by the highest expansion velocity at the sphere boundary. As the expansion velocity grows, the initial optical thickness of the medium decreases and the medium becomes transparent. We suggest broadband laser radiation in the red absorption spectrum of ions be used to decelerate ions in an expanding plasma in order to achieve crystallization. В© 2013 Astro Ltd.
Scopus
Доп.точки доступа:
Shaparev, N.Ya.; Шапарев, Николай Якимович
Аннотация: We analyze the resonance absorption spectrum of ions in an expanding ultracold spherical plasma. It is shown that the spectrum width is controlled by the highest expansion velocity at the sphere boundary. As the expansion velocity grows, the initial optical thickness of the medium decreases and the medium becomes transparent. We suggest broadband laser radiation in the red absorption spectrum of ions be used to decelerate ions in an expanding plasma in order to achieve crystallization. В© 2013 Astro Ltd.
Scopus
Доп.точки доступа:
Shaparev, N.Ya.; Шапарев, Николай Якимович
Transfer of resonance radiation in an expanding sphere
[Text] / N.I. Kosarev, N.Y. Shaparev // J. Phys. B-At. Mol. Opt. Phys. - 2011. - Vol. 44, Is. 19. - Ст. 195402, DOI 10.1088/0953-4075/44/19/195402. - Cited References: 17
. - ISSN 0953-4075
РУБ Optics + Physics, Atomic, Molecular & Chemical
Аннотация: Imprisonment of resonant radiation in an expanding sphere on the basis of the numerical solution of the rate balance equation for excited atoms and the transfer resonance radiation equation is investigated. Calculations of the escape factor for sphere at Doppler form of absorption and scattering profiles are executed. The effect of spectral shift of the absorption (emission) profile relative to the stationary one due to expansion of the medium is taken into account for the case when differential motion is described by velocity that varies linearly with the radius. The behaviour of the escape factor for the sphere is compared with the Sobolev theory. The numerical date for time dependence of intensity of afterglow and contour of the spectral line of leaving outside resonance radiation and spatial distribution of the excited atomic concentration are submitted as well.
Доп.точки доступа:
Shaparev, N.Ya.; Шапарев, Николай Якимович; Косарев Н.И.
Рубрики:
PLASMAS
PLASMAS
Аннотация: Imprisonment of resonant radiation in an expanding sphere on the basis of the numerical solution of the rate balance equation for excited atoms and the transfer resonance radiation equation is investigated. Calculations of the escape factor for sphere at Doppler form of absorption and scattering profiles are executed. The effect of spectral shift of the absorption (emission) profile relative to the stationary one due to expansion of the medium is taken into account for the case when differential motion is described by velocity that varies linearly with the radius. The behaviour of the escape factor for the sphere is compared with the Sobolev theory. The numerical date for time dependence of intensity of afterglow and contour of the spectral line of leaving outside resonance radiation and spatial distribution of the excited atomic concentration are submitted as well.
Доп.точки доступа:
Shaparev, N.Ya.; Шапарев, Николай Якимович; Косарев Н.И.
Kinetic Alfven wave instability in a Lorentzian dusty magnetoplasma
[Text] / N. Rubab [et al.] // Phys. Plasmas. - 2010. - Vol. 17, Is. 10. - Ст. 103704, DOI 10.1063/1.3491336. - Cited References: 54. - This work is funded by the Higher Education Commission of Pakistan under the HEC-Overseas scholarship program Grant No. Ref: 1-1/PM OS /Phase-II/Batch-I/Austria/2007/. Part of this work was done while N. V. Erkaev was at the Space Research Institute of the Austrian Academy of Sciences in Graz. This work is also supported due to the RFBR Grant No. 09-05-91000-ANF-a. Further support is due to the "Austrian Fonds zur Forderung der Wissenschaftlichen Forschung" under Grant No. P20145-N16.
