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Space current around the earth obtained with Ampère’s law applied to the MAGSAT orbit and data

Abstract

An application of Ampère’s law to the MAGSAT orbit and data enabled us to study the net space current (total intensity I) flowing through the plane enclosed by the satellite orbit, and its dependence on the ground magnetic disturbance revealed in the Kp- or AE-index. Even on magnetically quiet days, MAGSAT often (or sometimes persistently) detected minor or moderate disturbances in the polar regions, in particular inside the auroral oval, without increasing Kp- or AE-values. Such disturbances are attributable to field-aligned currents into or out of the ionosphere, which produce a magnetic field (of toroidal nature) detectable above the ionosphere associated with a weak magnetic field on the ground, resulting in an occasional poor correlation of I with Kp- or AE-indices. The calculated I-values on quiet days are shown to be the order of 105 A, with a small-range UT variation. During magnetic storms or substorms the I-values become one order of magnitude greater, and the net space current is always antisunward, with its intensity roughly proportional to the AE-index values. The antisunward space current under the MAGSAT level is the Pedersen current in the ionosphere, and it constitutes the return current of the westward partial ring current (flowing at a distance of several earth radii in the dusk-side magnetosphere) along with the field-aligned currents between the partial ring current and the high-latitude ionosphere in the dayside and nightside hemispheres. The antisunward ionospheric current under the MAGSAT level contributes to a noticeable enhancement in the dawn-dusk asymmetry of the H-decrease at MAGSAT level in comparison with the ground data at the developing stage of magnetic storms or substorms.

References

  1. Barfield, J. N., N. A. Saflekos, R. E. Sheehan, R. L. Carovillano, T. A. Potemra, and D. Knecht, Three-dimensional observations of Birkeland currents, J. Geophys. Res., 91, 4393–4403, 1986.

    Article  Google Scholar 

  2. Bythrow, P. F. and T. A. Potemra, The relationship of total Birkeland currents to the merging electric field, Geophys. Res. Lett., 10, 573–576, 1983.

    Article  Google Scholar 

  3. Crooker, N. U. and R. L. McPherron, On the distinction between the auroral electrojet and partial ring current systems, J. Geophys. Res., 77, 6886–6889, 1972.

    Article  Google Scholar 

  4. Crooker, N. U. and G. L. Siscoe, A study of the geomagnetic disturbance field asymmetry, Radio Sci., 6, 495–501, 1971.

    Article  Google Scholar 

  5. Crooker, N. U. and G. L. Siscoe, Birkeland currents as the cause of the low-latitude asymmetric disturbance field, J. Geophys. Res., 86, 11,201–11,210, 1981.

    Article  Google Scholar 

  6. Cummings, W. D., Asymmetric ring currents and the low-latitude distur-bance daily variation, J. Geophys. Res., 71, 4495–4503, 1966.

    Article  Google Scholar 

  7. Engebretson, M. J., L. J. Cahill, Jr., T. A. Potemra, L. J. Zanetti, R. L. Arnoldy, S. B. Mende, and T. J. Rosenberg, On the relationship between morning sector irregular magnetic pulsations and field aligned currents, J. Geophys. Res., 89, 1602–1612, 1984.

    Article  Google Scholar 

  8. Fujii, R. and T. Iijima, Control of the ionospheric conductivities on large-scale Birkeland current intensities under geomagnetic quiet condi-tions, J. Geophys. Res., 92, 4505–4513, 1987.

    Article  Google Scholar 

  9. Fukushima, N., Generalized theorem for no ground magnetic effect of vertical currents connected with Pedersen currents in the uniform-conductivity ionosphere, Rep. Ionos. Space Res. Japan, 30, 35–40, 1976.

    Google Scholar 

  10. Fukushima, N. and Y. Kamide, Partial ring current models for worldwide geomagnetic disturbances, Rev. Geophys. Space Phys., 11, 795–853, 1973.

    Article  Google Scholar 

  11. Hughes, T. J., D. D. Wallis, J. R. Burrows, and M. D. Wilson, Model predictions of magnetic perturbations observed by MAGSAT in dawn-dusk orbit, Geophys. Res. Lett., 9, 357–360, 1982.

    Google Scholar 

  12. Iijima, T. and T. A. Potemra, Large-scale characteristics of field-aligned currents associated with substorms, J. Geophys. Res., 83, 599–615, 1978.

    Article  Google Scholar 

  13. Iijima, T. and T. Shibaji, Global characteristics of northward IMF-associated (NBZ) field-aligned currents, J. Geophys. Res., 92, 2408–2424, 1987.

    Article  Google Scholar 

  14. Iijima, T., N. Fukushima, and R. Fujii, Transverse and parallel geomag-netic perturbations over the polar regions observed by MAGSAT, Geophys. Res. Lett., 9, 369–372, 1982.

    Article  Google Scholar 

  15. Iijima, T., T. A. Potemra, L. J. Zanetti, and P. F. Bythrow, Large-scale Birkeland currents in the dayside polar region during strongly north-ward IMF: A new Birkeland current system, J. Geophys. Res., 89, 7441–7452, 1984.

    Article  Google Scholar 

  16. Iyemori, T., Storm-time magnetospheric currents inferred from mid-latitude geomagnetic field variations, J. Geomag. Geoelectr., 42, 1249–1265, 1990.

    Article  Google Scholar 

  17. Iyemori, T. and D. R. K. Rao, Decay of the Dst field of geomagnetic disturbance after substorm onset and its implication to storm-substorm relation, Ann. Geophys., 14, 608–618, 1996.

