Low-Latitude Auroras: Insights from 23 April 2023 Solar Storm

Fuente: arXiv
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Main Authors: Vichare, Geeta, Bhaskar, Ankush, Rawat, Rahul, Yadav, Virendra, Mishra, Wageesh, Angchuk, Dorje, Singh, Anand Kumar
Format: Preprint
Published: 2024
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author Vichare, Geeta
Bhaskar, Ankush
Rawat, Rahul
Yadav, Virendra
Mishra, Wageesh
Angchuk, Dorje
Singh, Anand Kumar
author_facet Vichare, Geeta
Bhaskar, Ankush
Rawat, Rahul
Yadav, Virendra
Mishra, Wageesh
Angchuk, Dorje
Singh, Anand Kumar
contents 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.
format Preprint
id arxiv_https___arxiv_org_abs_2405_08821
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Low-Latitude Auroras: Insights from 23 April 2023 Solar Storm
Vichare, Geeta
Bhaskar, Ankush
Rawat, Rahul
Yadav, Virendra
Mishra, Wageesh
Angchuk, Dorje
Singh, Anand Kumar
Space Physics
Earth and Planetary Astrophysics
Solar and Stellar Astrophysics
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.
title Low-Latitude Auroras: Insights from 23 April 2023 Solar Storm
topic Space Physics
Earth and Planetary Astrophysics
Solar and Stellar Astrophysics
url https://arxiv.org/abs/2405.08821