. - ISSN 1070-664X
РУБ Physics, Fluids & Plasmas
Аннотация: This study presents a theoretical approach to analyze the influence of kappa distributed streaming ions and magnetized electrons on the plasma wave propagation in the presence of dust by employing two-potential theory. In particular, analytical expressions under certain conditions are derived for various modes of propagation comprising of kinetic Alfven wave streaming instability, two stream instability, and dust acoustic and whistler waves. A dispersion relation for kinetic Alfven-like streaming instability has been derived. The effects of dust particles and Lorentzian index on the growth rates and the threshold streaming velocity for the excitation of the instability are examined. The streaming velocity is observed to be destabilizing for slow motion and stabilizing for fast streaming motions. It is also observed that the presence of magnetic field and superthermal particles hinders the growth rate of instability. Possible applications to various space and astrophysical situations are discussed. (C) 2010 American Institute of Physics. [doi:10.1063/1.3491336]
Доп.точки доступа:
Rubab, N.; Erkaev, N.V.; Еркаев, Николай Васильевич; Langmayr, D.; Biernat, H.K.
Рубрики:
MAXWELLIAN DISTRIBUTION-FUNCTIONS
FREQUENCY ELECTROMAGNETIC-WAVES
SOLAR-WIND
CHARGE FLUCTUATION
2-STREAM INSTABILITIES
ELECTROSTATIC MODES
SPACE PLASMAS
ION PLASMA
TEMPERATURE
PROPAGATION
MAXWELLIAN DISTRIBUTION-FUNCTIONS
FREQUENCY ELECTROMAGNETIC-WAVES
SOLAR-WIND
CHARGE FLUCTUATION
2-STREAM INSTABILITIES
ELECTROSTATIC MODES
SPACE PLASMAS
ION PLASMA
TEMPERATURE
PROPAGATION
Аннотация: This study presents a theoretical approach to analyze the influence of kappa distributed streaming ions and magnetized electrons on the plasma wave propagation in the presence of dust by employing two-potential theory. In particular, analytical expressions under certain conditions are derived for various modes of propagation comprising of kinetic Alfven wave streaming instability, two stream instability, and dust acoustic and whistler waves. A dispersion relation for kinetic Alfven-like streaming instability has been derived. The effects of dust particles and Lorentzian index on the growth rates and the threshold streaming velocity for the excitation of the instability are examined. The streaming velocity is observed to be destabilizing for slow motion and stabilizing for fast streaming motions. It is also observed that the presence of magnetic field and superthermal particles hinders the growth rate of instability. Possible applications to various space and astrophysical situations are discussed. (C) 2010 American Institute of Physics. [doi:10.1063/1.3491336]
Доп.точки доступа:
Rubab, N.; Erkaev, N.V.; Еркаев, Николай Васильевич; Langmayr, D.; Biernat, H.K.
Joint unidirectional motion of two viscous heat-conducting fluids in a tube
[Text] / V.K. Andreev // J. Appl. Mech. Tech. Phys. - 2010. - Vol. 51, Is. 4. - pp. 497-509, DOI 10.1007/s10808-010-0066-2. - Cited References: 6. - This work was supported by the Russian Foundation for Basic Research (Grant No. 08-01-00762) and Interdisciplinary Integration Project of the Siberian Division of the Russian Academy of Science No. 65.
. - ISSN 0021-8944
РУБ Mechanics + Physics, Applied
Аннотация: This paper studies an invariant solution of the problem of joint motion of two heat-conducting viscous immiscible fluids which have a common interface in a cylindrical tube under an unsteady pressure gradient. The problem reduces to a coupled initial-boundary-value problem for parabolic equations. A priori estimates of velocity and temperature perturbations are obtained. The steady state of the system is determined, and it is proved that if, in one of the fluids, the pressure gradient rapidly approaches zero, the perturbations of all quantities tend to zero. It is shown that if the pressure gradient has a nonzero limit, the solution reaches a steady state. In this case, the velocity field in the limit is the same as in conjugate Poiseuille flow, and the temperature is represented as a polynomial of the fourth order on the radial coordinate.
Доп.точки доступа:
Андреев, Виктор Константинович
Аннотация: This paper studies an invariant solution of the problem of joint motion of two heat-conducting viscous immiscible fluids which have a common interface in a cylindrical tube under an unsteady pressure gradient. The problem reduces to a coupled initial-boundary-value problem for parabolic equations. A priori estimates of velocity and temperature perturbations are obtained. The steady state of the system is determined, and it is proved that if, in one of the fluids, the pressure gradient rapidly approaches zero, the perturbations of all quantities tend to zero. It is shown that if the pressure gradient has a nonzero limit, the solution reaches a steady state. In this case, the velocity field in the limit is the same as in conjugate Poiseuille flow, and the temperature is represented as a polynomial of the fourth order on the radial coordinate.
