Results 131 to 140 of about 232 (164)

Primary sources of large-scale Birkeland currents

Space Science Reviews, 1979
We review generation mechanisms of Birkeland currents (field-aligned currents) in the magnetosphere and the ionosphere. Comparing Birkeland currents predicted theoretically with those studied observationally by spacecraft experiments, we present a model for driving mechanism, which is unified by the solar wind-magnetosphere interaction that allows the ...
Tetsuya Sato, Takesi Iijima
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Ionospheric closure of small‐scale Birkeland Currents

Journal of Geophysical Research: Space Physics, 1991
In this paper, we study the relationship between the spatial variations of the perpendicular electric field observed in the topside ionosphere and those of the magnetic field induced by the associated field‐aligned currents. The mapping of the magnetospheric electric field down to the ionosphere depends upon the spatial scale of its variations and ...
B. Forget, J.‐C. Cerisier, A. Berthelier, J.‐J. Berthelier   +3 more
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Field line mapping and Birkeland currents

2000
We describe the preliminary development of an open magnetosphere model that includes the magnetic effects of Birkeland (magnetic-field-aligned) currents in a self-consistent way. This model is designed to satisfy two criteria: (1) when mapped to the ionosphere, the Birkeland current should be consistent with that computed by taking the divergence of ...
F. R. Toffoletto, T. W. Hill
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Large-Scale Characteristics of Birkeland Currents

1979
During his polar expeditions of 1902–1903, Kristian Birkeland determined that large-scale ionospheric currents were associated with the aurora. Birkeland suggested that these currents originated far from the earth and that they flowed into and away from the polar atmosphere along the geomagnetic field lines.
T. A. Potemra, T. Iijima, N. A. Saflekos
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Birkeland Currents in Cosmic Plasma

1992
An electromotive force ϕ = ∫ v × B⋅ dl giving rise to electrical currents in conducting media is produced wherever a relative perpendicular motion of plasma and magnetic field lines exist (Sect. 3.5.2). An example of this is the sunward convective motion of the magnetospheric plasma that cuts the earth’s dipole field lines through the equatorial plane,
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Large‐scale Birkeland currents in the dayside polar region during strongly northward IMF: A new Birkeland current system

Journal of Geophysical Research: Space Physics, 1984
Stable, well‐defined patterns of transverse magnetic disturbances have been observed in the polar regions that persist during periods of strongly positive Bz (≥ 5 nT) and that increase in amplitude as Bz increases. This has been determined from an examination of magnetic field data acquired during 146 orbits of MAGSAT over the south polar regions ...
T. Iijima, T. A. Potemra, L. J. Zanetti, P. F. Bythrow   +3 more
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Rotationally-induced Birkeland current systems

1984
Rotational effects which are negligible in earth's magnetosphere become dominant in the magnetospheres of the outer planets where they give rise to Birkeland current circuits coupling the ionospheric and magnetospheric motions. The centrifugal force of corotation produces an azimuthal ring current in the magnetosphere while the Coriolis force produces ...
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Relationships between the Birkeland currents, ionospheric currents, and electric fields

Journal of Geophysical Research: Space Physics, 1982
Calculations are made of the currents and electric fields in the ionosphere by using a global model of the electron densities including conjugate coupling along field lines. Incoherent scatter and rocket measurements of high‐latitude electron densities have been used to derive realistic variations of the polar conductivities as a function of magnetic ...
E. Bleuler, C. H. Li, J. S. Nisbet
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The morphology of dayside Birkeland currents

Journal of Atmospheric and Terrestrial Physics, 1992
Abstract Intense (10 5 A) electric currents flow into and from the Earth's two polar ionospheres near magnetic noon. These currents, called Birkeland or magnetic field-aligned currents, are the agent by which momentum couples from the flowing solar wind plasma to drive plasma motions in the high latitude ionosphere.
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Electric field mapping and auroral Birkeland currents

Journal of Geophysical Research: Space Physics, 1989
Magnetic field lines, electric fields and equipotentials have been mapped throughout the magnetosphere in the vicinity of strong Birkeland currents. It was found that a uniform electric field at either the ionospheric or the equatorial end of a field line can map to a highly structured field at the other end if strong Birkeland currents are located ...
Richard L. Kaufmann, Douglas J. Larson
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