Upper Limit of Outer Radiation Belt Electron Acceleration Driven by Whistler‐Mode Chorus Waves
Abstract We investigate the outer radiation belt electron energy spectra of the highest fluxes observed during storms based on Van Allen Probes measurements, which demonstrate a similar shape despite various levels of geomagnetic activity. Using quasi‐linear diffusion simulations, we reproduce the o...
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Wiley
2022-08-01
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| Series: | Geophysical Research Letters |
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| Online Access: | https://doi.org/10.1029/2022GL099618 |
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| author | Man Hua Jacob Bortnik Qianli Ma |
| author_facet | Man Hua Jacob Bortnik Qianli Ma |
| author_sort | Man Hua |
| collection | DOAJ |
| description | Abstract We investigate the outer radiation belt electron energy spectra of the highest fluxes observed during storms based on Van Allen Probes measurements, which demonstrate a similar shape despite various levels of geomagnetic activity. Using quasi‐linear diffusion simulations, we reproduce the observed electron acceleration by whistler‐mode chorus waves during the storm of 25 October 2016, when the maximum fluxes were close to the highest upper limit observed during the 2013–2018 period. The electrons below ∼1 MeV reached the upper limit of chorus acceleration within ∼1 day and then remained at a stable level, while the multi‐MeV electrons with sharper energy gradient were subject to the continuous acceleration process. Our results reveal the natural upper limit of electron acceleration by chorus, which strongly depends on the lower energy boundary, and the stable seed population at hundreds of keV (but not the chorus intensity) which is a prerequisite for the relativistic electron acceleration. |
| format | Article |
| id | doaj-art-b9f33e6e5b664f4ca64ad511e87be09e |
| institution | OA Journals |
| issn | 0094-8276 1944-8007 |
| language | English |
| publishDate | 2022-08-01 |
| publisher | Wiley |
| record_format | Article |
| series | Geophysical Research Letters |
| spelling | doaj-art-b9f33e6e5b664f4ca64ad511e87be09e2025-08-20T02:27:43ZengWileyGeophysical Research Letters0094-82761944-80072022-08-014915n/an/a10.1029/2022GL099618Upper Limit of Outer Radiation Belt Electron Acceleration Driven by Whistler‐Mode Chorus WavesMan Hua0Jacob Bortnik1Qianli Ma2Department of Atmospheric and Oceanic Sciences UCLA Los Angeles CA USADepartment of Atmospheric and Oceanic Sciences UCLA Los Angeles CA USADepartment of Atmospheric and Oceanic Sciences UCLA Los Angeles CA USAAbstract We investigate the outer radiation belt electron energy spectra of the highest fluxes observed during storms based on Van Allen Probes measurements, which demonstrate a similar shape despite various levels of geomagnetic activity. Using quasi‐linear diffusion simulations, we reproduce the observed electron acceleration by whistler‐mode chorus waves during the storm of 25 October 2016, when the maximum fluxes were close to the highest upper limit observed during the 2013–2018 period. The electrons below ∼1 MeV reached the upper limit of chorus acceleration within ∼1 day and then remained at a stable level, while the multi‐MeV electrons with sharper energy gradient were subject to the continuous acceleration process. Our results reveal the natural upper limit of electron acceleration by chorus, which strongly depends on the lower energy boundary, and the stable seed population at hundreds of keV (but not the chorus intensity) which is a prerequisite for the relativistic electron acceleration.https://doi.org/10.1029/2022GL099618radiation belt electron accelerationwhistler‐mode chorus wavesquasi‐linear diffusion simulationwave‐particle interactions |
| spellingShingle | Man Hua Jacob Bortnik Qianli Ma Upper Limit of Outer Radiation Belt Electron Acceleration Driven by Whistler‐Mode Chorus Waves Geophysical Research Letters radiation belt electron acceleration whistler‐mode chorus waves quasi‐linear diffusion simulation wave‐particle interactions |
| title | Upper Limit of Outer Radiation Belt Electron Acceleration Driven by Whistler‐Mode Chorus Waves |
| title_full | Upper Limit of Outer Radiation Belt Electron Acceleration Driven by Whistler‐Mode Chorus Waves |
| title_fullStr | Upper Limit of Outer Radiation Belt Electron Acceleration Driven by Whistler‐Mode Chorus Waves |
| title_full_unstemmed | Upper Limit of Outer Radiation Belt Electron Acceleration Driven by Whistler‐Mode Chorus Waves |
| title_short | Upper Limit of Outer Radiation Belt Electron Acceleration Driven by Whistler‐Mode Chorus Waves |
| title_sort | upper limit of outer radiation belt electron acceleration driven by whistler mode chorus waves |
| topic | radiation belt electron acceleration whistler‐mode chorus waves quasi‐linear diffusion simulation wave‐particle interactions |
| url | https://doi.org/10.1029/2022GL099618 |
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