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Formation of thin auroral arcs by current striation
Author(s) -
Otto A.,
Birk G. T.
Publication year - 1993
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 - 10.1029/93gl02492
Subject(s) - striation , electric field , current (fluid) , geophysics , ionosphere , plasma , field line , field (mathematics) , current sheet , shear (geology) , magnetic field , computation , physics , geology , computational physics , magnetohydrodynamics , computer science , paleontology , petrology , mathematics , algorithm , quantum mechanics , pure mathematics , thermodynamics
A model for the formation of auroral arcs is presented which provides an explanation for the extraordinary small thickness of auroral arcs and other morphological properties. The presence of field‐aligned current sheets allows for patchy (three‐dimensional) reconnection processes. Due to the presence of magnetic shear, the associated field‐aligned electric fields map to thin elongated regions at low altitudes. The ionospheric foot points of newly reconnected field lines can be interpreted as the locations of the auroral display. The process can occur in a cascading manner at varying altitudes depending on the local current densities and plasma conditions. The proposed properties are confirmed by results of three‐dimensional magnetohydrodynamik computations.