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Kosch et al. 2000
Kosch, M.J., Amm, O. and Scourfield, M.W.J. (2000). A plasma vortex revisited: The importance of including ionospheric conductivity measurements. Journal of Geophysical Research 105: doi: 10.1029/2000JA900102. issn: 0148-0227.

In an earlier paper [Kosch et al., 1998>, simultaneous all-sky TV imager and Scandinavian Twin Auroral Radar Experiment (STARE) observations of an ionospheric plasma vortex located poleward of an auroral arc were presented. The vortex is associated with a sudden brightening of the arc and corresponds to an ionospheric region of diverging horizontal electric fields, which is equivalent to a downward field-aligned current (FAC), i.e., the closure current for the upward current above the arc. This event has been revisited because of the subsequent availability of data from the Scandinavian Magnetometer Array. These data, combined with STARE electric fields, have been used to determine the real ionospheric conductance distribution throughout the field of view. As a result, a more realistic, quantitative picture of the current system associated with the arc is obtained than was possible in an earlier model based on an assumed constant conductance. In particular, a complete macroscopic electrodynamic description of a plasma vortex, composed of ionospheric conductances, true horizontal currents, and FACs, is obtained for the first time. It is shown that the plasma vortex corresponds to an area of decreased conductance, thus broadening the FAC distribution and reducing the current density compared to the earlier results. The study illustrates that horizontal conductance gradients should not be neglected when computing FACs. ¿ 2000 American Geophysical Union

BACKGROUND DATA FILES

Abstract

Keywords
Ionosphere, Auroral ionosphere, Ionosphere, Current systems, Ionosphere, Electric fields
Journal
Journal of Geophysical Research
http://www.agu.org/journals/jb/
Publisher
American Geophysical Union
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