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On the two‐phase decay of the Dst‐variation
Author(s) -
Feldstein Y. I.,
Dremukhina L. A.,
Mall U.,
Woch J.
Publication year - 2000
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2000gl003783
Subject(s) - ring current , storm , context (archaeology) , physics , variation (astronomy) , current (fluid) , geomagnetic storm , phase (matter) , magnetosphere , computational physics , geophysics , magnetic field , geology , astrophysics , meteorology , solar wind , quantum mechanics , paleontology , thermodynamics
We discuss the well known observation that during the storm recovery phase the Dst ‐variation shows a two‐stage decay pattern, decaying first quickly and then decaying with a larger decay parameter. This finding is discussed in the context of the magnetic storm which was observed on November 25–27, 1986. Contrary to frequently used interpretations as two spatially separated ion populations or two different atomic ion components, we propose an alternative explanation for this feature. We argue that during the recovery phase of the magnetic storm the Dst decay is controlled by the decay of a two current system: the ring current (DR) and the magnetospheric tail current (DT).