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Satellite observations of currents and waves in space plasmas†

Published online by Cambridge University Press:  09 March 2009

T. A. Potemra ,
M. J. Engebretson ,
L. J. Zanetti ,
R. E. Erlandson  and
P. F. Bythrow
T. A. Potemra
Affiliation:
The Johns Hopkins University, Applied Physics Laboratory, Laurel, MD 20707
M. J. Engebretson
Affiliation:
Augsburg College, Minneapolis, MN 55454
L. J. Zanetti
Affiliation:
The Johns Hopkins University, Applied Physics Laboratory, Laurel, MD 20707
R. E. Erlandson
Affiliation:
The Johns Hopkins University, Applied Physics Laboratory, Laurel, MD 20707
P. F. Bythrow
Affiliation:
The Johns Hopkins University, Applied Physics Laboratory, Laurel, MD 20707
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Abstract

When viewed from outer space, the earth's magnetic field does not resemble a simple dipole, but is severely distorted into a comet-shaped configuration by the continuous flow of solar wind plasma. A complicated system of currents flows within this distorted magnetic field configuration called the ‘magnetosphere’ (See figure 1). For example, the compression of the geomagnetic field by the solar wind on the dayside of the earth is associated with a large-scale current flowing across the geomagnetic field lines, called the ‘Chapman-Ferraro’ or magnetopause current. The magnetospheric system includes large-scale currents that flow in the ‘tail’, the ring current that flows at high altitudes around the equator of the earth, field-aligned ‘Birkeland’ currents that flow along geomagnetic field lines into and away from the two auroral regions, and a complex system of currents that flows completely within the layers of the ionosphere, the earth's ionized atmosphere. The intensities of these various currents reach millions of amperes and are closely related to solar activity. The geomagnetic field lines can also oscillate, like giant vibrating strings, at specified resonant frequencies. The effects of these vibrations, sometimes described as ‘standing Alfvén waves’, have been observed on the ground in magnetic field recordings dating back to the beginning of the century. Observations of currents and waves with satellite-borne magnetic field experiments have provided a new perspective on the complicated plasma processes that occur in the magnetosphere. Some of the new observations are described here.

Type
Research Article
Information
Laser and Particle Beams , Volume 6 , Issue 3 , August 1988 , pp. 503 - 511
Copyright
Copyright © Cambridge University Press 1988

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References

Alfvén, H. 1939 Proceedings of the Royal Swedish Academy of Sciences 18, 3.Google Scholar
Birkeland, K. 1908. The Norwegian Aurora Polaris Expedition 1902–3, Vol. 1, On the Cause of Magnetic Storms and the Origin of Terrestrial Magnetism, H. Ascheboug & Co., Christiana (Oslo).Google Scholar
Chapman, S. 1927 Proceedings of the Royal Society A115, 242.Google Scholar
Chen, L. & Hasegawa, A. 1974 J. Geophys. Res. 79, 1024.CrossRefGoogle Scholar
Cummings, W. D. & Dessler, A. J. 1967 J. Geophys. Res. 72, 1007.CrossRefGoogle Scholar
Cummings, W. D., O'Sullivan, R. J. & Coleman, P. J. Jr., 1969 J. Geophys. Res. 74, 778.CrossRefGoogle Scholar
Engebreston, M. J. et al. 1986 Geophys. Res. Lett. 13, 905.CrossRefGoogle Scholar
Engebretson, M. J. et al. 1987 J. Geophys. Res. 92, 10,053.Google Scholar
Egeland, A. 1984 in Magnetospheric Currents, Potemra, T. A. (ed.), Am. Geophys. Union, Washington, D.C., pp. 1–16.Google Scholar
Fukushima, N. 1969 Rep. Ionos. Space Res. Jap 23, 219.Google Scholar
Haerendel, G. et al. 1986 Nature 320, 720.CrossRefGoogle Scholar
Hultovist, B. 1987 Geophys. Res. Lett. 14, 379.CrossRefGoogle Scholar
Iijima, T. & Potemra, T. A. 1976 J. Geophys. Res. 8, 5971.CrossRefGoogle Scholar
Lundin, R. et al. 1987 Geophys. Res. Lett. 14, 443.CrossRefGoogle Scholar
Mauk, B. H. & Zanetti, L. J. 1987 Revs. Geophys. 25, 541.CrossRefGoogle Scholar
Potemra, T. A. (editor) 1984 Magnetospheric Currents, published by Am. Geophys. Union, Washington, D.C.CrossRefGoogle Scholar
Potemra, T. A. et al. 1987 Geophys. Res. Lett. 14, 419.CrossRefGoogle Scholar
Potemra, T. A. et al. 1988 J. Geophys. Res. 93, 2661.CrossRefGoogle Scholar
Radoski, H. R. 1974 J. Geophys. Res. 79, 595.CrossRefGoogle Scholar
Saflekos, N. A.Sheehan, R. E. & Carovillano, R. L. 1982 Rev. Geophys. Space Phys. 20, 709.CrossRefGoogle Scholar
Southwood, D. J. 1974 Planet. Space Sci. 22, 483.CrossRefGoogle Scholar
Sugiura, M. & Wilson, C. R. 1964 J. Geophys. Res. 69, 1211.CrossRefGoogle Scholar
The Viking Science Team 1986 EOS Trans. Am. Geophys. Union 67, 793.CrossRefGoogle Scholar
Zanetti, L. J. et al. 1987 Geophys. Res. Lett. 14, 427.CrossRefGoogle Scholar
Zmuda, A. J., Martin, J. H. & Huering, F. T. 1966 J. Geophys. Res. 71, 5033.CrossRefGoogle Scholar
Zmuda, A. J., Heuring, F. T. & Martin, J. H. 1967, J. Geophys. Res. 72, 1115.CrossRefGoogle Scholar