An empirical model of the equatorial electron pitch angle distributions in earth's outer radiation belt
- 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 atIn 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.…
Author details: | Artem SmirnovORCiDGND, Yuri ShpritsORCiDGND, Hayley AllisonORCiD, Nikita AseevORCiDGND, Alexander DrozdovORCiDGND, Peter KollmannORCiDGND, Dedong WangORCiDGND, Anthony SaikinORCiD |
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DOI: | https://doi.org/10.1029/2022SW003053 |
ISSN: | 1542-7390 |
Title of parent work (English): | Space Weather: the International Journal of Research and Applications |
Publisher: | American Geophysical Union |
Place of publishing: | Washington, DC |
Publication type: | Article |
Language: | English |
Date of first publication: | 2022/06/24 |
Publication year: | 2022 |
Release date: | 2023/11/10 |
Tag: | electrons; magnetosphere; model; pitch angle; radiation belt; van allen probes; |
Volume: | 20 |
Issue: | 9 |
Article number: | e2022SW003053 |
Number of pages: | 17 |
Funding institution: | Deutsche Forschungsgemeinschaft, Germany [SFB 1294, 318763901];; International Space Science Institute (ISSI-Bern, Switzerland);; Alexander von Humboldt foundation; Projekt DEAL |
Organizational units: | Mathematisch-Naturwissenschaftliche Fakultät / Institut für Physik und Astronomie |
DDC classification: | 5 Naturwissenschaften und Mathematik / 53 Physik / 530 Physik |
Peer review: | Referiert |
Publishing method: | Open Access / Hybrid Open-Access |
License (German): | CC-BY-NC - Namensnennung, nicht kommerziell 4.0 International |