A Comparative Study of the Differential Deep Penetration of Energetic Electrons, Protons, and Heavy Ions Into the Low‐L Region
Abstract Energetic particle deep penetration into low L‐shells (L < 4) impacts the dynamics of the radiation belts and ring current. Previous studies reported that electrons penetrate more frequently, deeply, and faster than protons of similar energies, but underlying mechanisms are unclear. In t...
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| Format: | Article |
| Language: | English |
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Wiley
2025-07-01
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| Series: | Geophysical Research Letters |
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| Online Access: | https://doi.org/10.1029/2025GL116646 |
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| author | Rui Chen Hong Zhao Sam Califf Cristian Ferradas Mei‐Ching Fok |
| author_facet | Rui Chen Hong Zhao Sam Califf Cristian Ferradas Mei‐Ching Fok |
| author_sort | Rui Chen |
| collection | DOAJ |
| description | Abstract Energetic particle deep penetration into low L‐shells (L < 4) impacts the dynamics of the radiation belts and ring current. Previous studies reported that electrons penetrate more frequently, deeply, and faster than protons of similar energies, but underlying mechanisms are unclear. In this study, we compare heavy‐ion behavior with electrons and protons to further identify the underlying mechanisms. Using Van Allen Probes data, we show that electron deep penetration occurs most frequently and deeply, followed by O+ ions, then He+ ions, and finally protons. Most particle deep penetrations occur within several hours. Superposed epoch analysis shows that prior to deep penetration, electrons have the steepest phase space density radial gradients, followed by heavy ions and then protons for the same μ and K. Our study suggests that a combination of two or more mechanisms, such as convection electric field and plasma wave‐induced scattering, may be needed to fully explain particle deep penetration. |
| format | Article |
| id | doaj-art-33b7ba7278aa4c5f80423726233933d3 |
| institution | Kabale University |
| issn | 0094-8276 1944-8007 |
| language | English |
| publishDate | 2025-07-01 |
| publisher | Wiley |
| record_format | Article |
| series | Geophysical Research Letters |
| spelling | doaj-art-33b7ba7278aa4c5f80423726233933d32025-08-20T03:58:44ZengWileyGeophysical Research Letters0094-82761944-80072025-07-015214n/an/a10.1029/2025GL116646A Comparative Study of the Differential Deep Penetration of Energetic Electrons, Protons, and Heavy Ions Into the Low‐L RegionRui Chen0Hong Zhao1Sam Califf2Cristian Ferradas3Mei‐Ching Fok4Department of Physics Auburn University Auburn AL USADepartment of Physics Auburn University Auburn AL USACIRES University of Colorado Boulder Boulder CO USANASA Goddard Space Flight Center Geospace Physics Laboratory Greenbelt MD USANASA Goddard Space Flight Center Geospace Physics Laboratory Greenbelt MD USAAbstract Energetic particle deep penetration into low L‐shells (L < 4) impacts the dynamics of the radiation belts and ring current. Previous studies reported that electrons penetrate more frequently, deeply, and faster than protons of similar energies, but underlying mechanisms are unclear. In this study, we compare heavy‐ion behavior with electrons and protons to further identify the underlying mechanisms. Using Van Allen Probes data, we show that electron deep penetration occurs most frequently and deeply, followed by O+ ions, then He+ ions, and finally protons. Most particle deep penetrations occur within several hours. Superposed epoch analysis shows that prior to deep penetration, electrons have the steepest phase space density radial gradients, followed by heavy ions and then protons for the same μ and K. Our study suggests that a combination of two or more mechanisms, such as convection electric field and plasma wave‐induced scattering, may be needed to fully explain particle deep penetration.https://doi.org/10.1029/2025GL116646particle deep penetrationradiation beltsring currentplasma convection |
| spellingShingle | Rui Chen Hong Zhao Sam Califf Cristian Ferradas Mei‐Ching Fok A Comparative Study of the Differential Deep Penetration of Energetic Electrons, Protons, and Heavy Ions Into the Low‐L Region Geophysical Research Letters particle deep penetration radiation belts ring current plasma convection |
| title | A Comparative Study of the Differential Deep Penetration of Energetic Electrons, Protons, and Heavy Ions Into the Low‐L Region |
| title_full | A Comparative Study of the Differential Deep Penetration of Energetic Electrons, Protons, and Heavy Ions Into the Low‐L Region |
| title_fullStr | A Comparative Study of the Differential Deep Penetration of Energetic Electrons, Protons, and Heavy Ions Into the Low‐L Region |
| title_full_unstemmed | A Comparative Study of the Differential Deep Penetration of Energetic Electrons, Protons, and Heavy Ions Into the Low‐L Region |
| title_short | A Comparative Study of the Differential Deep Penetration of Energetic Electrons, Protons, and Heavy Ions Into the Low‐L Region |
| title_sort | comparative study of the differential deep penetration of energetic electrons protons and heavy ions into the low l region |
| topic | particle deep penetration radiation belts ring current plasma convection |
| url | https://doi.org/10.1029/2025GL116646 |
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