Premium
Field‐aligned current distributions generated by a divergent Hall current
Author(s) -
Buchert Stephan C.,
Budnik Frank
Publication year - 1997
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 - 10.1029/97gl00064
Subject(s) - magnetosphere , physics , current (fluid) , ionosphere , geophysics , field (mathematics) , current sheet , transient (computer programming) , current density , homogeneous , local time , latitude , computational physics , magnetic field , magnetohydrodynamics , astronomy , statistical physics , quantum mechanics , statistics , computer science , thermodynamics , operating system , mathematics , pure mathematics
In a horizontally homogeneous high‐latitude ionosphere a steady state Hall current closes within the E region and does not contribute to the interaction between the ionosphere and magnetosphere. When the steady state assumption is given up, Hall currents driven by a non‐zero ∂B/∂t become divergent and must transiently close via the magnetosphere. It is shown, that this process is of non‐local nature and can redistribute the field‐aligned current in space and time. At scales of tens of kilometers the effect becomes significant for frequencies at about 1 Hz and above, at larger scales even for lower frequencies. The rearrangement of the field‐aligned current is such that elongated structures tend to warp, and thus it resembles some of the typical dynamic evolution of auroral forms. Even a transient local amplification of the current density is possible.