2026-08-28 総合研究大学院大学
図 1：先行研究および本研究で示したモデルの概要。真夜中前（夕方側）ではコーラス波の発生そのものが少ない。真夜中付近になるとコーラス波が発生し、脈動オーロラも出現する。真夜中以降（朝側）では、ダクトによるコーラス波の長距離伝搬と超高エネルギー電子散乱、およびパッチ状脈動オーロラの発生が多くなる。
＜関連情報＞
- https://www.soken.ac.jp/news/2026/20260828.html
- https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2026JA035231
地上画像装置とアラセ衛星の共役観測に基づく脈動オーロラと高緯度におけるコーラス波伝播に関する統計的研究 Statistical Study on Pulsating Auroras and High-Latitude Propagation of Chorus Waves Based on Conjugate Observations of Ground-Based Imagers and Arase Satellite
Y. Ito, Y. Ogawa, M. Fukizawa, Y. Tanaka, A. Kadokura, Y. Miyoshi, K. Hosokawa, A. Shinbori, T. Hori, Y. Kasahara, S. Matsuda, F. Tsuchiya, A. Kumamoto, A. Matsuoka, M. Teramoto, K. Yamamoto, I. Shinohara
Journal of Geophysical Research: Space Physics Published: 02 July 2026
DOI:https://doi.org/10.1029/2026JA035231
Abstract
Pulsating aurora (PsA) is one of the common diffuse auroras typically generated by ∼10 keV electron precipitation. Precipitating electrons are scattered via wave-particle interactions with whistler-mode chorus waves in the magnetosphere. Previous studies have observationally demonstrated that, during PsAs, highly energetic electrons with energies ranging from a few hundred keV to a few MeV simultaneously penetrate into lower altitudes and can cause ozone depletion in the mesosphere and upper stratosphere. Recent attention has focused on the importance of high-latitude propagation of chorus waves through magnetospheric density ducts for the precipitation of such highly energetic electrons. Our previous study showed that patchy structures of PsAs reflect the cross section of ducts. However, no statistical study has examined the relationship between ducted propagation of chorus waves and PsAs using ground-satellite conjugate observations. Thus, we perform a statistical analysis to evaluate this relationship using data from the ground-based optical network in Scandinavia and the Arase satellite. The results show that when chorus waves propagate to higher latitudes while maintaining their electromagnetic properties, PsAs exhibit patchy structures with more than 90% probability, and occurrence increases from midnight to the morning sector. In addition, the background electron density irregularities indicative of ducts were also observed in four events during high-latitude propagation of electromagnetic chorus waves. For these events, the equatorial projection sizes of PsA patches ranged from several hundred to several thousand kilometers, comparable to the scale required to confine chorus waves. These observations suggest the horizontal scale of ducts at the magnetic equator.