Доп.точки доступа:
Андреев, Виктор Константинович
Hall magnetohydrodynamic effects for current sheet flapping oscillations related to the magnetic double gradient mechanism
[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 1070-664X
РУБ 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.
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.
Some new approaches to solving Navier-Stokes equations for viscous heat-conducting gas
/ V. V. Shaydurov, G. I. Shchepanovskaya, M. V. Yakubovich // Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics). - 2013. - Vol. 8236 LNCS: 5th International Conference on Numerical Analysis and Applications, NAA 2012 (15 June 2013 through 20 June 2013, Lozenetz. - P122-131, DOI 10.1007/978-3-642-41515-9_11
. -
Кл.слова (ненормированные):
finite element method -- Navier-Stokes equations -- numerical modeling -- trajectories -- viscous heat-conducting gas
Аннотация: The algorithm for numerical solving the Navier-Stokes equations for two-dimensional motion for viscous heat-conducting gas is proposed. The discretization of equations is performed by a combination of a special version of the trajectory method for a substantial derivative and the finite element method with piecewise bilinear basis functions for other terms. The results of numerical studies of the structure of a supersonic flow in a plane channel with an obstacle for a wide range of Mach numbers and Reynolds numbers are presented. Velocity and pressure fields are investigated, and the vortex structure of flow is studied in the circulation area of the obstacle. В© 2013 Springer-Verlag.
Scopus
Держатели документа:
Institute of Computational Modeling, Siberian Branch, Russian Academy of Science, Krasnoyarsk, Russian Federation
Beihang University, Beijing, China
Доп.точки доступа:
Shaydurov, V.V.; Shchepanovskaya, G.I.; Yakubovich, M.V.
Кл.слова (ненормированные):
finite element method -- Navier-Stokes equations -- numerical modeling -- trajectories -- viscous heat-conducting gas
Аннотация: The algorithm for numerical solving the Navier-Stokes equations for two-dimensional motion for viscous heat-conducting gas is proposed. The discretization of equations is performed by a combination of a special version of the trajectory method for a substantial derivative and the finite element method with piecewise bilinear basis functions for other terms. The results of numerical studies of the structure of a supersonic flow in a plane channel with an obstacle for a wide range of Mach numbers and Reynolds numbers are presented. Velocity and pressure fields are investigated, and the vortex structure of flow is studied in the circulation area of the obstacle. В© 2013 Springer-Verlag.
Scopus
Держатели документа:
Institute of Computational Modeling, Siberian Branch, Russian Academy of Science, Krasnoyarsk, Russian Federation
Beihang University, Beijing, China
Доп.точки доступа:
Shaydurov, V.V.; Shchepanovskaya, G.I.; Yakubovich, M.V.
XUV-Exposed, Non-Hydrostatic Hydrogen-Rich Upper Atmospheres of Terrestrial Planets. Part I: Atmospheric Expansion and Thermal Escape
[Text] / N. V. Erkaev [et al.] // Astrobiology. - 2013. - Vol. 13, Is. 11. - P1011-1029, DOI 10.1089/ast.2012.0957. - Cited References: 92. - M. Gudel, K. G. Kislyakova, M. L. Khodachenko, and H. Lammer acknowledge support by the FWF NFN project S116 601-N16 "Pathways to Habitability: From Disks to Active Stars, Planets and Life" and the related FWF NFN subprojects S116 604-N16 "Radiation & Wind Evolution from T Tauri Phase to ZAMS and Beyond," S116 606-N16 "Magnetospheric Electrodynamics of Exoplanets," S116 607-N16 "Particle/Radiative Interactions with Upper Atmospheres of Planetary Bodies under Extreme Stellar Conditions." K. G. Kislyakova, Yu. N. Kulikov, H. Lammer, and P. Odert thank also the Helmholtz Alliance project "Planetary Evolution and Life." P. Odert and A. Hanslmeier also acknowledge support from the FWF project P22950-N16. The authors also acknowledge support from the EU FP7 project IMPEx (No. 262863) and the EUROPLANET-RI projects, JRA3/EMDAF and the Na2 science WG5. The authors thank the International Space Science Institute (ISSI) in Bern and the ISSI team "Characterizing stellar and exoplanetary environments." N. V. Erkaev acknowledges support by the RFBR grant No 12-05-00152-a. Finally, the authors thank referee Tian Feng, from the Tsinghua University, Beijing, China, for suggestions and recommendations that helped to improve the work.
