Japan Geoscience Union Meeting 2022

Presentation information

[E] Oral

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

[P-EM10] Dynamics of Magnetosphere and Ionosphere

Thu. May 26, 2022 9:00 AM - 10:30 AM 303 (International Conference Hall, Makuhari Messe)

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:Hiroshi Hasegawa(Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency), Masaki N Nishino(Japan Aerospace Exploration Agency/Institute of Space and Astronautical Science)


10:00 AM - 10:15 AM

[PEM10-04] Disruption of accumulated northward IMF lines in the dayside magnetosheath due to discontinuous southward turning of IMF

*Tsubasa Hashimoto1, Akimasa Yoshikawa2, Takashi Tanaka3 (1.Graduate School of Science, Kyushu University, 2.Department of Earth and Planetary Sciences, Kyushu University, 3.International Center for Space Weather Science and Education)


Keywords:reconnection, discontinuous direction changes of IMF

Previous observations and models had shown that discontinuous direction changes of Interplanetary Magnetic Field (IMF) occur the dayside reconnection in the magnetosheath. We reproduced the dayside reconnection in the magnetosheath and the effect at the high latitude magnetosheath with a numerical simulation.
Using the Reproduce Plasma Universe (REPPU) code (Tanaka, 2015), we examined the structure of magnetic field lines in the magnetosheath when IMF turns to southward discontinuously. At first, we ran the simulation under IMF Bz = +5nT for 110 minutes to obtain a quasi-steady magnetosphere. Then, we changed IMF Bz = -3nT. As a result, we could show that the dayside reconnection in the magnetosheath occurs by the deceleration of the discontinuous surface and formation of the antiparallel magnetic structure. This reconnection has continued to completely disrupt accumulated northward IMF lines in the magnetosheath for about 8 minutes. After this process, the magnetic field lines are generated, both ends of which extend to the solar wind region. In addition, these lines are transported to the high latitude magnetosheath and occur the new reconnection with the lobe magnetic field lines. This reconnection has occurred for about 8 minutes and it becomes a quasi-steady magnetosheath under the southward IMF gradually. However, these reconnections have not always occurred for 8 minutes. In the presentation, we discuss a reconnection time universality when we add to IMF By or changed the dynamic pressure.