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The Distant Tail at 200 R(sub E): Comparison Between Geotail Observations and the Results from a Global Magnetohydrodynamic SimulationThis paper reports a comparison between Geotail observations of plasmas and magnetic fields at 200 R(sub E) in the Earth's magnetotail with results from a time-dependent, global magnetohydrodynamic simulation of the interaction of the solar wind with the magnetosphere. The study focuses on observations from July 7, 1993, during which the Geotail spacecraft crossed the distant tail magnetospheric boundary several times while the interplanetary magnetic field (IMF) was predominantly northward and was marked by slow rotations of its clock angle. Simultaneous IMP 8 observations of solar wind ions and the IMF were used as driving input for the MHD simulation, and the resulting time series were compared directly with those from the Geotail spacecraft. The very good agreement found provided the basis for an investigation of the response of the distant tail associated with the clock angle of the IMF. Results from the simulation show that the stresses imposed by the draping of magnetosheath field lines and the asymmetric removal of magnetic flux tailward of the cusps altered considerably the shape of the distant tail as the solar wind discontinuities convected downstream of Earth. As a result, the cross section of the distant tail was considerably flattened along the direction perpendicular to the IMF clock angle, the direction of the neutral sheet following that of the IMF. The simulation also revealed that the combined action of magnetic reconnection and the slow rotation of the IMF clock angle led to a braiding of the distant tail's magnetic field lines along the axis of the tail, with the plane of the braid lying in the direction of the IMF.
Document ID
19990027438
Acquisition Source
Goddard Space Flight Center
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Berchem, J.
(California Univ. Los Angeles, CA United States)
Raeder, J.
(California Univ. Los Angeles, CA United States)
Ashour-Abdalla, M.
(California Univ. Los Angeles, CA United States)
Frank, L. A.
(Iowa Univ. Iowa City, IA United States)
Paterson, W. R.
(Iowa Univ. Iowa City, IA United States)
Ackerson, K. L.
(Iowa Univ. Iowa City, IA United States)
Kokubun, S.
(Nagoya Univ. Toyokawa, Japan)
Yamamoto, T.
(Tokyo Univ. Sagamihara, Japan)
Lepping, R. P.
(NASA Goddard Space Flight Center Greenbelt, MD United States)
Date Acquired
August 19, 2013
Publication Date
May 1, 1998
Publication Information
Publication: Journal of Geophysical Research
Publisher: American Geophysical Union
Volume: 103
Issue: A5
ISSN: 0148-0227
Subject Category
Geophysics
Report/Patent Number
IGPP Publ-4876
Paper-97JA02926
Funding Number(s)
CONTRACT_GRANT: NAGw-1100
CONTRACT_GRANT: NAGw-4541
CONTRACT_GRANT: NAGw-4543
CONTRACT_GRANT: NAG5-2371
Distribution Limits
Public
Copyright
Other

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