    Article  Google Scholar 

  18. Iyemori, T., T. Ikeda, and A. Nakagawa, Amplitude distribution of small-scale magnetic fluctuations over the polar ionosphere observed by Magsat, J. Geophys. Res., 90, 12,335–12,339, 1985.

    Article  Google Scholar 

  19. Kamide, Y. and N. Fukushima, Positive geomagnetic bays in evening high-latitudes and their possible connection with partial ring current, Rept. Ionos. Space Res. Japan, 26, 79–101, 1972.

    Google Scholar 

  20. Kamide, Y., D. S. Evans, and J. C. Cain, A comparison of field-aligned current signatures simultaneously observed by the MAGSAT and TIROS/NOAA spacecraft, J. Geomag. Geoelectr., 36, 521–527, 1984.

    Article  Google Scholar 

  21. Kan, J. R., T. Iijima, and S.-I. Akasofu, A model of coupled radial and azimuthal current loops associated with substorms, J. Geophys. Res., 95, 21,291–21,295, 1990.

    Article  Google Scholar 

  22. Klumpar, D. M. and D. M. Greer, A technique for modeling the magnetic perturbations produced by field-aligned current systems, Geophys. Res. Lett., 9, 361–364, 1982.

    Article  Google Scholar 

  23. Lanchester, B. S. and D. D. Wallis, Magnetic field disturbances over auroral arcs observed from Spitsbergen, J. Geophys. Res., 90, 2473–2480, 1985.

    Article  Google Scholar 

  24. Langel, R. A., The magnetic earth as seen from MAGSAT, initial results, Geophys. Res. Lett., 9, 239–242, 1982.

    Article  Google Scholar 

  25. Langel, R. A., G. Ousley, J. Berbert, J. Murphy, and M. Settle, The MAGSAT mission, Geophys. Res. Lett., 9, 243–245, 1982.

    Article  Google Scholar 

  26. Maeda, H., T. Iyemori, T. Araki, and T. Kamei, New evidence of a meridional current system in the equatorial ionosphere, Geophys. Res. Lett., 9, 337–340, 1982.

    Article  Google Scholar 

  27. Maeda, H., T. Kamei, T. Iyemori, and T. Araki, Geomagnetic perturba-tions at low latitudes observed by Magsat, J. Geophys. Res., 90, 2481–2486, 1985.

    Article  Google Scholar 

  28. Potemra, T. A., L. J. Zanetti, P. F. Bythrow, A. T. Y. Lui, and T. Iijima, By-dependent convection patterns during northward interplanetary magnetic field, J. Geophys. Res., 89, 9753–9760, 1984.

    Article  Google Scholar 

  29. Suzuki, A. and N. Fukushima, Sunward or anti-sunward electric current in space below the MAGSAT level, Geophys. Res. Lett., 9, 345–347, 1982.

    Article  Google Scholar 

  30. Suzuki, A. and N. Fukushima, Anti-sunward space current below the MAGSAT level during magnetic storms, J. Geomag. Geoelectr., 36, 493–506, 1984.

    Article  Google Scholar 

  31. Suzuki, A., M. Yanagisawa, and N. Fukushima, Antisunward space current below the Magsat level during magnetic storms and its possible connection with partial ring current in the magnetosphere, J. Geophys. Res., 90(B3), 2465–2471, 1985.

    Article  Google Scholar 

  32. Wallis, D. D., J. R. Burrows, T. J. Hughes, and M. D. Wilson, Eccentric dipole coordinates for MAGSAT data presentation and analysis of external current effects, Geophys. Res. Lett., 9, 353–356, 1982.

    Article  Google Scholar 

  33. Yamada, Y., M. Takeda, and T. Araki, Field-aligned currents during northward interplanetary magnetic field, Memoirs Kakioka Mag. Obs., 23, 39–51, 1990 (in Japanese with English abstract).

    Google Scholar 

  34. Yamauchi, M. and T. Araki, The interplanetary magnetic field By-de-pendent field-aligned current in the dayside polar cap under quiet conditions, J. Geophys. Res., 94, 2684–2690, 1989.

    Article  Google Scholar 

  35. Yanagisawa, M., Derivation of crustal magnetic anomalies from MAGSAT, The Inst. Space and Astronautical Sci. Rep. No. 609, 1–65, 1984.

  36. Zanetti, L. J. and T. A. Potemra, Correlated Birkeland current signatures from the TRIAD and MAGSAT magnetic field data, Geophys. Res. Lett., 9, 349–352, 1982.

    Article  Google Scholar 

  37. Zanetti, L. J., T. A. Potemra, and M. Sugiura, Evaluation of high latitude disturbances with MAGSAT (The importance of the MAGSAT geo-magnetic field model), Geophys. Res. Lett., 9, 365–368, 1982.

    Article  Google Scholar 

  38. Zanetti, L. J., W. Baumjohann, and T. A. Potemra, Ionospheric and Birkeland current distributions inferred from the MAGSAT magne-tometer data, J. Geophys. Res., 88, 4875–4884, 1983.

    Article  Google Scholar 

  39. Zanetti, L. J., T. A. Potemra, T. Iijima, W. Baumjohann, and P. F. Bythrow, Ionospheric and Birkeland current distributions for north-ward interplanetary magnetic field: inferred polar convection, J. Geophys. Res., 89, 7453–7458, 1984.

    Article  Google Scholar 

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Correspondence to Akira Suzuki.

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Suzuki, A., Fukushima, N. Space current around the earth obtained with Ampère’s law applied to the MAGSAT orbit and data. Earth Planet Sp 50, 43–56 (1998). https://doi.org/10.1186/BF03352085

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Keywords

  • Interplanetary Magnetic Field
  • Magnetic Storm
  • Geomagnetic Disturbance
  • Auroral Zone
  • Auroral Oval