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Control parameters for polar ionospheric convection patterns during northward interplanetary magnetic field
Author(s) -
Taguchi S.,
Hoffman R. A.
Publication year - 1996
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 - 10.1029/96gl00452
Subject(s) - convection , geophysics , interplanetary magnetic field , ionosphere , daytime , physics , convection cell , geology , magnetic field , solar wind , atmospheric sciences , mechanics , combined forced and natural convection , natural convection , quantum mechanics
Using the DE 2 electric field data from 191 dawndusk passes, we have sought parameters that distinguish between the various polar ionospheric convection patterns for northward IMF. The passes were divided into the daytime and nighttime sectors, and categorized the convection into three convection patterns for each sector by focusing on flow having a horizontal scale of >150 km. The three daytime sector patterns are convection of reverse polarity, i.e., sunward at the highest latitudes and antisunward on both sides of the sunward flow region, irregular convection having multiple sunward and antisunward flow regions, and convection having a single antisunward flow region at the highest latitude, which is similar to the pattern for southward IMF. The IMF clock (B Y /B Z ) angle, the Earth's dipole tilt angle, and the IMF B X /B Z angle measured from the dipole axis are the parameters that cause the difference in the three convection patterns. In the nighttime sector three similar convection patterns are identified. The occurrence of these patterns is controlled by the IMF clock angle. Thus, the convection pattern for northward IMF is very sensitive to the direction of the IMF. The magnetospheric sources for the convection patterns are discussed.