Low-latitude Auroras: Insights from 2023 April 23 Solar Storm
In 2023 April, a low-latitude aurora observed by the all-sky camera at Hanle, Ladakh, India (33°14’N geographic latitude), generated significant interest. This was the first such aurora recorded from the Indian region in the space era and occurred during a moderate solar storm. This study explores t...
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2024-01-01
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| Online Access: | https://doi.org/10.3847/1538-4357/ad8dd3 |
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| author | Geeta Vichare Ankush Bhaskar Rahul Rawat Virendra Yadav Wageesh Mishra Dorje Angchuk Anand Kumar Singh |
| author_facet | Geeta Vichare Ankush Bhaskar Rahul Rawat Virendra Yadav Wageesh Mishra Dorje Angchuk Anand Kumar Singh |
| author_sort | Geeta Vichare |
| collection | DOAJ |
| description | In 2023 April, a low-latitude aurora observed by the all-sky camera at Hanle, Ladakh, India (33°14’N geographic latitude), generated significant interest. This was the first such aurora recorded from the Indian region in the space era and occurred during a moderate solar storm. This study explores this low-latitude auroral sighting, which happened during the sheath-region passage of an interplanetary coronal mass ejection. We analyze in situ multispacecraft particle measurements and geomagnetic field observations from both ground-based and satellite-based magnetometers. The auroral observations at Hanle coincided with intense substorm activity. Our findings indicate that the aurora did not actually reach India; the equatorward boundary was beyond 50°N geographic latitude. Enhanced electron fluxes with energies below 100 eV were detected at 54°N geographic latitude at about 830 km altitude in the predawn sector (4–5 hr local time). In the midnight sector, the equatorward boundary is estimated to be around 52°N geographic latitude, based on Hanle observations and considering emission altitudes of 600–650 km due to low-energy electrons. Thus, the low-latitude red aurora observed from India resulted from the emissions at higher altitudes due to low-energy electron precipitation in the auroral oval and a slight equatorward expansion of the auroral oval. The low-energy electrons likely originated from the plasma sheet and were precipitated due to enhanced wave–particle interactions from strong magnetosphere compression during high solar wind pressure. This study is crucial in understanding low-latitude auroras in the modern space era. |
| format | Article |
| id | doaj-art-38d7bf97f2f048dfb5b854c8af290780 |
| institution | DOAJ |
| issn | 1538-4357 |
| language | English |
| publishDate | 2024-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal |
| spelling | doaj-art-38d7bf97f2f048dfb5b854c8af2907802025-08-20T02:49:58ZengIOP PublishingThe Astrophysical Journal1538-43572024-01-01977217110.3847/1538-4357/ad8dd3Low-latitude Auroras: Insights from 2023 April 23 Solar StormGeeta Vichare0https://orcid.org/0000-0003-3607-6923Ankush Bhaskar1https://orcid.org/0000-0003-4281-1744Rahul Rawat2Virendra Yadav3https://orcid.org/0000-0002-9058-1835Wageesh Mishra4Dorje Angchuk5Anand Kumar Singh6Indian Institute of Geomagnetism , Navi Mumbai, Maharashtra, India ; geeta.vichare@iigm.res.inSpace Physics Laboratory, ISRO/Vikram Sarabhai Space Centre , Thiruvananthapuram, IndiaIndian Institute of Geomagnetism , Navi Mumbai, Maharashtra, India ; geeta.vichare@iigm.res.inAryabhatta Research Institute of Observational Sciences , Nainital, Uttarakhand, IndiaIndian Institute of Astrophysics , Bengaluru, Karnataka, IndiaIndian Institute of Astrophysics , Bengaluru, Karnataka, IndiaNational Centre for Polar and Oceanic Research , Goa, IndiaIn 2023 April, a low-latitude aurora observed by the all-sky camera at Hanle, Ladakh, India (33°14’N geographic latitude), generated significant interest. This was the first such aurora recorded from the Indian region in the space era and occurred during a moderate solar storm. This study explores this low-latitude auroral sighting, which happened during the sheath-region passage of an interplanetary coronal mass ejection. We analyze in situ multispacecraft particle measurements and geomagnetic field observations from both ground-based and satellite-based magnetometers. The auroral observations at Hanle coincided with intense substorm activity. Our findings indicate that the aurora did not actually reach India; the equatorward boundary was beyond 50°N geographic latitude. Enhanced electron fluxes with energies below 100 eV were detected at 54°N geographic latitude at about 830 km altitude in the predawn sector (4–5 hr local time). In the midnight sector, the equatorward boundary is estimated to be around 52°N geographic latitude, based on Hanle observations and considering emission altitudes of 600–650 km due to low-energy electrons. Thus, the low-latitude red aurora observed from India resulted from the emissions at higher altitudes due to low-energy electron precipitation in the auroral oval and a slight equatorward expansion of the auroral oval. The low-energy electrons likely originated from the plasma sheet and were precipitated due to enhanced wave–particle interactions from strong magnetosphere compression during high solar wind pressure. This study is crucial in understanding low-latitude auroras in the modern space era.https://doi.org/10.3847/1538-4357/ad8dd3AuroraeSolar particle emissionSolar stormSolar coronal mass ejections |
| spellingShingle | Geeta Vichare Ankush Bhaskar Rahul Rawat Virendra Yadav Wageesh Mishra Dorje Angchuk Anand Kumar Singh Low-latitude Auroras: Insights from 2023 April 23 Solar Storm The Astrophysical Journal Aurorae Solar particle emission Solar storm Solar coronal mass ejections |
| title | Low-latitude Auroras: Insights from 2023 April 23 Solar Storm |
| title_full | Low-latitude Auroras: Insights from 2023 April 23 Solar Storm |
| title_fullStr | Low-latitude Auroras: Insights from 2023 April 23 Solar Storm |
| title_full_unstemmed | Low-latitude Auroras: Insights from 2023 April 23 Solar Storm |
| title_short | Low-latitude Auroras: Insights from 2023 April 23 Solar Storm |
| title_sort | low latitude auroras insights from 2023 april 23 solar storm |
| topic | Aurorae Solar particle emission Solar storm Solar coronal mass ejections |
| url | https://doi.org/10.3847/1538-4357/ad8dd3 |
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