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Field‐aligned currents during IMF ∼0
Author(s) -
Papitashvili V. O.,
Christiansen F.,
Neubert T.
Publication year - 2001
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 - 10.1029/2001gl012944
Subject(s) - noon , interplanetary magnetic field , geophysics , magnetopause , geology , polar , solar wind , magnetosphere , physics , convection , magnetic field , field line , geodesy , atmospheric sciences , astronomy , meteorology , quantum mechanics
We report on field‐aligned currents (FAC) obtained from precise magnetic field measurements made on‐board the Ørsted and Magsat satellites when the interplanetary magnetic field (IMF) was near zero. We found that Region 1/Region 2 currents persist through southward IMF, IMF ∼ 0, and northward IMF; also the central area of both the northern and southern polar caps is always filled with FACs, even during slightly southward IMF. A statistical distribution of the latter currents resembles the dayside NBZ system with the downward/upward currents at post‐noon/pre‐noon hours, discovered earlier from Magsat observations. We hypothesize that the quasi‐viscous interaction of the solar wind with the magnetospheric lobes may cause a sunward convection of the lobes' field lines through the bunch's core, effectively mapping the FACs of NBZ‐type down to the near‐pole area.