. - 19. - ISSN 1531-1074
РУБ Astronomy & Astrophysics + Biology + Geosciences, Multidisciplinary
Аннотация: The recently discovered low-density super-Earths Kepler-11b, Kepler-11f, Kepler-11d, Kepler-11e, and planets such as GJ 1214b represent the most likely known planets that are surrounded by dense H/He envelopes or contain deep H2O oceans also surrounded by dense hydrogen envelopes. Although these super-Earths are orbiting relatively close to their host stars, they have not lost their captured nebula-based hydrogen-rich or degassed volatile-rich steam protoatmospheres. Thus, it is interesting to estimate the maximum possible amount of atmospheric hydrogen loss from a terrestrial planet orbiting within the habitable zone of late main sequence host stars. For studying the thermosphere structure and escape, we apply a 1-D hydrodynamic upper atmosphere model that solves the equations of mass, momentum, and energy conservation for a planet with the mass and size of Earth and for a super-Earth with a size of 2 R-Earth and a mass of 10 M-Earth. We calculate volume heating rates by the stellar soft X-ray and extreme ultraviolet radiation (XUV) and expansion of the upper atmosphere, its temperature, density, and velocity structure and related thermal escape rates during the planet's lifetime. Moreover, we investigate under which conditions both planets enter the blow-off escape regime and may therefore experience loss rates that are close to the energy-limited escape. Finally, we discuss the results in the context of atmospheric evolution and implications for habitability of terrestrial planets in general. Key Words: Stellar activityLow-mass starsEarly atmospheresEarth-like exoplanetsEnergetic neutral atomsIon escapeHabitability. Astrobiology 13, 1011-1029.
WOS,
Scopus
Держатели документа:
[Erkaev, Nikolai V.] Russian Acad Sci, Siberian Div, Inst Computat Modelling, Krasnoyarsk 660036, Russia
[Erkaev, Nikolai V.] Siberian Fed Univ, Krasnoyarsk, Russia
[Lammer, Helmut
Odert, Petra
Kislyakova, Kristina G.
Khodachenko, Maxim L.
Biernat, Helfried] Austrian Acad Sci, Space Res Inst, A-8010 Graz, Austria
[Odert, Petra
Kislyakova, Kristina G.
Hanslmeier, Arnold] Graz Univ, Inst Phys, Graz, Austria
[Kulikov, Yuri N.] Russian Acad Sci, Polar Geophys Inst, Murmansk, Russia
[Khodachenko, Maxim L.] Moscow MV Lomonosov State Univ, Inst Nucl Phys, Moscow, Russia
[Guedel, Manuel] Univ Vienna, Inst Astrophys, A-1010 Vienna, Austria
ИВМ СО РАН
Доп.точки доступа:
Erkaev, N.V.; Еркаев, Николай Васильевич; Lammer, H.; Odert, P.; Kulikov, Y.N.; Kislyakova, K.G.; Khodachenko, M.L.; Gudel, M.; Hanslmeier, A.; Biernat, H.K.; FWF NFN project [S116 601-N16, S116 604-N16, S116 606-N16, S116 607-N16]; FWF project [P22950-N16]; EU [262863]; EUROPLANET-RI projects; JRA3/EMDAF; Na2 science WG5; RFBR [12-05-00152-a]
Рубрики:
HYDRODYNAMIC ESCAPE
GIANT PLANETS
HOT JUPITERS
MAGMA OCEAN
X-RAY
PRIMITIVE ATMOSPHERES
HABITABLE ZONE
CRITICAL MASS
EARLY EARTH
EVOLUTION
HYDRODYNAMIC ESCAPE
GIANT PLANETS
HOT JUPITERS
MAGMA OCEAN
X-RAY
PRIMITIVE ATMOSPHERES
HABITABLE ZONE
CRITICAL MASS
EARLY EARTH
EVOLUTION
Аннотация: The recently discovered low-density super-Earths Kepler-11b, Kepler-11f, Kepler-11d, Kepler-11e, and planets such as GJ 1214b represent the most likely known planets that are surrounded by dense H/He envelopes or contain deep H2O oceans also surrounded by dense hydrogen envelopes. Although these super-Earths are orbiting relatively close to their host stars, they have not lost their captured nebula-based hydrogen-rich or degassed volatile-rich steam protoatmospheres. Thus, it is interesting to estimate the maximum possible amount of atmospheric