Variability of Quiet-Time Magnetic Field Intensity Reconstructed from Spherical Harmonic Coefficients Over Asian-Sub Region

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@article{1708442,
      author = {Mustapha Abbas, Mohammed Bello Kaoje, Mukhtar Mohammed, Mukhtar Ibrahim Furfuri, Aminu Yusuf Koko; Aminu Muhammad},
      title = {Variability of Quiet-Time Magnetic Field Intensity Reconstructed from Spherical Harmonic Coefficients Over Asian-Sub Region},
      journal = {Iconic Research And Engineering Journals},
      year = {2025},
      volume = {8},
      number = {11},
      pages = {1819-1827},
      issn = {2456-8880},
      url = {https://www.irejournals.com/formatedpaper/1708442.pdf},
      abstract = {The study used the quiet-time geomagnetic field records for the three orthogonal components (H, D and Z) during period of low solar activity year 2017. The quiet field records are uniquely separated into external and internal contributions using the spherical harmonic analysis (SHA) technique. The result shows that the intensity of the external (MSqHext), internal (MSqHint), and sum of the quiet field (MSqHTot), equator-ward of the Sq focus are bounded by daytime eastward current which decreases away from the equator and those pole-ward of the Sq focus are bounded by westward current which seems to increases with increasing latitudes. At low latitudes, there was a significant intrusion of the opposite hemisphere summertime external Sq current system into the wintertime hemisphere at pre-noon hours. The (MSqDext), amplitude consistently appeared stronger (weaker) in summer (winter) months reflecting marked effect of ionospheric conductivity caused by solar ionizing flux. The exceptionally large MSqZext, amplitude at KNY is associated with the reduced and slight phase shift of MSqHext, amplitude at KNY latitude. The result further revealed that the internal Sq focal latitude is consistently more pole-ward that their corresponding external Sq focus which may possibly reflect electromagnetic induction effect.},
      keywords = {Ionosphere, Sq current, magnetic field},
      month = {May},
  }