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Найдено документов в текущей БД: 4

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

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


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

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

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


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

    Plasma depletion layer model for low Alfven Mach number: Comparison with ISEE observations
[Text] / C. J. Farrugia [et al.] // J. Geophys. Res-Space Phys. - 1997. - Vol. 102, Is. A6. - P11315-11324DOI 10.1029/97JA00410. - Cited References: 29 . -
РУБ Astronomy & Astrophysics

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


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

    Diagrams of the state of a steady-state arc discharge in hydrogen and helium
[Text] / E. N. Vasil'ev // Tech. Phys. - 2014. - Vol. 59, Is. 12. - P1775-1779, DOI 10.1134/S1063784214120287. - Cited References: 12 . - ISSN 1063-7842. - ISSN 1090-6525
РУБ Physics, Applied

Аннотация: The temperature, electric field strength, and specific and integrated powers of energy mechanisms of an axisymmetric steady-state equilibrium arc discharge in hydrogen and helium under atmospheric pressure are calculated for various values of the current and radius. The results of calculations are presented in the form of state diagrams intended for estimating the main energy characteristics of electric arcs.

WOS

Держатели документа:
Russian Acad Sci, Inst Computat Modeling, Siberian Branch, Krasnoyarsk 660036, Russia
ИВМ СО РАН

Доп.точки доступа:
Vasil'ev, E.N.; Васильев, Евгений Николаевич