Space weather with an arc’s ∼2 h trip across the nightside polar cap
Flow channels can extend across the polar cap from the dayside to the nightside auroral oval, where they lead to localized reconnection and auroral oval disturbances. Such flow channels can persist within the polar cap >1½ hours, can move azimuthally with direction controlled by IMF By, and m...
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| Format: | Article |
| Language: | English |
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Frontiers Media S.A.
2024-01-01
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| Series: | Frontiers in Astronomy and Space Sciences |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/fspas.2023.1309870/full |
| _version_ | 1797349433349767168 |
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| author | Larry R. Lyons Yukitoshi Nishimura Jiang Liu Jiang Liu Sneha Yadav Ying Zou William A. Bristow Eric Donovan Nozomu Nishitani |
| author_facet | Larry R. Lyons Yukitoshi Nishimura Jiang Liu Jiang Liu Sneha Yadav Ying Zou William A. Bristow Eric Donovan Nozomu Nishitani |
| author_sort | Larry R. Lyons |
| collection | DOAJ |
| description | Flow channels can extend across the polar cap from the dayside to the nightside auroral oval, where they lead to localized reconnection and auroral oval disturbances. Such flow channels can persist within the polar cap >1½ hours, can move azimuthally with direction controlled by IMF By, and may affect time and location of auroral oval disturbances. We have followed a polar cap arc as it moved duskward from Canada to Alaska for ∼2 h while connected to the oval. Two-dimensional ionospheric flows show an adjacent flow channel that moved westward with the arc and was a distinct feature of polar cap convection that locally impinged upon the outer boundary of the auroral oval. The flow channel’s interaction with the oval appears to have triggered two separate substorms during its trip across western Canada and Alaska, controlling the onset location and contributing to subsequent development of substorm activity within the oval. The first substorm (over Canada) occurred during approximately equatorward polar cap flow, whereas the second substorm (over Alaska) occurred as the polar cap arc and flow channel bent strongly azimuthally and appeared to “lay down” along the poleward boundary. The oval became unusually thin, leading to near contact between the polar cap arc and the brightening onset auroral arc within the oval. These observations illustrate the crucial role of polar cap flow channels in the time, location, and duration of space weather activity, and the importance of the duration and azimuthal motion of flow channels within the nightside polar cap. |
| first_indexed | 2024-03-08T12:30:10Z |
| format | Article |
| id | doaj.art-610649d188da479bb20d1a3d089f0b34 |
| institution | Directory Open Access Journal |
| issn | 2296-987X |
| language | English |
| last_indexed | 2024-03-08T12:30:10Z |
| publishDate | 2024-01-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Astronomy and Space Sciences |
| spelling | doaj.art-610649d188da479bb20d1a3d089f0b342024-01-22T04:21:47ZengFrontiers Media S.A.Frontiers in Astronomy and Space Sciences2296-987X2024-01-011010.3389/fspas.2023.13098701309870Space weather with an arc’s ∼2 h trip across the nightside polar capLarry R. Lyons0Yukitoshi Nishimura1Jiang Liu2Jiang Liu3Sneha Yadav4Ying Zou5William A. Bristow6Eric Donovan7Nozomu Nishitani8Department of Atmospheric and Oceanic Sciences, University of California, Los Angeles, Los Angeles, CA, United StatesCenter for Space Physics, Department of Electrical and Computer Engineering, Boston University, Boston, MA, United StatesDepartment of Atmospheric and Oceanic Sciences, University of California, Los Angeles, Los Angeles, CA, United StatesDepartment of Earth, Planetary, and Space Sciences, University of California, Los Angeles, Los Angeles, CA, United StatesDepartment of Atmospheric and Oceanic Sciences, University of California, Los Angeles, Los Angeles, CA, United StatesApplied Physics Laboratory, Laurel, MD, United StatesDepartment of Meteorology and Atmospheric Science, The Pennsylvania State University, State College, PA, United StatesDepartment of Physics and Astronomy, University of Calgary, Calgary, AB, CanadaInstitute for Space-Earth Environmental Research, Nagoya University, Nagoya, Aichi, JapanFlow channels can extend across the polar cap from the dayside to the nightside auroral oval, where they lead to localized reconnection and auroral oval disturbances. Such flow channels can persist within the polar cap >1½ hours, can move azimuthally with direction controlled by IMF By, and may affect time and location of auroral oval disturbances. We have followed a polar cap arc as it moved duskward from Canada to Alaska for ∼2 h while connected to the oval. Two-dimensional ionospheric flows show an adjacent flow channel that moved westward with the arc and was a distinct feature of polar cap convection that locally impinged upon the outer boundary of the auroral oval. The flow channel’s interaction with the oval appears to have triggered two separate substorms during its trip across western Canada and Alaska, controlling the onset location and contributing to subsequent development of substorm activity within the oval. The first substorm (over Canada) occurred during approximately equatorward polar cap flow, whereas the second substorm (over Alaska) occurred as the polar cap arc and flow channel bent strongly azimuthally and appeared to “lay down” along the poleward boundary. The oval became unusually thin, leading to near contact between the polar cap arc and the brightening onset auroral arc within the oval. These observations illustrate the crucial role of polar cap flow channels in the time, location, and duration of space weather activity, and the importance of the duration and azimuthal motion of flow channels within the nightside polar cap.https://www.frontiersin.org/articles/10.3389/fspas.2023.1309870/fullpolar capauroraconvectionflow channelsspace weathersubstorms |
| spellingShingle | Larry R. Lyons Yukitoshi Nishimura Jiang Liu Jiang Liu Sneha Yadav Ying Zou William A. Bristow Eric Donovan Nozomu Nishitani Space weather with an arc’s ∼2 h trip across the nightside polar cap Frontiers in Astronomy and Space Sciences polar cap aurora convection flow channels space weather substorms |
| title | Space weather with an arc’s ∼2 h trip across the nightside polar cap |
| title_full | Space weather with an arc’s ∼2 h trip across the nightside polar cap |
| title_fullStr | Space weather with an arc’s ∼2 h trip across the nightside polar cap |
| title_full_unstemmed | Space weather with an arc’s ∼2 h trip across the nightside polar cap |
| title_short | Space weather with an arc’s ∼2 h trip across the nightside polar cap |
| title_sort | space weather with an arc s ∼2 h trip across the nightside polar cap |
| topic | polar cap aurora convection flow channels space weather substorms |
| url | https://www.frontiersin.org/articles/10.3389/fspas.2023.1309870/full |
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