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- Title
Modeling the Simultaneous Dropout of Energetic Electrons and Protons by Magnetopause Shadowing.
- Authors
Lyu, Xingzhi; Tu, Weichao; Huang, Jinbei; Ma, Qianli; Li, Zhi‐Gu
- Abstract
Magnetopause shadowing (MPS) effect could drive a concurrent dropout of radiation belt electrons and ring current protons. However, its relative role in the dropout of both plasma populations has not been well quantified. In this work, we study the simultaneous dropout of MeV electrons and 100s keV protons during an intense geomagnetic storm in May 2017. A radial diffusion model with an event‐specific last closed drift shell is used to simulate the MPS loss of both populations. The model well captures the fast shadowing loss of both populations at L* > 4.6, while the loss at L* < 4.6, possibly due to the electromagnetic ion cyclotron wave scattering, is not captured. The observed butterfly pitch angle distributions of electron fluxes in the initial loss phase are well reproduced by the model. The initial proton losses at low pitch angles are underestimated, potentially also contributed by other mechanisms such as field line curvature scattering. Plain Language Summary: Magnetopause shadowing, due to the solar wind compression of the magnetopause combined with outward radial diffusion driven by ultra low frequency waves, is known to be one of the major loss mechanisms for both radiation belt electrons and ring current protons. However, the role of MPS in driving the simultaneous dropout of both populations has not been well quantified. In this study, for the first time, we quantitatively model the fast shadowing loss of radiation belt electrons and ring current protons during a geomagnetic storm event using a radial diffusion model with event‐specific inputs. The results indicate that MPS can efficiently capture the concurrent fast depletion of both populations at high L*. Key Points: A radial diffusion model with event‐specific last closed drift shell is used to simulate the concurrent dropout of electrons and protons due to magnetopause shadowingThe model captures the fast shadowing loss of both populations at high L* but not the loss at low L* possibly from electromagnetic ion cyclotron wave scatteringThe model reproduces the butterfly PAD of electrons in the initial loss phase but underestimates the loss of protons at low pitch angles
- Subjects
MAGNETOPAUSE; PROTONS; ELECTRON distribution; ELECTRON diffusion; ELECTRONS; RADIATION belts
- Publication
Geophysical Research Letters, 2024, Vol 51, Issue 2, p1
- ISSN
0094-8276
- Publication type
Article
- DOI
10.1029/2023GL106681