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Relationship between four‐cell and distorted two‐cell convection patterns during northward IMF
Author(s) -
Zhu L.,
Kan J. R.
Publication year - 1990
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/gl017i013p02325
Subject(s) - interplanetary magnetic field , geophysics , convection , solar wind , magnetosphere , ionosphere , physics , geology , interplanetary spaceflight , magnetic field , mechanics , quantum mechanics
Four‐cell convection pattern in the ionosphere during a northward IMF (interplanetary magnetic field) was widely accepted until it was challenged by the distorted two‐cell convection pattern proposed by Heppner and Maynard [1987]. We propose that a four‐cell convection pattern, imposed on the magnetosphere by the solar wind, can be distorted into a wrapped two‐cell pattern by the nonuniform and anisotropic conductance in the ionosphere. This is demonstrated by extending the magnetosphere‐ionosphere coupling model [Kan et al., 1988] to the northward IMF condition. The resulting wrapped two‐cell patterns for positive and negative IMF B y are similar to the empirical two‐cell patterns obtained by Heppner and Maynard [1987]. The distributions of the resulting field‐aligned currents are also characteristically consistent with the observed current distributions, including the NBZ currents, during northward IMF.