An Empirical Model of the Equatorial Electron Pitch Angle Distributions in Earth's Outer Radiation Belt
Abstract In this study, we present an empirical model of the equatorial electron pitch angle distributions (PADs) in the outer radiation belt based on the full data set collected by the Magnetic Electron Ion Spectrometer (MagEIS) instrument onboard the Van Allen Probes in 2012–2019. The PADs are fit...
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| Format: | Article |
| Language: | English |
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Wiley
2022-09-01
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| Series: | Space Weather |
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| Online Access: | https://doi.org/10.1029/2022SW003053 |
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| author | Artem Smirnov Yuri Y. Shprits Hayley Allison Nikita Aseev Alexander Drozdov Peter Kollmann Dedong Wang Anthony Saikin |
| author_facet | Artem Smirnov Yuri Y. Shprits Hayley Allison Nikita Aseev Alexander Drozdov Peter Kollmann Dedong Wang Anthony Saikin |
| author_sort | Artem Smirnov |
| collection | DOAJ |
| description | Abstract In this study, we present an empirical model of the equatorial electron pitch angle distributions (PADs) in the outer radiation belt based on the full data set collected by the Magnetic Electron Ion Spectrometer (MagEIS) instrument onboard the Van Allen Probes in 2012–2019. The PADs are fitted with a combination of the first, third and fifth sine harmonics. The resulting equation resolves all PAD types found in the outer radiation belt (pancake, flat‐top, butterfly and cap PADs) and can be analytically integrated to derive omnidirectional flux. We introduce a two‐step modeling procedure that for the first time ensures a continuous dependence on L, magnetic local time and activity, parametrized by the solar wind dynamic pressure. We propose two methods to reconstruct equatorial electron flux using the model. The first approach requires two uni‐directional flux observations and is applicable to low‐PA data. The second method can be used to reconstruct the full equatorial PADs from a single uni‐ or omnidirectional measurement at off‐equatorial latitudes. The model can be used for converting the long‐term data sets of electron fluxes to phase space density in terms of adiabatic invariants, for physics‐based modeling in the form of boundary conditions, and for data assimilation purposes. |
| format | Article |
| id | doaj-art-dd99455f92e54a77be1a572dac6c062e |
| institution | Kabale University |
| issn | 1542-7390 |
| language | English |
| publishDate | 2022-09-01 |
| publisher | Wiley |
| record_format | Article |
| series | Space Weather |
| spelling | doaj-art-dd99455f92e54a77be1a572dac6c062e2025-01-14T16:31:13ZengWileySpace Weather1542-73902022-09-01209n/an/a10.1029/2022SW003053An Empirical Model of the Equatorial Electron Pitch Angle Distributions in Earth's Outer Radiation BeltArtem Smirnov0Yuri Y. Shprits1Hayley Allison2Nikita Aseev3Alexander Drozdov4Peter Kollmann5Dedong Wang6Anthony Saikin7Helmholtz Centre Potsdam GFZ German Research Centre for Geosciences Potsdam GermanyHelmholtz Centre Potsdam GFZ German Research Centre for Geosciences Potsdam GermanyHelmholtz Centre Potsdam GFZ German Research Centre for Geosciences Potsdam GermanyHelmholtz Centre Potsdam GFZ German Research Centre for Geosciences Potsdam GermanyDepartment of Earth, Planetary and Space Sciences University of California Los Angeles CA USAApplied Physics Laboratory Johns Hopkins University Laurel MD USAHelmholtz Centre Potsdam GFZ German Research Centre for Geosciences Potsdam GermanyDepartment of Earth, Planetary and Space Sciences University of California Los Angeles CA USAAbstract In this study, we present an empirical model of the equatorial electron pitch angle distributions (PADs) in the outer radiation belt based on the full data set collected by the Magnetic Electron Ion Spectrometer (MagEIS) instrument onboard the Van Allen Probes in 2012–2019. The PADs are fitted with a combination of the first, third and fifth sine harmonics. The resulting equation resolves all PAD types found in the outer radiation belt (pancake, flat‐top, butterfly and cap PADs) and can be analytically integrated to derive omnidirectional flux. We introduce a two‐step modeling procedure that for the first time ensures a continuous dependence on L, magnetic local time and activity, parametrized by the solar wind dynamic pressure. We propose two methods to reconstruct equatorial electron flux using the model. The first approach requires two uni‐directional flux observations and is applicable to low‐PA data. The second method can be used to reconstruct the full equatorial PADs from a single uni‐ or omnidirectional measurement at off‐equatorial latitudes. The model can be used for converting the long‐term data sets of electron fluxes to phase space density in terms of adiabatic invariants, for physics‐based modeling in the form of boundary conditions, and for data assimilation purposes.https://doi.org/10.1029/2022SW003053pitch angleradiation beltmodelmagnetospherevan allen probeselectrons |
| spellingShingle | Artem Smirnov Yuri Y. Shprits Hayley Allison Nikita Aseev Alexander Drozdov Peter Kollmann Dedong Wang Anthony Saikin An Empirical Model of the Equatorial Electron Pitch Angle Distributions in Earth's Outer Radiation Belt Space Weather pitch angle radiation belt model magnetosphere van allen probes electrons |
| title | An Empirical Model of the Equatorial Electron Pitch Angle Distributions in Earth's Outer Radiation Belt |
| title_full | An Empirical Model of the Equatorial Electron Pitch Angle Distributions in Earth's Outer Radiation Belt |
| title_fullStr | An Empirical Model of the Equatorial Electron Pitch Angle Distributions in Earth's Outer Radiation Belt |
| title_full_unstemmed | An Empirical Model of the Equatorial Electron Pitch Angle Distributions in Earth's Outer Radiation Belt |
| title_short | An Empirical Model of the Equatorial Electron Pitch Angle Distributions in Earth's Outer Radiation Belt |
| title_sort | empirical model of the equatorial electron pitch angle distributions in earth s outer radiation belt |
| topic | pitch angle radiation belt model magnetosphere van allen probes electrons |
| url | https://doi.org/10.1029/2022SW003053 |
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