Near-Earth substorm features from multiple satellite observations

Lui, A. T. Y. and Volwerk, M. and Dunlop, M. W. and Alexeev, I. V. and Fazakerley, A. N. and Walsh, A. P. and Lester, M. and Grocott, A. and Mouikis, C. and Henderson, M. G. and Kistler, L. M. and Shen, C. and Shi, J. K. and Zhang, T. L. and Rème, H. (2008) Near-Earth substorm features from multiple satellite observations. Journal of Geophysical Research, 113 (A7). ISSN 0148-0227

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We investigate a substorm on 3 October 2004 during which 11 satellites were located in near-Earth magnetotail (XGSM > −10 RE). Double Star 1 (TC-1), Cluster, and LANL-97 satellites were closely aligned in the dawn-dusk direction (<1 RE apart) for this conjunction. After substorm expansion onset, TC-1 observed plasma sheet thinning at X ≈ −5.5 RE and later detected signature of plasma flow shear that may be associated with an auroral arc. Analysis of the dawn-dusk magnetic perturbations from GOES-10 and Polar suggests that these could be caused by a substorm current system consisting of not only the azimuthal closure of field-aligned currents (the substorm current wedge) but also the meridional closure of field-aligned currents. The temporal sequence of substorm activity (particle injection, current disruption, and dipolarization) revealed by these satellites indicates that the substorm expansion activity was initiated close to the Earth and spread later to further downstream distances. Furthermore, TC-1 and Cluster data show that there is no close relationship between some dipolarizations and Earthward plasma flows in the near-Earth region. The overall development of substorm activity is in agreement with the near-Earth initiation model for substorms. A temporal evolution of the magnetic field reconfiguration and plasma boundary motion during this substorm is constructed from these observations.

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Journal Article
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Journal of Geophysical Research
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Copyright 2008 by the American Geophysical Union.
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11 Oct 2013 12:39
Last Modified:
22 Nov 2022 00:20