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Title: On the influence of localized electric fields and field-aligned currents associated with polar arcs on the global potential distribution

Abstract

The influence of localized field-aligned current, associated with intense transpolar arcs mostly occurring during periods of northward interplaentary magnetic field (IMF), on the global electrodynamics has been investigated using a numerical simulation model. Idealized field-aligned current distributions representing both the region 1/2 system of the auroral oval and the transpolar arc as well as a corresponding ionospheric conductivity distribution are fed into the model to calculate the potential distributions. The transpolar arc has been represented by a few alternative field-aligned current distributions which are different in the way the downward return currents are distributed in the ionosphere. If the conductivity of the main auroral oval is comparable to that of the polar arc the dusk cell will have two local potential minima and thus a region of weak antisunward convection in between. Depending on the direction of the polar arc current sheets the dawn-dusk electric field will either be reversed (or weakened) or intensified at the location of the transpolar arc. The presence of a reversal depend, however, not only on the relative magnitude between the polar arc current sand those of the region 1/2 system but also on the characteristics of the acceleration region and of the conductivity distributionmore » associated with the polar arc. Comparisons are made between the model results and Viking electric field data for a number of polar arc crossings to reveal the most common electrodynamical signatures of these auroral phenomena.« less

Authors:
;  [1]
  1. (Royal Inst. of Tech., Stockholm (Sweden))
Publication Date:
OSTI Identifier:
5255923
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Geophysical Research; (United States); Journal Volume: 96:A8
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; POLAR-CAP AURORAE; ELECTRODYNAMICS; AURORAL OVAL; ELECTRIC CONDUCTIVITY; ELECTRIC CURRENTS; INTERACTIONS; INTERPLANETARY MAGNETIC FIELDS; MAGNETIC BAYS; MATHEMATICAL MODELS; MORPHOLOGY; SOLAR WIND; AURORAE; CURRENTS; ELECTRICAL PROPERTIES; MAGNETIC FIELDS; PHYSICAL PROPERTIES; SOLAR ACTIVITY; 640201* - Atmospheric Physics- Auroral, Ionospheric, & Magetospheric Phenomena

Citation Formats

Marklund, G.T., and Blomberg, L.G.. On the influence of localized electric fields and field-aligned currents associated with polar arcs on the global potential distribution. United States: N. p., 1991. Web. doi:10.1029/91JA01120.
Marklund, G.T., & Blomberg, L.G.. On the influence of localized electric fields and field-aligned currents associated with polar arcs on the global potential distribution. United States. doi:10.1029/91JA01120.
Marklund, G.T., and Blomberg, L.G.. Thu . "On the influence of localized electric fields and field-aligned currents associated with polar arcs on the global potential distribution". United States. doi:10.1029/91JA01120.
@article{osti_5255923,
title = {On the influence of localized electric fields and field-aligned currents associated with polar arcs on the global potential distribution},
author = {Marklund, G.T. and Blomberg, L.G.},
abstractNote = {The influence of localized field-aligned current, associated with intense transpolar arcs mostly occurring during periods of northward interplaentary magnetic field (IMF), on the global electrodynamics has been investigated using a numerical simulation model. Idealized field-aligned current distributions representing both the region 1/2 system of the auroral oval and the transpolar arc as well as a corresponding ionospheric conductivity distribution are fed into the model to calculate the potential distributions. The transpolar arc has been represented by a few alternative field-aligned current distributions which are different in the way the downward return currents are distributed in the ionosphere. If the conductivity of the main auroral oval is comparable to that of the polar arc the dusk cell will have two local potential minima and thus a region of weak antisunward convection in between. Depending on the direction of the polar arc current sheets the dawn-dusk electric field will either be reversed (or weakened) or intensified at the location of the transpolar arc. The presence of a reversal depend, however, not only on the relative magnitude between the polar arc current sand those of the region 1/2 system but also on the characteristics of the acceleration region and of the conductivity distribution associated with the polar arc. Comparisons are made between the model results and Viking electric field data for a number of polar arc crossings to reveal the most common electrodynamical signatures of these auroral phenomena.},
doi = {10.1029/91JA01120},
journal = {Journal of Geophysical Research; (United States)},
number = ,
volume = 96:A8,
place = {United States},
year = {Thu Aug 01 00:00:00 EDT 1991},
month = {Thu Aug 01 00:00:00 EDT 1991}
}