A Study of High Latitude Current Systems During Quiet Geomagnetic Conditions Using Magsat Data

  1. Thomas A. Potemra
  1. J.R. Burrows,
  2. T.J. Hughes and
  3. Margaret D. Wilson

Published Online: 21 MAR 2013

DOI: 10.1029/GM028p0104

Magnetospheric Currents

Magnetospheric Currents

How to Cite

Burrows, J.R., Hughes, T.J. and Wilson, M. D. (1984) A Study of High Latitude Current Systems During Quiet Geomagnetic Conditions Using Magsat Data, in Magnetospheric Currents (ed T. A. Potemra), American Geophysical Union, Washington, D. C.. doi: 10.1029/GM028p0104

Author Information

  1. Herzberg Institute of Astrophysics, National Research Council of Canada, Ottawa, Canada K1A 0R6

Publication History

  1. Published Online: 21 MAR 2013
  2. Published Print: 1 JAN 1984

ISBN Information

Print ISBN: 9780875900551

Online ISBN: 9781118664131

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Keywords:

  • Magnetospheric currents—Congresses;
  • Plasma instabilities—Congresses

Summary

Magsat has provided precise vector measurements of the geomagnetic field which have confirmed the large scale Birkeland current pattern observed earlier by higher altitude satellites such as TRIAD and ISIS 2. In addition to detecting Birkeland currents, MAGSAT's lower orbit (≈300–500 km) permits measurement of both ionospheric currents and crustal magnetic anomalies. The large scale Region 1 and 2 Birkeland currents, which are the dominant feature in the dawn and dusk sectors during moderate magnetic activity, tend to be replaced, during quiet magnetic periods, by structured, small scale current sheets throughout the polar region and by correspondingly reduced ionospheric electrojets. Several Magsat orbits across the dark, winter polar cap are quantitatively modelled. Total electrojet current intensities ranging from 1.8×104 A to 1.9×105 A are inferred along with ratios of zonal to meridional current densities ranging from 0.8 to 1.7. The extension of these modelling procedures to more structured current systems during very quiet magnetic condition is considered and a method of achieving better separation of crustal anomaly fields from external fields is proposed.