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-EM13] Dynamics of the Inner Magnetospheric System

Wed. May 28, 2025 10:45 AM - 12:15 PM 302 (International Conference Hall, Makuhari Messe)

convener:Kunihiro Keika(Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo ), Yoshizumi Miyoshi(Institute for Space-Earth Environmental Research, Nagoya University), Jerry Goldstein(Southwest Research Institute), YIXIN Sun(Peking University), Chairperson:Kazuhiro Yamamoto(Institute for Space-Earth Environmental Research), Kunihiro Keika(Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo), Claudia Martinez-Calderon(Nagoya University)


11:45 AM - 12:00 PM

[PEM13-10] OI(1D) and N21PG spectra of the red aurora observed by hyperspectral camera (HySCAI)

*Katsumi Ida1, Mikirou Yoshinuma1, Yusuke Ebihara2 (1.National Institute for Fusion Science, 2.Research Institute for Sustainable Humanosphere, Kyoto University,)

Keywords:Hyperspectral camera, red aurora, N2 1PG, vibrational rotation levels

The hyperspectral camera for auroral imaging (HySCAI) has been installed at the KEOPS (Kiruna Esrange Optical Platform Site) of the SSC (Swedish Space Corporation) in Kiruna, Sweden [1,2]. The HySCAI can provide a two-dimensional (2D) aurora image with a full spectrum, which was developed to study auroral physics. HySCAI consists of an all-sky lens, monitor camera, galvanometer scanner, grating spectrograph, and electron-multiplying charge-coupled device (EM-CCD). The galvanometer scanner can scan a slit image of the spectrograph on the all-sky image plane in the direction perpendicular to the slit. HySCAI has two gratings; one is 500 grooves/mm for a wide spectral coverage of 400–800 nm with a spectral resolution (FWHM) of 2.1 nm, and the other is 1500 grooves/mm for a higher spectral resolution of 0.73 nm with a narrower spectral coverage of 123 nm. Poleward expansion of bright aurora was observed to begin at KEOPS at ~17:30 UT on January 1, 2025, which is associated with a large substorm as manifested by the quick look AE index over 1000 nT. The bright aurora reached overhead of KEOPS at ~17:35 UT, and the reddish aurora became prominent. The prominence of the red aurora lasted about 50 minutes. We investigated the temporal evolution of the spectrum (620 – 720 nm) of the red aurora, in particular, at the OI (1D) 630.0 nm line and the bands of the vibrational rotation levels of the N2 1PG molecules (8,5) 646.7 nm, (7,4) 654.5 nm, (6,3) 662.6 nm, (5,2) 670.1 nm, (4,1) 679.0 nm and (3,0) 687.6 nm. From 17:36 UT to 17:42 UT, the OI (1D) 630.0nm line glowed largely, whereas the intensity of N2 1PG gradually decreased. The ratios of each band of vibrational rotation levels of the N2 1PG molecule were not constant during this interval. The time variation of the ratio normalized by the intensity at (5,2) 670.1 nm shows that (4,1) 679.0 nm and (6,3) 662.6 nm increased just before this interval and decreased during this interval. As for the ratio normalized by the intensity at (5,2) 670.1 nm, the intensity at (8,5) 646.7 nm, (7,4) 654.5 nm, and (3,0) 687.6 nm decreases before this interval and increases during this interval. This time evolution of the ratio suggests that the parameters of the plasma in the N2 1PG emission region are changing [3].
[1] Homepage https://projects.nifs.ac.jp/aurora/en/
[2] M.Yoshinuma, K.Ida, Y.Ebihara, Earth, Planets and Space 76 (2024) 96.
https://www.eurekalert.org/news-releases/1052684
https://sj.jst.go.jp/news/202410/n1007-01k.html
[3] J.S. Morrill, and W.M. Benesch, J. Geophys. Res. 101 (1996) 261