[P-EM12] Dynamics of the Inner Magnetospheric System

[PEM12-16] Mode-coupling Pi2 pulsations on the off-equatorial plasmapause inferred from the Arase satellite observation

*Mariko Teramoto¹, Ayako Matsuoka², Yoshiya Kasahara³, Yasumasa Kasaba⁴, Atsushi Kumamoto⁴, Fuminori Tsuchiya⁴, Shoya Matsuda⁶, Yoshizumi Miyoshi⁵, Masahito Nose⁵, Tomoko Nakagawa⁷, Shun Imajo⁵, Masafumi Shoji⁵, Satoko Nakamura⁵, Iku Shinohara⁶ (1.Kyushu Institute of Technology, 2.Kyoto University, 3.Kanazawa University, 4.Tohoku University, 5.Nagoya University, 6.Japan Aerospace Exploration Agency, Institute of Space and Astronautical Science, 7.Tohoku Institute of Technology)

We investigated Pi2 pulsations in the electric and magnetic field and their relation to the ambient plasma density observed from the Arase satellite to explore the generation mechanism of low-latitude Pi2. At a geomagnetically quiet time, Pi2 pulsations were observed in all three components of the magnetic field and in the radial and azimuthal components of the electric field when the Arase satellite was located on the plasmapause off the equatorial plane (about 25 degrees Mlat) at midnight. The coherence and cross phase between the orthogonal electric and magnetic field components are high and approximately 90 degrees. The compressional component of the magnetic field has high coherence with the azimuthal component of the electric field. The cross phase properties indicate that the radial and field-aligned standing waves are excited on the plasmapause. These results confirm the mode coupling between the fast mode wave and Alfven waves in the plasmasphere, which was proposed by Takahashi et al. [2018].

We compared these Pi2 pulsations with those on the ground over a wide latitudinal and longitudinal range. Additionally, we discussed the generation mechanism of this event.