Russian Journal of Earth Sciences Russian Journal of Earth Sciences Russian Journal of Earth Sciences 1681-1208 46866 ОРИГИНАЛЬНЫЕ СТАТЬИ ORIGINAL ARTICLES ОРИГИНАЛЬНЫЕ СТАТЬИ Statistical maps of field-aligned currents inferred from Swarm: dependence on season and interplanetary magnetic field Statistical maps of field-aligned currents inferred from Swarm: dependence on season and interplanetary magnetic field Lukianova R Yu Lukianova R Yu Bogoutdinov Sh R Bogoutdinov Sh R Geophysical Center of the Russian Academy of Sciences GC RAS ru Geophysical Center of the Russian Academy of Sciences GC RAS ru Geophysical Center of the Russian Academy of Sciences GC RAS ru Geophysical Center of the Russian Academy of Sciences GC RAS ru 18 6 1 11 10 11 2021 https://rjes.ru/en/nauka/article/46866/view

We report the initial results of the statistical analysis of field-aligned currents FACs observed above the ionosphere by the~low-Earth polar-orbiting Swarm satellite. FACs are the main electrodynamic agent of the solar wind-magnetosphere-ionosphere coupling. FACs flow along the high-conducting geomagnetic field lines between the magnetospheric boundary layers and the auroral ionosphere. A series of the~Swarm-based statistical maps of large-scale FACs~are constructed, resolving the seasonal dependences of the FAC distribution under conditions of the northward and southward interplanetary magnetic field IMF, low solar activity and the total IMF strength of 1-2~nT on average. The conventional R0/R1/R2 system is the dominant feature in the dark and sunlit polar ionosphere. The upward/downward current densities are well balanced within a given hemisphere, demonstrating a reasonable rate of elevation, going from winter to summer and from positive to negative IMF. The FAC intensities are larger by a factor of 1.6 in the summer hemisphere in comparison to the winter hemisphere.

We report the initial results of the statistical analysis of field-aligned currents FACs observed above the ionosphere by the~low-Earth polar-orbiting Swarm satellite. FACs are the main electrodynamic agent of the solar wind-magnetosphere-ionosphere coupling. FACs flow along the high-conducting geomagnetic field lines between the magnetospheric boundary layers and the auroral ionosphere. A series of the~Swarm-based statistical maps of large-scale FACs~are constructed, resolving the seasonal dependences of the FAC distribution under conditions of the northward and southward interplanetary magnetic field IMF, low solar activity and the total IMF strength of 1-2~nT on average. The conventional R0/R1/R2 system is the dominant feature in the dark and sunlit polar ionosphere. The upward/downward current densities are well balanced within a given hemisphere, demonstrating a reasonable rate of elevation, going from winter to summer and from positive to negative IMF. The FAC intensities are larger by a factor of 1.6 in the summer hemisphere in comparison to the winter hemisphere.

 solar wind-magnetosphere-ionosphere interaction field-aligned currents statistical maps Swarm satellites solar wind-magnetosphere-ionosphere interaction field-aligned currents statistical maps Swarm satellites

Anderson, B. J., Takahashi, K., Toth, B. A. Sensing global Birkeland currents with Iridium engineering magnetometer data, // Geophysical Research Letters, 2000. - v. 27 - no. 24 - p. 4045. Anderson, B. J., Takahashi, K., Toth, B. A. Sensing global Birkeland currents with Iridium engineering magnetometer data, // Geophysical Research Letters, 2000. - v. 27 - no. 24 - p. 4045. Anderson, B. J., Korth, H., Waters, C. L., et al. Statistical Birkeland current distributions from magnetic field observations by the Iridium constellation, // Annales Geophysique, 2008. - no. 26 - p. 671. Anderson, B. J., Korth, H., Waters, C. L., et al. Statistical Birkeland current distributions from magnetic field observations by the Iridium constellation, // Annales Geophysique, 2008. - no. 26 - p. 671. Birkeland, K. The Norwegian Aurora Polaris Expedition 1902#x2013;1903 - Christiania, Norway: H. Aschelhoug