Japan Geoscience Union Meeting 2022

Presentation information

[E] Poster

P (Space and Planetary Sciences ) » P-EM Solar-Terrestrial Sciences, Space Electromagnetism & Space Environment

[P-EM10] Dynamics of Magnetosphere and Ionosphere

Thu. Jun 2, 2022 11:00 AM - 1:00 PM Online Poster Zoom Room (5) (Ch.05)

convener:Yuka Sato(Nippon Institute of Technology), convener:Akimasa Ieda(Institute for Space-Earth Environmental Research, Nagoya University), Akiko Fujimoto(Kyushu Institute of Technology), convener:Shun Imajo(Data Analysis Center for Geomagnetism and Space Magnetism, Graduate School of Science, Kyoto University), Chairperson:Yuka Sato(Nippon Institute of Technology), Akimasa Ieda(Institute for Space-Earth Environmental Research, Nagoya University), Akiko Fujimoto(Kyushu Institute of Technology), Shun Imajo(Data Analysis Center for Geomagnetism and Space Magnetism, Graduate School of Science, Kyoto University)


11:00 AM - 1:00 PM

[PEM10-P17] Comparison of Magnetic Variations Associated with the IHFAC Observed on the Ground and in the LEO

*Kentarou Kitamura1, Akiko Fujimoto1, Akimasa Yoshikawa2, Shuji Abe2 (1.Kyushu Institute of Technology, 2.Kyushu University)

Keywords:IHFAC, LEO satellite, Geomagnetic Field Observation

A global distribution of the ionospheric current has been studied by many investigators to understand the potential balance which is subsequentially produced by the tidal variations in the neutral atmosphere and imposed electric field from the magnetospheric disturbances. A primary vortex pattern of the current system is known as Sq current system which has potential peak near 20-30 deg in geomagnetic latitude at near noon sector. However, the potential pattern shows the north/south asymmetry depending on the season, that is, the intensity of the potential is stronger (weaker) in summer (winter) hemisphere. Regarding to such potential pattern, Fukushima (1979, 1991) theoretically predicted an existence of Inter-Hemispheric Field Aligned Currents (IHFAC) connecting between the potential peaks in both northern and southern hemispheres. However, the detailed morphology and physical process of the IHFAC have not been fully understand, though there were several ground and satellites observations (e.g. Yamashita and Iyemori, 2002, and Park et al., 2002).
Recently Ranasinghe et al.(2021) analyze a long term variation of the D-component magnetic variation at Davao (Geographical latitude 7 deg., Geographical longitude 124.5, Geomagnetic latitude -2.22 deg, Geomagnetic longitude 197.9 deg, Dip latitude -0.24 deg), and indicates that the direction of the IHFAC in the different local time shows the obvious seasonal variations. In particular, the obtained directions of IHFAC at the evening sector during September – November shows southward, which is inconsistent with the IHFAC model proposed by Fukushima (1979, 1991).
In this study, we analyze the data of Vector Field Magnetometer (VFM) onboard the Swam satellites to compare the characteristics of the IHFAC obtained from ground magnetometer data. The E-component (eastward) magnetic field variations in the NEC coordinate system from 2014 to 2021 is used in this study. We calculate the magnetic data obtained at a confined region of -5 < Lat < 5 (degree), and 115 < Long < 135 (degree) where Davao station is mostly centered.
As a result, the E-component magnetic field shows positive deviations in the dusk sectors from September to December, whereas it shows negative deviations from May to July. This signature is basically consistent with the observation on the ground by Ranasinghe et al. The result suggests the altitude of the IHFAC at equatorial region is higher than 510km of the altitude of Swam orbit. Moreover, this study implies the possibility to the more affordable observation in LEO by nano-satellites.