Equatorward Moving Auroral Arcs Associated with Impulse-Excited Field Line Resonance

The theory of equatorward moving east-west elongated auroral arcs associated with field line resonance (FLR) has been proposed for decades. However, confirming this theory requires in-situ observations of FLR within the magnetosphere and simultaneous all-sky imager observations of equatorward moving...

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Bibliographic Details
Published in:Universe
Main Authors: Huayu Zhao, Ying Liu, Huigen Yang, Qiugang Zong, Zejun Hu, Xuzhi Zhou, Yongfu Wang, Jicheng Sun, Bin Li
Format: Article in Journal/Newspaper
Language:English
Published: MDPI AG 2023
Subjects:
equatorward moving aurora
solar wind dynamic pressure pulse
field line resonance
Elementary particle physics
QC793-793.5
Zhongshan
Zhongshan Station
Antarc*
Antarctica
Online Access:https://doi.org/10.3390/universe9060249
https://doaj.org/article/e5008352d1234108b8f19e55abad82f5
Description
Summary:The theory of equatorward moving east-west elongated auroral arcs associated with field line resonance (FLR) has been proposed for decades. However, confirming this theory requires in-situ observations of FLR within the magnetosphere and simultaneous all-sky imager observations of equatorward moving auroral arcs near satellite footpoints. In this study, we present the first observations of multiple equatorward moving auroral arcs related to impulse-excited FLR, using datasets from the WIND, Geotail satellites, and an all-sky imager at China’s Zhongshan Station (ZHS) in Antarctica. In the presented event, the ultra-low-frequency waves associated with solar wind dynamic pressure pulse was mainly toroidal mode, which is consistent with the theory that the toroidal mode waves usually related with external source. The all-sky imager located in Zhongshan station recorded several equatorward moving auroral arcs, followed by reverse propagating ones. The latitudinal width of the equatorward moving auroral arcs was on the order of 25 km and had an average equatorward propagation of ~0.37 km/s, which is very similar to the value from previous work. To better illustrate the observed evolution of auroral arcs related with the FLRs we proposed a simple model to evaluate the FACs induced by the FLRs in different latitudes. The latitudinal distribution evolution of FACs agrees well with the ground-based optical observations.

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