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Record 3 of 9296
Simultaneous prenoon and postnoon observations of three field-aligned current systems from Viking and DMSP-F7
External Online Source: doi:10.1029/94JA02073
Author and Affiliation:
Ohtani, S.(Johns Hopkins Univ., Laurel, MD, United States)
Potemra, T. A.(Johns Hopkins Univ., Laurel, MD, United States)
Newell, P. T.(Johns Hopkins Univ., Laurel, MD, United States)
Zanetti, L. J.(Johns Hopkins Univ., Laurel, MD, United States)
Iijima, T.(Univ, of Tokyo, Tokyo, Japan)
Watanabe, M.(Univ, of Tokyo, Tokyo, Japan)
Yamauchi, M.(Swedish Institute of Space Physics, Kiruba, Sweden)
Elphinstone, R. D.(Univ. of Calgary, Calgary, Alberta, Canada)
De La Beauijardie, O.(SRI International, Menlo Park, CA, United States)
Blomberg, L. G.(Royal Insititute of Technology, Stockholm, Sweden)
Abstract: The spatial structure of dayside large-scale field-aligned current (FAC) systems is examined by using Viking and Defense Meteorological Satellite Program-F7 (DMSP-F7) data. We focus on four events in which the satellites simultaneously observed postnoon and prenoon three FAC systems: the region 2, the region 1, and the mantle (referred to as midday region O) systems, from equatorward to poleward. These events provide the most solid evidence to date that the midday region O system is a separate and unique FAC system, and is not an extension of the region 1 system from other local times. The events are examined comprehensively by making use of a mulit-instrumental data set, which includes magnetic field, particle flux, electric field, auroral UV image data from the satellites, and the Sondrestrom convection data. The results are summarized as follows: (1) Region 2 currents flow mostly in the central plasma sheet (CPS) precipitation region, often overlapping with the boundary plasma sheet (BPD) at their poleward edge. (2) The region 1 system is located in the core part of the auroral oval and is confined in a relatively narrow range in latitude which includes the convection reversal. The low-latitude boundary layer, possibly including the outer part of the plasma sheet, and the external cusp are the major source regions of dayside region 1 currents. (2) Midday region O currents flow on open field lines and are collocated with the shear of antisunward convection flows with velocites decreasing poleward. On the basis of these results we support the view that both prenoon and postnoon current systems consist of the three-sheet structure when the disctortion ofthe convection pattern associated with interplanetary magnetic field (IMF) B(sub Y) is small and both morningside and eveningside convection cells are crescent-shaped. We also propose that the midday region O and a part of the region 1 systems are closely coupled to the same source.
Publication Date: Jan 01, 1995
Document ID:
(Acquired Dec 28, 1995)
Accession Number: 95A85073
Subject Category: GEOPHYSICS
Document Type: Journal Article
Publication Information: Journal of Geophysical Research (ISSN 0148-0227); 100; A1; p. 119-136
Publisher Information: United States
Contract/Grant/Task Num: NSF ATM-91-02439
Financial Sponsor: NASA; United States
Organization Source: NASA; Washington, DC, United States
Description: 17p; In English
Distribution Limits: Unclassified; Publicly available; Unlimited
Rights: Copyright
Imprint And Other Notes: Journal of Geophysical Research vol. 100, no. A1 p. 119-136 January 1, 1995
Miscellaneous Notes: Research sponsored by NASA and Office of Naval Research
Availability Source: Other Sources
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