Relation between magnetosonic waves and pitch angle anisotropy of warm protons
In the past decade, many observations of transversely heated low energy protons were reported in the inner magnetosphere. Interestingly, most of the time heated protons were observed along with magnetosonic waves. Due to the strong correlation, it was often assumed that magnetosonic waves were respo...
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| Format: | Article |
| Language: | English |
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Frontiers Media S.A.
2022-11-01
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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.2022.1035563/full |
| _version_ | 1811189850756349952 |
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| author | J. Joseph A. N. Jaynes Q. Ma Q. Ma D. P. Hartley M. E. Usanova W. Li |
| author_facet | J. Joseph A. N. Jaynes Q. Ma Q. Ma D. P. Hartley M. E. Usanova W. Li |
| author_sort | J. Joseph |
| collection | DOAJ |
| description | In the past decade, many observations of transversely heated low energy protons were reported in the inner magnetosphere. Interestingly, most of the time heated protons were observed along with magnetosonic waves. Due to the strong correlation, it was often assumed that magnetosonic waves were responsible for the heating of low energy protons. By performing a case study under unusually disturbed geomagnetic conditions, this paper unravels the controversial relationship between the observed pitch angle anisotropy of warm protons and the accompanying magnetosonic waves in the inner magnetosphere. We perform a comparative analysis involving two nearly identical cases of pitch angle anisotropy of warm protons in low L-shell region–one with magnetosonic waves and one without them. It is found that magnetosonic waves are not responsible for primary heating of low-energy protons and may just marginally alter the shape of the distribution of heated protons in the events analyzed. Based on the recent Cluster and POLAR observations, we also show how the recirculated polar wind plasma in the Earth’s magnetosphere can cause the concurrent appearance of heated protons and magnetosonic waves. |
| first_indexed | 2024-04-11T14:41:46Z |
| format | Article |
| id | doaj.art-7b01ad220780479eb78b31628f6e0ff8 |
| institution | Directory Open Access Journal |
| issn | 2296-987X |
| language | English |
| last_indexed | 2024-04-11T14:41:46Z |
| publishDate | 2022-11-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Astronomy and Space Sciences |
| spelling | doaj.art-7b01ad220780479eb78b31628f6e0ff82022-12-22T04:17:54ZengFrontiers Media S.A.Frontiers in Astronomy and Space Sciences2296-987X2022-11-01910.3389/fspas.2022.10355631035563Relation between magnetosonic waves and pitch angle anisotropy of warm protonsJ. Joseph0A. N. Jaynes1Q. Ma2Q. Ma3D. P. Hartley4M. E. Usanova5W. Li6Department of Physics and Astronomy, University of Iowa, Iowa City, IA, United StatesDepartment of Physics and Astronomy, University of Iowa, Iowa City, IA, United StatesCenter for Space Physics, Boston University, Boston, MA, United StatesDepartment of Atmospheric and Oceanic Sciences, University of California, Los Angeles, Los Angeles, CA, United StatesDepartment of Physics and Astronomy, University of Iowa, Iowa City, IA, United StatesLaboratory for Atmospheric and Space Physics, University of Colorado Boulder, Boulder, CO, United StatesCenter for Space Physics, Boston University, Boston, MA, United StatesIn the past decade, many observations of transversely heated low energy protons were reported in the inner magnetosphere. Interestingly, most of the time heated protons were observed along with magnetosonic waves. Due to the strong correlation, it was often assumed that magnetosonic waves were responsible for the heating of low energy protons. By performing a case study under unusually disturbed geomagnetic conditions, this paper unravels the controversial relationship between the observed pitch angle anisotropy of warm protons and the accompanying magnetosonic waves in the inner magnetosphere. We perform a comparative analysis involving two nearly identical cases of pitch angle anisotropy of warm protons in low L-shell region–one with magnetosonic waves and one without them. It is found that magnetosonic waves are not responsible for primary heating of low-energy protons and may just marginally alter the shape of the distribution of heated protons in the events analyzed. Based on the recent Cluster and POLAR observations, we also show how the recirculated polar wind plasma in the Earth’s magnetosphere can cause the concurrent appearance of heated protons and magnetosonic waves.https://www.frontiersin.org/articles/10.3389/fspas.2022.1035563/fullmagnetosonic wavepitch angle anisotropywave-particle interactionpolar windquasi-linear analysis |
| spellingShingle | J. Joseph A. N. Jaynes Q. Ma Q. Ma D. P. Hartley M. E. Usanova W. Li Relation between magnetosonic waves and pitch angle anisotropy of warm protons Frontiers in Astronomy and Space Sciences magnetosonic wave pitch angle anisotropy wave-particle interaction polar wind quasi-linear analysis |
| title | Relation between magnetosonic waves and pitch angle anisotropy of warm protons |
| title_full | Relation between magnetosonic waves and pitch angle anisotropy of warm protons |
| title_fullStr | Relation between magnetosonic waves and pitch angle anisotropy of warm protons |
| title_full_unstemmed | Relation between magnetosonic waves and pitch angle anisotropy of warm protons |
| title_short | Relation between magnetosonic waves and pitch angle anisotropy of warm protons |
| title_sort | relation between magnetosonic waves and pitch angle anisotropy of warm protons |
| topic | magnetosonic wave pitch angle anisotropy wave-particle interaction polar wind quasi-linear analysis |
| url | https://www.frontiersin.org/articles/10.3389/fspas.2022.1035563/full |
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