Low-Latitude Auroras: Insights from 23 April 2023 Solar Storm
In April 2023, low-latitude aurora observation by the all-sky camera at Hanle, Ladakh, India ($33^{\circ} {} N $ geographic latitude (GGLat)) was reported, which stimulated a lot of discussion among scientists as well as masses across the globe. The reported observation was intriguing as the solar s...
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Main Authors | , , , , , , |
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Format | Journal Article |
Language | English |
Published |
25.04.2024
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Subjects | |
Online Access | Get full text |
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Summary: | In April 2023, low-latitude aurora observation by the all-sky camera at
Hanle, Ladakh, India ($33^{\circ} {} N $ geographic latitude (GGLat)) was
reported, which stimulated a lot of discussion among scientists as well as
masses across the globe. The reported observation was intriguing as the solar
storm that triggered this aurora was moderate and the first such observation
from Indian region in the space-era. In this communication, we investigate such
a unique modern-day observation of low-latitude auroral sighting occurring
during the passage of sheath-region of Interplanetary-Coronal-Mass-Ejection,
utilizing in situ multi-spacecraft particle measurements along with
geomagnetic-field observations by ground and satellite-based magnetometers.
Auroral observations at Hanle coincided with the intense substorm occurrences.
It is unequivocally found that the aurora didnt reach India, rather the
equatorward boundary of the aurora was beyond $ 50^{\circ} {}N $ GGLat. The
multi-instrumental observations enabled us to estimate the altitude of the red
auroral emissions accurately. The increased flux of low-energy electrons
($<$100 eV) precipitating at $\sim 54^{\circ}N$ GGLat causing red-light
emissions at higher altitudes ($\sim$700-950 km) can be visible from Hanle. The
observed low-latitude red aurora from India resulted from two factors:
emissions at higher altitudes in the auroral oval and a slight expansion of the
auroral oval towards the equator. The precipitating low-energy particles
responsible for red auroral emissions mostly originate from the plasma sheet.
These particles precipitate due to wave-particle interactions enhanced by
strong compression of the magnetosphere during high solar wind pressure. This
study using multi-point observations holds immense importance in providing a
better understanding of low-latitude auroras. |
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DOI: | 10.48550/arxiv.2405.08821 |