hydrogen loss from a terrestrial planet orbiting within the habitable zone of late main sequence host stars. For studying the thermosphere structure and escape, we apply a 1-D hydrodynamic upper atmosphere model that solves the equations of mass, momentum, and energy conservation for a planet with the mass and size of Earth and for a super-Earth with a size of 2 R-Earth and a mass of 10 M-Earth. We calculate volume heating rates by the stellar soft X-ray and extreme ultraviolet radiation (XUV) and expansion of the upper atmosphere, its temperature, density, and velocity structure and related thermal escape rates during the planet's lifetime. Moreover, we investigate under which conditions both planets enter the blow-off escape regime and may therefore experience loss rates that are close to the energy-limited escape. Finally, we discuss the results in the context of atmospheric evolution and implications for habitability of terrestrial planets in general. Key Words: Stellar activityLow-mass starsEarly atmospheresEarth-like exoplanetsEnergetic neutral atomsIon escapeHabitability. Astrobiology 13, 1011-1029.
WOS,
Scopus
Держатели документа:
[Erkaev, Nikolai V.] Russian Acad Sci, Siberian Div, Inst Computat Modelling, Krasnoyarsk 660036, Russia
[Erkaev, Nikolai V.] Siberian Fed Univ, Krasnoyarsk, Russia
[Lammer, Helmut
Odert, Petra
Kislyakova, Kristina G.
Khodachenko, Maxim L.
Biernat, Helfried] Austrian Acad Sci, Space Res Inst, A-8010 Graz, Austria
[Odert, Petra
Kislyakova, Kristina G.
Hanslmeier, Arnold] Graz Univ, Inst Phys, Graz, Austria
[Kulikov, Yuri N.] Russian Acad Sci, Polar Geophys Inst, Murmansk, Russia
[Khodachenko, Maxim L.] Moscow MV Lomonosov State Univ, Inst Nucl Phys, Moscow, Russia
[Guedel, Manuel] Univ Vienna, Inst Astrophys, A-1010 Vienna, Austria
ИВМ СО РАН
Доп.точки доступа:
Erkaev, N.V.; Еркаев, Николай Васильевич; Lammer, H.; Odert, P.; Kulikov, Y.N.; Kislyakova, K.G.; Khodachenko, M.L.; Gudel, M.; Hanslmeier, A.; Biernat, H.K.; FWF NFN project [S116 601-N16, S116 604-N16, S116 606-N16, S116 607-N16]; FWF project [P22950-N16]; EU [262863]; EUROPLANET-RI projects; JRA3/EMDAF; Na2 science WG5; RFBR [12-05-00152-a]
XUV-Exposed, Non-Hydrostatic Hydrogen-Rich Upper Atmospheres of Terrestrial Planets. Part II: Hydrogen coronae and ion escape
/ K. G. Kislyakova [et al.] // Astrobiology. - 2013. - Vol. 13, Is. 11. - P1030-1048, DOI 10.1089/ast.2012.0958
. - ISSN 1531-1074
Кл.слова (ненормированные):
Early atmospheres -- Earth-like exoplanets -- Energetic neutral atoms -- Habitability -- Ion escape -- Low-mass stars -- Stellar activity
Аннотация: We studied the interactions between the stellar wind plasma flow of a typical M star, such as GJ 436, and the hydrogen-rich upper atmosphere of an Earth-like planet and a "super-Earth" with a radius of 2 R Earth and a mass of 10 MEarth, located within the habitable zone at ∼0.24 AU. We investigated the formation of extended atomic hydrogen coronae under the influences of the stellar XUV flux (soft X-rays and EUV), stellar wind density and velocity, shape of a planetary obstacle (e.g., magnetosphere, ionopause), and the loss of planetary pickup ions on the evolution of hydrogen-dominated upper atmospheres. Stellar XUV fluxes that are 1, 10, 50, and 100 times higher compared to that of the present-day Sun were considered, and the formation of high-energy neutral hydrogen clouds around the planets due to the charge-exchange reaction under various stellar conditions was modeled. Charge-exchange between stellar wind protons with planetary hydrogen atoms, and photoionization, lead to the production of initially cold ions of planetary origin. We found that