Modeling the Electron Flux Enhancement and Butterfly Pitch Angle Distributions on L Shells <2.5
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Abstract |
We analyze an energetic electron flux enhancement event in the inner radiation belt observed by Van Allen Probes during an intense geomagnetic storm. The energetic electron flux at L~1.5 increased by a factor of 3 with pronounced butterfly pitch angle distributions (PADs). Using a three-dimensional radiation belt model, we simulate the electron evolution under the impact of radial diffusion, local wave-particle interactions including hiss, very low frequency transmitters, and magnetosonic waves, as well as Coulomb scattering. Consistency between observation and simulation suggests that inward radial diffusion plays a dominant role in accelerating electrons up to 900 keV and transporting the butterfly PADs from higher L shells to form the butterfly PADs at L~1.5. However, local wave-particle interactions also contribute to drive butterfly PADs at L ≳ 1.9. Our study provides a feasible mechanism to explain the electron flux enhancement in the inner belt and the persistent presence of the butterfly PADs at L~1.5.
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Year of Publication |
2019
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Journal |
Geophysical Research Letters
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Volume |
46
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Number of Pages |
10967-10976
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Date Published |
09/2019
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ISSN Number |
0094-8276
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URL |
https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2019GL084822
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DOI |
10.1029/2019GL084822
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