ampersand Co.., 1908. - 994 pp. Birkeland, K. The Norwegian Aurora Polaris Expedition 1902#x2013;1903 - Christiania, Norway: H. Aschelhoug ampersand Co.., 1908. - 994 pp. Bythrow, P. F., Potemra, T. A., Erlandson, R. E., et al. Birkeland currents and charged particles in the high-latitude prenoon region: A new interpretation, // Journal of Geophysical Research, 1988. - v. 93 - no. A9 - p. 9791. Bythrow, P. F., Potemra, T. A., Erlandson, R. E., et al. Birkeland currents and charged particles in the high-latitude prenoon region: A new interpretation, // Journal of Geophysical Research, 1988. - v. 93 - no. A9 - p. 9791. Christiansen, F., Papitashvili, V. O., Neubert, T. Seasonal variations of high-latitude field-aligned currents inferred from \Orsted and Magsat observations, // Journal of Geophysical Research, 2002. - v. 107 - no. A2 - p. SMP 5-1. Christiansen, F., Papitashvili, V. O., Neubert, T. Seasonal variations of high-latitude field-aligned currents inferred from \Orsted and Magsat observations, // Journal of Geophysical Research, 2002. - v. 107 - no. A2 - p. SMP 5-1. Edwards, T. R., Weimer, D. R., Tobiska, W. K., et al. Field-aligned current response to solar indices, // Journal of Geophysical Research: Space Physics, 2017. - v. 122 - no. 5 - p. 5798. Edwards, T. R., Weimer, D. R., Tobiska, W. K., et al. Field-aligned current response to solar indices, // Journal of Geophysical Research: Space Physics, 2017. - v. 122 - no. 5 - p. 5798. Farthing, W. H., Sugiura, M., Ledley, B. G., et al. Magnetic field observations on DE-A and -B, // Space Science Instrumentation, 1981. - v. 5 - p. 551. Farthing, W. H., Sugiura, M., Ledley, B. G., et al. Magnetic field observations on DE-A and -B, // Space Science Instrumentation, 1981. - v. 5 - p. 551. Fujii, R., Iijima, T., Potemra, T.A., Sugiura, M. Seasonal dependence of large-scale Birkeland currents, // Geophysical Research Letters, 1981. - v. 8 - no. 10 - p. 1103. Fujii, R., Iijima, T., Potemra, T.A., Sugiura, M. Seasonal dependence of large-scale Birkeland currents, // Geophysical Research Letters, 1981. - v. 8 - no. 10 - p. 1103. Fukushima, N. Generalized theorem for no ground magnetic effect of vertical currents connected with Pedersen currents in the uniform-conductivity ionosphere, // Report of Ionosphere and Space Research in Japan, 1976. - v. 30 - no. 1#x2013;2 - p. 35. Fukushima, N. Generalized theorem for no ground magnetic effect of vertical currents connected with Pedersen currents in the uniform-conductivity ionosphere, // Report of Ionosphere and Space Research in Japan, 1976. - v. 30 - no. 1#x2013;2 - p. 35. Gvishiani, A. D., Lukianova, R. Yu. Geoinformatics and Observations of the Earth's Magnetic Field: The Russian Segment, // Izvestiya: Physics of the Solid Earth, 2015. - v. 51 - no. 2 - p. 157. Gvishiani, A. D., Lukianova, R. Yu. Geoinformatics and Observations of the Earth's Magnetic Field: The Russian Segment, // Izvestiya: Physics of the Solid Earth, 2015. - v. 51 - no. 2 - p. 157. Haraguchi, K., Kawano, H., Yumoto, K., Ohtani, S., Higuchi, T., Ueno, G. Ionospheric conductivity dependence of dayside region-0, 1, and 2 field-aligned current systems: statistical study with DMSP-F7, // Annales Geophysicae, 2004. - no. 22 - p. 2775. Haraguchi, K., Kawano, H., Yumoto, K., Ohtani, S., Higuchi, T., Ueno, G. Ionospheric conductivity dependence of dayside region-0, 1, and 2 field-aligned current systems: statistical study with DMSP-F7, // Annales Geophysicae, 2004. - no. 22 - p. 2775. He, M., Vogt, J., L#xFC;hr, H., Sorbalo, E., Blagau, A., Le, G., Lu, G. A high-resolution model of field-aligned currents through empirical orthogonal functions analysis MFACE, // Geophysical Research Letters, 2012. - v. 39 - no. 18 - p. L18105 1. He, M., Vogt, J., L#xFC;hr, H., Sorbalo, E., Blagau, A., Le, G., Lu, G. A high-resolution model of field-aligned currents through empirical orthogonal functions analysis MFACE, // Geophysical Research Letters, 2012. - v. 39 - no. 18 - p. L18105 1. Iijima, T., Potemra, T. A. The amplitude distribution of field-aligned currents of northern