Observations of kinetic Alfvén waves and associated electron acceleration in the plasma sheet boundary layer
Kinetic Alfvén waves (KAWs), with a strong parallel disturbed electric field, play an important role in energy transport and particle acceleration in the magnetotail. On the basis of high-resolution observations of the Magnetospheric Multiscale (MMS) Mission, we present a detailed description of the...
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| Format: | Article |
| Language: | English |
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Science Press
2022-08-01
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| Series: | Earth and Planetary Physics |
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| Online Access: | http://www.eppcgs.org/article/doi/10.26464/epp2022041?pageType=en |
| _version_ | 1811262101866414080 |
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| author | ZeHao Zhang ZhiGang Yuan ShiYong Huang XiongDong Yu ZuXiang Xue Dan Deng Zheng Huang |
| author_facet | ZeHao Zhang ZhiGang Yuan ShiYong Huang XiongDong Yu ZuXiang Xue Dan Deng Zheng Huang |
| author_sort | ZeHao Zhang |
| collection | DOAJ |
| description | Kinetic Alfvén waves (KAWs), with a strong parallel disturbed electric field, play an important role in energy transport and particle acceleration in the magnetotail. On the basis of high-resolution observations of the Magnetospheric Multiscale (MMS) Mission, we present a detailed description of the acceleration process of electrons by KAWs in the plasma sheet boundary layer (PSBL). The MMS observed strong electromagnetic disturbances carrying a parallel disturbed electric field with an amplitude of up to 8 mV/m. The measured ratio of the electric to magnetic field perturbations was larger than the local Alfvén speed and was enhanced as the frequency increased, consistent with the theoretical predictions for KAWs. This evidence indicates that the electromagnetic disturbances should be identified as KAWs. During the KAWs, the energy flux of electrons at energies above 1 keV in the parallel and anti-parallel directions are significantly enhanced, implying occurrences of electron beams at higher energies. Additionally, the KAWs became more electrostatic-like and filled with high-frequency ion acoustic waves. The energy enhancement of electron beams is in accordance with the derived work done with the observed parallel disturbed electric field of KAWs, indicating electron acceleration caused by KAWs. Therefore, these results provide direct evidence of electron acceleration by KAWs embodying electrostatic ion acoustic waves in the PSBL. |
| first_indexed | 2024-04-12T19:19:22Z |
| format | Article |
| id | doaj.art-4c0ade9812be475a9f6212316a8c88b9 |
| institution | Directory Open Access Journal |
| issn | 2096-3955 |
| language | English |
| last_indexed | 2024-04-12T19:19:22Z |
| publishDate | 2022-08-01 |
| publisher | Science Press |
| record_format | Article |
| series | Earth and Planetary Physics |
| spelling | doaj.art-4c0ade9812be475a9f6212316a8c88b92022-12-22T03:19:39ZengScience PressEarth and Planetary Physics2096-39552022-08-016546547310.26464/epp2022041RA330-zhangzehao-FObservations of kinetic Alfvén waves and associated electron acceleration in the plasma sheet boundary layerZeHao Zhang0ZhiGang Yuan1ShiYong Huang2XiongDong Yu3ZuXiang Xue4Dan Deng5Zheng Huang6School of Electronic Information, Wuhan University, Wuhan 430072, ChinaSchool of Electronic Information, Wuhan University, Wuhan 430072, ChinaSchool of Electronic Information, Wuhan University, Wuhan 430072, ChinaSchool of Electronic Information, Wuhan University, Wuhan 430072, ChinaSchool of Electronic Information, Wuhan University, Wuhan 430072, ChinaSchool of Electronic Information, Wuhan University, Wuhan 430072, ChinaSchool of Electronic Information, Wuhan University, Wuhan 430072, ChinaKinetic Alfvén waves (KAWs), with a strong parallel disturbed electric field, play an important role in energy transport and particle acceleration in the magnetotail. On the basis of high-resolution observations of the Magnetospheric Multiscale (MMS) Mission, we present a detailed description of the acceleration process of electrons by KAWs in the plasma sheet boundary layer (PSBL). The MMS observed strong electromagnetic disturbances carrying a parallel disturbed electric field with an amplitude of up to 8 mV/m. The measured ratio of the electric to magnetic field perturbations was larger than the local Alfvén speed and was enhanced as the frequency increased, consistent with the theoretical predictions for KAWs. This evidence indicates that the electromagnetic disturbances should be identified as KAWs. During the KAWs, the energy flux of electrons at energies above 1 keV in the parallel and anti-parallel directions are significantly enhanced, implying occurrences of electron beams at higher energies. Additionally, the KAWs became more electrostatic-like and filled with high-frequency ion acoustic waves. The energy enhancement of electron beams is in accordance with the derived work done with the observed parallel disturbed electric field of KAWs, indicating electron acceleration caused by KAWs. Therefore, these results provide direct evidence of electron acceleration by KAWs embodying electrostatic ion acoustic waves in the PSBL.http://www.eppcgs.org/article/doi/10.26464/epp2022041?pageType=enkinetic alfvén waveplasma sheet boundary layerelectron energizationpoynting flux |
| spellingShingle | ZeHao Zhang ZhiGang Yuan ShiYong Huang XiongDong Yu ZuXiang Xue Dan Deng Zheng Huang Observations of kinetic Alfvén waves and associated electron acceleration in the plasma sheet boundary layer Earth and Planetary Physics kinetic alfvén wave plasma sheet boundary layer electron energization poynting flux |
| title | Observations of kinetic Alfvén waves and associated electron acceleration in the plasma sheet boundary layer |
| title_full | Observations of kinetic Alfvén waves and associated electron acceleration in the plasma sheet boundary layer |
| title_fullStr | Observations of kinetic Alfvén waves and associated electron acceleration in the plasma sheet boundary layer |
| title_full_unstemmed | Observations of kinetic Alfvén waves and associated electron acceleration in the plasma sheet boundary layer |
| title_short | Observations of kinetic Alfvén waves and associated electron acceleration in the plasma sheet boundary layer |
| title_sort | observations of kinetic alfven waves and associated electron acceleration in the plasma sheet boundary layer |
| topic | kinetic alfvén wave plasma sheet boundary layer electron energization poynting flux |
| url | http://www.eppcgs.org/article/doi/10.26464/epp2022041?pageType=en |
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