the ion production rates for the studied planets can vary over a wide range, from ∼1.0×1025 s-1 to ∼5.3×1030 s-1, depending on the stellar wind conditions and the assumed XUV exposure of the upper atmosphere. Our findings indicate that most likely the majority of these planetary ions are picked up by the stellar wind and lost from the planet. Finally, we estimated the long-time nonthermal ion pickup escape for the studied planets and compared them with the thermal escape. According to our estimates, nonthermal escape of picked-up ionized hydrogen atoms over a planet's lifetime within the habitable zone of an M dwarf varies between ∼0.4 Earth ocean equivalent amounts of hydrogen (EOH) to <3 EOH and usually is several times smaller in comparison to the thermal atmospheric escape rates. © 2013 Mary Ann Liebert, Inc.
Scopus
Держатели документа:
Space Research Institute, Austrian Academy of Sciences, Schmiedlstr. 6, A-8042 Graz, Austria
Institute of Physics, University of Graz, Graz, Austria
Swedish Institute of Space Physics, Kiruna, Sweden
Institute of Computational Modelling, Siberian Division of the Russian Academy of Sciences, Krasnoyarsk, Russian Federation
SINP, Moscow State University, Moscow, Russian Federation
Polar Geophysical Institute (PGI), Russian Academy of Sciences, Murmansk, Russian Federation
Institute of Astrophysics, University of Vienna, Austria
ИВМ СО РАН
Доп.точки доступа:
Kislyakova, K.G.; Lammer, H.; Holmstrom, M.; Panchenko, M.; Odert, P.; Erkaev, N.V.; Еркаев, Николай Васильевич; Leitzinger, M.; Khodachenko, M.L.; Kulikov, Y.N.; Gudel, M.; Hanslmeier, A.
Кл.слова (ненормированные):
Early atmospheres -- Earth-like exoplanets -- Energetic neutral atoms -- Habitability -- Ion escape -- Low-mass stars -- Stellar activity
Аннотация: We studied the interactions between the stellar wind plasma flow of a typical M star, such as GJ 436, and the hydrogen-rich upper atmosphere of an Earth-like planet and a "super-Earth" with a radius of 2 R Earth and a mass of 10 MEarth, located within the habitable zone at ∼0.24 AU. We investigated the formation of extended atomic hydrogen coronae under the influences of the stellar XUV flux (soft X-rays and EUV), stellar wind density and velocity, shape of a planetary obstacle (e.g., magnetosphere, ionopause), and the loss of planetary pickup ions on the evolution of hydrogen-dominated upper atmospheres. Stellar XUV fluxes that are 1, 10, 50, and 100 times higher compared to that of the present-day Sun were considered, and the formation of high-energy neutral hydrogen clouds around the planets due to the charge-exchange reaction under various stellar conditions was modeled. Charge-exchange between stellar wind protons with planetary hydrogen atoms, and photoionization, lead to the production of initially cold ions of planetary origin. We found that the ion production rates for the studied planets can vary over a wide range, from ∼1.0×1025 s-1 to ∼5.3×1030 s-1, depending on the stellar wind conditions and the assumed XUV exposure of the upper atmosphere. Our findings indicate that most likely the majority of these planetary ions are picked up by the stellar wind and lost from the planet. Finally, we estimated the long-time nonthermal ion pickup escape for the studied planets and compared them with the thermal escape. According to our estimates, nonthermal escape of picked-up ionized hydrogen atoms over a planet's lifetime within the habitable zone of an M dwarf varies between ∼0.4 Earth ocean equivalent amounts of hydrogen (EOH) to <3 EOH and usually is several times smaller in comparison to the thermal atmospheric escape rates. © 2013 Mary Ann Liebert, Inc.
