Japan Geoscience Union Meeting 2018

Presentation information

[EE] Oral

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

[P-EM16] Dynamics of Earth's Inner Magnetosphere and Initial Results from Arase

Mon. May 21, 2018 1:45 PM - 3:15 PM 303 (3F International Conference Hall, Makuhari Messe)

convener:Danny Summers(Memorial University of Newfoundland), Yoshizumi Miyoshi(Institute for Space-Earth Environmental Research, Nagoya University), Keisuke Hosokawa(電気通信大学大学院情報理工学研究科, 共同), Yusuke Ebihara(Research Institute for Sustainable Humanosphere, Kyoto University), Chairperson:Miyoshi Yoshizumi(ISEE, Nagoya University)

2:45 PM - 3:00 PM

[PEM16-11] VLF Conjugate events between Arase (ERG) and Kannuslehto: differences between cases on the noon and midnight sides.

*Claudia Martinez Calderon1, Yuto Katoh1, Kazuo Shiokawa2, Mitsunori Ozaki3, Satoshi Kurita2, Jyrki Manninen4, Yoshiya Kasahara3, Shoya Matsuda2, Atsushi Kumamoto1, Fuminori Tsuchiya1, Ayako Matsuoka5, Yoshizumi Miyoshi2 (1.Dept. Geophys., Grad. Sch. Sci., Tohoku University, 2.Institute for Space-Earth Environmental Research, Nagoya, Japan, 3.Kanazawa, University, Kanazawa, Japan, 4.Sodankyl Geophysical Observatory, University of Oulu, Sodankyla, Finland, 5.Institute of Space and Astronautical Science, JAXA, Japan)

Keywords:VLF, Arase , Conjugate event, ERG, QP, whistler-mode

Quasi-periodic (QP) emissions, are naturally occurring magnetospheric plasma waves (3 Hz < f < 30 kHz) propagating in the whistler-mode with a fairly regular periodic modulation of their wave intensity. Through wave-particle interactions, whistler-mode waves play an important role in the regulation of radiation belt dynamics. Understanding the processes behind their generation and propagation, including their spatial extent, can help us quantify their part in the acceleration and scattering of electrons in the radiation belts. This study presents two rare QP conjugate events between the ground station of Kannuslehto [MLAT=64.4N, L=5.3], Finland, and the Arase (ERG) satellite. Case 1 on March 28, 2017 from ~22:30 to 23:00 UT, happened on the post-midnight side and during the recovery phase of a storm with a period of sustained high solar-wind speed and high AE (400 < AE < 800 nT). Case 2 on November 30, 2017 from ~09:30 to 10:20 UT was observed on the noon side, during a geomagnetic quiet time with a Dst > 10 nT and AE < 100 nT. Using these events, we estimated the size and characteristics of the active wave source for each event, the region where the waves are generated with the same frequency and spectral features. We discuss the coherence and spatial extent of the waves, and their local source size. We also investigate the role that density plays in the variations in the spectral features of the observed waves. We use correlation and wave analysis to compare wave propagation between the two cases. Finally, we discuss electron pitch angle distributions. This study presents the first opportunity to compare two conjugate events between the same ground-station and satellite, at different geomagnetic conditions and on almost opposite sides of the magnetosphere.