high latitudes observed by Triad, // Journal of Geophysical Research, 1976. - v. 81 - no. 13 - p. 2165. Iijima, T., Potemra, T. A. The amplitude distribution of field-aligned currents of northern high latitudes observed by Triad, // Journal of Geophysical Research, 1976. - v. 81 - no. 13 - p. 2165. Korth, H., Anderson, B. J., Waters, C. L. Statistical analysis of the dependence of large-scale Birkeland currents on solar wind parameters, // Annales Geophysicae, 2010. - v. 28 - no. 2 - p. 515. Korth, H., Anderson, B. J., Waters, C. L. Statistical analysis of the dependence of large-scale Birkeland currents on solar wind parameters, // Annales Geophysicae, 2010. - v. 28 - no. 2 - p. 515. Langel, R. A., Estes, R. H. The near-earth magnetic field at 1980 determined from Magsat data, // Journal of Geophysical Research: Solid Earth, 1985. - v. 90 - no. B3 - p. 2495. Langel, R. A., Estes, R. H. The near-earth magnetic field at 1980 determined from Magsat data, // Journal of Geophysical Research: Solid Earth, 1985. - v. 90 - no. B3 - p. 2495. Lui, A. T. Y. Current disruption in the Earth's magnetosphere: Observations and models, // Journal of Geophysical Research: Space Physics, 1996. - v. 101 - no. A6 - p. 13067. Lui, A. T. Y. Current disruption in the Earth's magnetosphere: Observations and models, // Journal of Geophysical Research: Space Physics, 1996. - v. 101 - no. A6 - p. 13067. Lukianova, R., Hanuise, C., Christiansen, F. Asymmetric distribution of the ionospheric electric potential in the opposite hemispheres as inferred from the SuperDARN observations and FAC-based convection model, // Journal Atmospheric and Solar-Terrestrial Physics, 2008. - no. 70 - p. 2324. Lukianova, R., Hanuise, C., Christiansen, F. Asymmetric distribution of the ionospheric electric potential in the opposite hemispheres as inferred from the SuperDARN observations and FAC-based convection model, // Journal Atmospheric and Solar-Terrestrial Physics, 2008. - no. 70 - p. 2324. Lukianova, R. Yu., Kozlovsky, A., Christiansen, F. Asymmetric structures of field-aligned currents and convection of ionospheric plasma controlled by the IMF azimuthal component and season of year, // Geomagnetism and Aeronomy, 2010. - v. 50 - no. 5 - p. 667. Lukianova, R. Yu., Kozlovsky, A., Christiansen, F. Asymmetric structures of field-aligned currents and convection of ionospheric plasma controlled by the IMF azimuthal component and season of year, // Geomagnetism and Aeronomy, 2010. - v. 50 - no. 5 - p. 667. Lukianova, R., Kozlovsky, A. IMF $B_y$ effects in the plasma flow at the polar cap boundary, // Annales Geophysicae, 2011. - v. 29 - no. 7 - p. 1305. Lukianova, R., Kozlovsky, A. IMF $B_y$ effects in the plasma flow at the polar cap boundary, // Annales Geophysicae, 2011. - v. 29 - no. 7 - p. 1305. McGranaghan, R. M., Mannucci, A. J., Forsyth, C. A comprehensive analysis of multiscale field-aligned currents: Characteristics, controlling parameters, and relationships, // Journal of Geophysical Research: Space Physics, 2017. - v. 122 - no. 12 - p. 11,931. McGranaghan, R. M., Mannucci, A. J., Forsyth, C. A comprehensive analysis of multiscale field-aligned currents: Characteristics, controlling parameters, and relationships, // Journal of Geophysical Research: Space Physics, 2017. - v. 122 - no. 12 - p. 11,931. Neubert, T., Mandea, M., Hulot, G., von Frese, R., Primdahl, F. , et al., \Orsted satellite captures high-precision geomagnetic field data, // Eos Trans. AGU, 2001. - v. 82 - no. 7 - p. 81. Neubert, T., Mandea, M., Hulot, G., von Frese, R., Primdahl, F. , et al., \Orsted satellite captures high-precision geomagnetic field data, // Eos Trans. AGU, 2001. - v. 82 - no. 7 - p. 81. Olsen, N., Friis-Christensen, E., Floberghagen, R., et al., The SWARM satellite constellation application and research facility SCARF and SWARM data products, // Earth, Planets and Space, 2013. - no. 65 - p. 1189. Olsen, N., Friis-Christensen, E., Floberghagen, R., et al., The SWARM satellite constellation application and research facility SCARF and SWARM data products, // Earth, Planets