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Polar cap arcs and the plasma sheet
Author(s) -
Meng ChingI.
Publication year - 1981
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/gl008i003p00273
Subject(s) - polar , magnetosphere , plasma sheet , earth's magnetic field , electron precipitation , solar wind , geophysics , polar cap , latitude , geology , geomagnetic latitude , ionosphere , high latitude , atmospheric sciences , quiet , physics , plasma , geodesy , astronomy , magnetic field , quantum mechanics
This letter suggests that most of the so‐called ‘polar cap arcs’ with the sun‐aligned orientation at the high geomagnetic latitude region occurring during the quiescent magnetosphere are actually a part of discrete arcs in the auroral oval as a consequence of the poleward widening of the quiet auroral oval. This suggestion is based on (1) a detailed examination of two months of DMSP electron precipitation data and simultaneous auroral observations, (2) the observed widening in the latitudinal extent of the auroral oval precipitation to the very high geomagnetic latitude (≳80°) and the simultaneous occurrence of the sun‐aligned arcs, and (3) the conjugate widening of the quiet auroral oval over both the northern and southern polar regions. The new interpretation of the ‘polar cap arcs’ is discussed in terms of the present understanding of the solar wind‐magnetospheric interaction.