Japan Geoscience Union Meeting 2025

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[E] Oral

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

[P-EM12] Coupling Processes in the Atmosphere-Ionosphere System

Mon. May 26, 2025 3:30 PM - 5:00 PM 303 (International Conference Hall, Makuhari Messe)

convener:Keisuke Hosokawa(Department of Communication Engineering and Informatics, University of Electro-Communications), Huixin Liu(Earth and Planetary Science Division, Kyushu University SERC, Kyushu University), Yuichi Otsuka(Institute for Space-Earth Environmental Research, Nagoya University), Loren Chang(Department of Space Science and Engineering, National Central University), Chairperson:Takanori Nishiyama(National Institute of Polar Research), Yang-Yi Sun(China University of Geosciences)


3:30 PM - 3:45 PM

[PEM12-37] Ionospheric response to the competition between penetration electric field and thermospheric O/N2

★Invited Papers

*Yongliang Zhang1 (1.Johns Hopkins University Applied Physics Laboratory)

Keywords:Thermosphere composition (O/N2 ratio), Topside ionosphere, Penetration electric field, Thermospheric FUV emission, geomagentic storm, interplanetary electric field

We revisited the November 2004 superstorm by analyzing TIMED/GUVI data which provide information of both thermosphere and ionosphere. When an intense eastward Interplanetary
Electric Field (IEF) or Penetration Electric Field (PEF) occurred,
the dayside equatorial arcs were enhanced and their latitude separation increased.
The enhanced equatorial arcs were hemispherically symmetric or asymmetric in the region with non-depleted O/
N2 or hemispherically asymmetric O/N2 depletion, respectively. When O/N2 depletion reached the magnetic
equator, there was no observable enhancement in the equatorial arcs regardless the IEF or PEF conditions, indicating O/N2 condition significantly modulated the variations in storm-time equatorial arcs. GUVI observations also showed that a westward IEF (PEF) and/or disturbance dynamo electric field could also suppress the dayside equatorial arcs.