and Space, 2013. - no. 65 - p. 1189. Papitashvili, V. O., Christiansen, F., Neubert, T. A new model of field-aligned currents derived from high-precision satellite magnetic field data, // Geophysical Research Letters, 2002. - v. 29 - no. 12 - p. 28-1. Papitashvili, V. O., Christiansen, F., Neubert, T. A new model of field-aligned currents derived from high-precision satellite magnetic field data, // Geophysical Research Letters, 2002. - v. 29 - no. 12 - p. 28-1. Reigber, C., L#xFC;hr, H., Schwintzer, P., Wickert, J. Earth Observation with CHAMP. Results from Three Years in Orbit - Berlin, Germany: Springer-Verlag., 2004. - 629 pp. Reigber, C., L#xFC;hr, H., Schwintzer, P., Wickert, J. Earth Observation with CHAMP. Results from Three Years in Orbit - Berlin, Germany: Springer-Verlag., 2004. - 629 pp. Ritter, P., L#xFC;hr, H., Rauberg, J. Determining field-aligned currents with the Swarm constellation mission, // Earth, Planets and Space, 2013. - no. 65 - p. 1285. Ritter, P., L#xFC;hr, H., Rauberg, J. Determining field-aligned currents with the Swarm constellation mission, // Earth, Planets and Space, 2013. - no. 65 - p. 1285. Robinson, R. M., Vondrak, R. R. Measurements of $E$ region ionization and conductivity produced by solar illumination at high latitudes, // Journal of Geophysical Research: Space Physics, 1984. - v. 89 - no. A6 - p. 3951. Robinson, R. M., Vondrak, R. R. Measurements of $E$ region ionization and conductivity produced by solar illumination at high latitudes, // Journal of Geophysical Research: Space Physics, 1984. - v. 89 - no. A6 - p. 3951. Ruohoniemi, J. M., Greenwald, R. A. Dependencies of high-latitude plasma convection: Consideration of IMF, seasonal, and UT factors in statistical patterns, // Journal of Geophysical Research, 2005. - v. 110 - no. A9 - p. A09204 1. Ruohoniemi, J. M., Greenwald, R. A. Dependencies of high-latitude plasma convection: Consideration of IMF, seasonal, and UT factors in statistical patterns, // Journal of Geophysical Research, 2005. - v. 110 - no. A9 - p. A09204 1. Siscoe, G., Maynard, N. Distributed two-dimensional region 1 and Region 2 currents: Model results and data comparisons, // Journal of Geophysical Research: Space Physics, 1991. - v. 96 - no. A12 - p. 21071. Siscoe, G., Maynard, N. Distributed two-dimensional region 1 and Region 2 currents: Model results and data comparisons, // Journal of Geophysical Research: Space Physics, 1991. - v. 96 - no. A12 - p. 21071. Swarm Level 2 Processing System Consortium., Detailed Processing Model DPM FAC - Potsdam, Germany: GFZ., 2012. Swarm Level 2 Processing System Consortium., Detailed Processing Model DPM FAC - Potsdam, Germany: GFZ., 2012. Weimer, D. R. Maps of ionospheric field-aligned currents as a function of the interplanetary magnetic field derived from Dynamics Explorer 2 data, // Journal of Geophysical Research: Space Physics, 2001. - v. 106 - no. A7 - p. 12889. Weimer, D. R. Maps of ionospheric field-aligned currents as a function of the interplanetary magnetic field derived from Dynamics Explorer 2 data, // Journal of Geophysical Research: Space Physics, 2001. - v. 106 - no. A7 - p. 12889. Xiong, C., L#xFC;hr, H., Wang, H., Johnsen, M. G. Determining the boundaries of the auroral oval from CHAMP field-aligned current signatures~#x2013;~Part 1, // Annales Geophysicae, 2014. - v. 32 - no. 6 - p. 609. Xiong, C., L#xFC;hr, H., Wang, H., Johnsen, M. G. Determining the boundaries of the auroral oval from CHAMP field-aligned current signatures~#x2013;~Part 1, // Annales Geophysicae, 2014. - v. 32 - no. 6 - p. 609. Zanetti, L.J., Potemra, T.A., Iijima, T., et al. Ionospheric and Birkeland current distributions for northward interplanetary magnetic field - inferred polar convection, // Journal of Geophysical Research: Space Physics, 1984. - v. 89 - no. A9 - p. 7453. Zanetti, L.J., Potemra, T.A., Iijima, T., et al. Ionospheric and Birkeland current distributions for northward interplanetary magnetic field - inferred polar convection, // Journal of Geophysical Research: Space Physics, 1984. - v. 89 - no. A9 - p. 7453.