A new auroral phenomenon, the anti-black aurora
Black auroras are small-scale features embedded in the diffuse background aurora, typically occurring post-substorm after magnetic midnight and with an eastward drift imposed. Black auroras show a significant reduction in optical brightness compared to the surrounding diffuse aurora, and can appear...
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Online Access: | http://hdl.handle.net/10566/6031 https://doi.org/10.1038/s41598-021-81363-9 |
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ftunivwesterncrr:oai:repository.uwc.ac.za:10566/6031 2023-05-15T18:34:40+02:00 A new auroral phenomenon, the anti-black aurora Nel, A.E. Kosch, M.J. Whiter, D. Gustavsson, B. Aslaksen, T. 2021 application/pdf http://hdl.handle.net/10566/6031 https://doi.org/10.1038/s41598-021-81363-9 en eng Nature Nel, A.E., Kosch, M.J., Whiter, D. et al. (2021) A new auroral phenomenon, the anti-black aurora. Sci Rep 11, 1829. https://doi.org/10.1038/s41598-021-81363-9 2045-2322 https://doi.org/10.1038/s41598-021-81363-9 http://hdl.handle.net/10566/6031 Luminance Norway Anti-black aurora Electron Velocity Article 2021 ftunivwesterncrr https://doi.org/10.1038/s41598-021-81363-9 2022-04-26T18:57:43Z Black auroras are small-scale features embedded in the diffuse background aurora, typically occurring post-substorm after magnetic midnight and with an eastward drift imposed. Black auroras show a significant reduction in optical brightness compared to the surrounding diffuse aurora, and can appear as slow-moving arcs or rapidly-moving patches and arc segments. We report, for the first time, an even more elusive small-scale optical structure that has always been observed occurring paired with ∼ 10% of black aurora patches. A patch or arc segment of enhanced luminosity, distinctly brighter than the diffuse background, which we name the anti-black aurora, may appear adjacent to the black aurora. The anti-black aurora is of similar shape and size, and always moves in parallel to the drifting black aurora, although it may suddenly switch sides for no apparent reason. The paired phenomenon always drifts with the same average speed in an easterly direction. From the first dual-wavelength (427.8 nm and 844.6 nm) optical observations of the phenomenon recorded on 12 March 2016 outside Tromsø Norway, we show that the anti-black and black auroras have a higher and lower mean energy, respectively, of the precipitating electrons compared to the diffuse background. Article in Journal/Newspaper Tromsø University of the Western Cap: UWC Research Repository Norway Tromsø Scientific Reports 5 1 |
institution |
Open Polar |
collection |
University of the Western Cap: UWC Research Repository |
op_collection_id |
ftunivwesterncrr |
language |
English |
topic |
Luminance Norway Anti-black aurora Electron Velocity |
spellingShingle |
Luminance Norway Anti-black aurora Electron Velocity Nel, A.E. Kosch, M.J. Whiter, D. Gustavsson, B. Aslaksen, T. A new auroral phenomenon, the anti-black aurora |
topic_facet |
Luminance Norway Anti-black aurora Electron Velocity |
description |
Black auroras are small-scale features embedded in the diffuse background aurora, typically occurring post-substorm after magnetic midnight and with an eastward drift imposed. Black auroras show a significant reduction in optical brightness compared to the surrounding diffuse aurora, and can appear as slow-moving arcs or rapidly-moving patches and arc segments. We report, for the first time, an even more elusive small-scale optical structure that has always been observed occurring paired with ∼ 10% of black aurora patches. A patch or arc segment of enhanced luminosity, distinctly brighter than the diffuse background, which we name the anti-black aurora, may appear adjacent to the black aurora. The anti-black aurora is of similar shape and size, and always moves in parallel to the drifting black aurora, although it may suddenly switch sides for no apparent reason. The paired phenomenon always drifts with the same average speed in an easterly direction. From the first dual-wavelength (427.8 nm and 844.6 nm) optical observations of the phenomenon recorded on 12 March 2016 outside Tromsø Norway, we show that the anti-black and black auroras have a higher and lower mean energy, respectively, of the precipitating electrons compared to the diffuse background. |
format |
Article in Journal/Newspaper |
author |
Nel, A.E. Kosch, M.J. Whiter, D. Gustavsson, B. Aslaksen, T. |
author_facet |
Nel, A.E. Kosch, M.J. Whiter, D. Gustavsson, B. Aslaksen, T. |
author_sort |
Nel, A.E. |
title |
A new auroral phenomenon, the anti-black aurora |
title_short |
A new auroral phenomenon, the anti-black aurora |
title_full |
A new auroral phenomenon, the anti-black aurora |
title_fullStr |
A new auroral phenomenon, the anti-black aurora |
title_full_unstemmed |
A new auroral phenomenon, the anti-black aurora |
title_sort |
new auroral phenomenon, the anti-black aurora |
publisher |
Nature |
publishDate |
2021 |
url |
http://hdl.handle.net/10566/6031 https://doi.org/10.1038/s41598-021-81363-9 |
geographic |
Norway Tromsø |
geographic_facet |
Norway Tromsø |
genre |
Tromsø |
genre_facet |
Tromsø |
op_relation |
Nel, A.E., Kosch, M.J., Whiter, D. et al. (2021) A new auroral phenomenon, the anti-black aurora. Sci Rep 11, 1829. https://doi.org/10.1038/s41598-021-81363-9 2045-2322 https://doi.org/10.1038/s41598-021-81363-9 http://hdl.handle.net/10566/6031 |
op_doi |
https://doi.org/10.1038/s41598-021-81363-9 |
container_title |
Scientific Reports |
container_volume |
5 |
container_issue |
1 |
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1766219516756361216 |