Open AccessAuroral forms and the field‐aligned current structure associated with field line resonances
Author(s) -
Milan Stephen E.,
Sato Natsuo,
Ejiri Masaki,
Moen Jøran
Publication year - 2001
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2001ja900077
Subject(s) - field line , current (fluid) , field (mathematics) , geophysics , physics , magnetohydrodynamic drive , line (geometry) , alfvén wave , resonance (particle physics) , harmonic , latitude , computational physics , geology , magnetohydrodynamics , magnetic field , geometry , astronomy , atomic physics , acoustics , mathematics , quantum mechanics , pure mathematics , thermodynamics
We show evidence to suggest that some auroral forms may be related to the field‐aligned current structure associated with magnetohydrodynamic wave activity, specifically field line resonances. These auroras appear as a series of azimuthally spaced east‐west elongated arcs, inclined slightly from north to south. Modeling shows that this “braided” appearance reflects the locations of upward field‐aligned current driven by the wave. Moreover, more complicated auroral structures can be produced if several harmonically related waves occur together. We model a situation in which two harmonic components are present at the latitude of resonance and demonstrate the striking similarity between the resulting field‐aligned current structures and actual auroral observations.