Japan Geoscience Union Meeting 2021

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[J] Oral

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

[P-EM14] Heliosphere and Interplanetary Space

Sat. Jun 5, 2021 1:45 PM - 3:15 PM Ch.06 (Zoom Room 06)

convener:Kazumasa Iwai(Institute for Space–Earth Environmental Research (ISEE), Nagoya University), Yasuhiro Nariyuki(Faculty of Education, University of Toyama), Ken Tsubouchi(University of Electro-Communications), N Masaki Nishino(Japan Aerospace Exploration Agency, Institute of Space and Astronautical Science), Chairperson:Yasuhiro Nariyuki(Faculty of Education, University of Toyama), Masaki N Nishino(Japan Aerospace Exploration Agency, Institute of Space and Astronautical Science)

2:30 PM - 2:45 PM

[PEM14-10] Elliptically polarized 0.01-0.3 Hz magnetic field variation in the lunar wake

*Tomoko Nakagawa1, Futoshi Takahashi2, Hisayoshi Shimizu3, Yoshifumi Saito4 (1.Information and Communication Engineering, Tohoku Institute of Technology, 2.Department of Earth and Planetary Sciences, Faculty of Science, Kyushu University, 3.Earthquake Research Institute, University of Tokyo, 4.Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency)

Keywords:moon, lunar wake, polarization, magnetic field variation, ion cyclotron frequency, Kaguya

Elliptically polarized magnetic field variation in the frequency range of 0.01-0.3 Hz was detected by Kaguya MAP-LMAG in the lunar wake. The polarization was highly elliptic and the direction of rotation was consistent with the vortex behind an obstacle in a fast flow, but no clear vortex motion was found in ion velocity observed by MAP-PACE onboard Kaguya. The magnetic variation was compressional, and the wave number vector was nearly parallel or oblique to the background magnetic field. The waves persisted in the deepest wake, suggesting that they were not surface waves. High frequency components above the local ion cyclotron frequency exhibited circular polarization of right-handed or left-handed rotation with respect to the background magnetic field.