Scopus
Держатели документа:
Space Research Institute, Austrian Academy of Sciences, Schmiedlstr. 6, A-8042 Graz, Austria
Institute of Physics, University of Graz, Graz, Austria
Swedish Institute of Space Physics, Kiruna, Sweden
Institute of Computational Modelling, Siberian Division of the Russian Academy of Sciences, Krasnoyarsk, Russian Federation
SINP, Moscow State University, Moscow, Russian Federation
Polar Geophysical Institute (PGI), Russian Academy of Sciences, Murmansk, Russian Federation
Institute of Astrophysics, University of Vienna, Austria
ИВМ СО РАН
Доп.точки доступа:
Kislyakova, K.G.; Lammer, H.; Holmstrom, M.; Panchenko, M.; Odert, P.; Erkaev, N.V.; Еркаев, Николай Васильевич; Leitzinger, M.; Khodachenko, M.L.; Kulikov, Y.N.; Gudel, M.; Hanslmeier, A.
Analysis of the Dispersion of Hydroacoustic Waves on the Basis of Viscoelastic Model
[Текст] : статья / V. M. Sadovskii, O. V. Sadovskaya, K. S. Svobodina // Journal of Siberian Federal University. Mathematics & Physics. - 2013. - Vol. 6, Iss. 3. - p. 342-348
Перевод заглавия: Анализ дисперсии гидроакустических волн на основе модели вязкоупругой среды
Кл.слова (ненормированные):
viscoelastic medium -- Poynting–Thomson model -- hydroacoustic wave -- dispersion -- grid-characteristic method
Аннотация: On the basis of mathematical model of the Poynting–Thomson viscoelastic medium the effect of acoustic dispersion of water is described: the phase velocity of waves of terahertz frequency is doubled in comparison with the velocity of waves of sound range. Rheological parameters of the model are selected by means of the values of the velocities of propagation of slow and fast monochromatic waves. The system of equations of the dynamics of the Poynting–Thomson viscoelastic medium is reduced to the form, hyperbolic by Friedrichs. It guarantees the correctness of the Cauchy problem and boundary value problems with dissipative boundary conditions, and also allows to use the monotone grid-characteristic schemes for numerical solution of problems. In the framework of 1D model the computations of a transformation of hydroacoustic waves, generated by U-shaped impulse of pressure, were performed. Results of computations show a strong damping of the fast precursor as it passes the distance of hundred nanometers from the moment of entry and the emergence of stable profile of the slow wave at the mesolevel.
Полный текст
Доп.точки доступа:
Sadovskaya, O.V.; Садовская, Оксана Викторовна; Svobodina, K.S.; Садовский, Владимир Михайлович
Перевод заглавия: Анализ дисперсии гидроакустических волн на основе модели вязкоупругой среды
Кл.слова (ненормированные):
viscoelastic medium -- Poynting–Thomson model -- hydroacoustic wave -- dispersion -- grid-characteristic method
Аннотация: On the basis of mathematical model of the Poynting–Thomson viscoelastic medium the effect of acoustic dispersion of water is described: the phase velocity of waves of terahertz frequency is doubled in comparison with the velocity of waves of sound range. Rheological parameters of the model are selected by means of the values of the velocities of propagation of slow and fast monochromatic waves. The system of equations of the dynamics of the Poynting–Thomson viscoelastic medium is reduced to the form, hyperbolic by Friedrichs. It guarantees the correctness of the Cauchy problem and boundary value problems with dissipative boundary conditions, and also allows to use the monotone grid-characteristic schemes for numerical solution of problems. In the framework of 1D model the computations of a transformation of hydroacoustic waves, generated by U-shaped impulse of pressure, were performed. Results of computations show a strong damping of the fast precursor as it passes the distance of hundred nanometers from the moment of entry and the emergence of stable profile of the slow wave at the mesolevel.
Полный текст
Доп.точки доступа:
Sadovskaya, O.V.; Садовская, Оксана Викторовна; Svobodina, K.S.; Садовский, Владимир Михайлович