Exploring the Magnetotail from Low Altitudes: Evolution of Energetic Electron Flux During the Substorm Growth Phase

Fuente: arXiv
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Autores principales: Sun, Weiqin, Zhang, Xiao-Jia, Artemyev, Anton V., Nakamura, Rumi, Yang, Jian, Angelopoulos, Vassilis
Formato: Preprint
Publicado: 2025
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author Sun, Weiqin
Zhang, Xiao-Jia
Artemyev, Anton V.
Nakamura, Rumi
Yang, Jian
Angelopoulos, Vassilis
author_facet Sun, Weiqin
Zhang, Xiao-Jia
Artemyev, Anton V.
Nakamura, Rumi
Yang, Jian
Angelopoulos, Vassilis
contents The magnetospheric substorm, which plays a crucial role in flux and energy transport across Earth's magnetosphere, features the formation of a thin, elongated current sheet in the magnetotail during its growth phase. This phase is characterized by a decrease in the equatorial magnetic field Bz and the stretching of magnetic field lines. Observing these large-scale magnetic field reconfigurations is challenging with single-point satellite measurements, which provides only spatially-localized snapshots of system dynamics. Conversely, low-altitude spacecraft measurements of energetic electron fluxes, such as those from ELFIN, offer a unique opportunity to remotely sense the equatorial magnetic field in the magnetotail during substorms by measuring the latitudinal variations of energetic electron isotropic fluxes. Because of strong scattering caused by the curvature of magnetic field lines, energetic electrons in the magnetotail are mostly isotropic. Consequently, variations in their fluxes at low altitudes are expected to reflect the reconfiguration of the magnetotail magnetic field. To better understand the connection of electron flux variation at low altitudes and magnetic field reconfiguration during substorms, we compared low-altitude ELFIN observations with simulations from the Rice Convection Model (RCM). The RCM, which assumes fully isotropic electron distributions, provides a robust framework for describing energetic electron dynamics in the plasma sheet and determining the self-consistent magnetic field configuration during substorms. The comparison of ELFIN observations and RCM simulations confirms our interpretation of electron flux dynamics at low altitudes during the substorm growth phase and validates the use of such observations to infer magnetotail dynamics during substorms.
format Preprint
id arxiv_https___arxiv_org_abs_2505_06797
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Exploring the Magnetotail from Low Altitudes: Evolution of Energetic Electron Flux During the Substorm Growth Phase
Sun, Weiqin
Zhang, Xiao-Jia
Artemyev, Anton V.
Nakamura, Rumi
Yang, Jian
Angelopoulos, Vassilis
Space Physics
Plasma Physics
The magnetospheric substorm, which plays a crucial role in flux and energy transport across Earth's magnetosphere, features the formation of a thin, elongated current sheet in the magnetotail during its growth phase. This phase is characterized by a decrease in the equatorial magnetic field Bz and the stretching of magnetic field lines. Observing these large-scale magnetic field reconfigurations is challenging with single-point satellite measurements, which provides only spatially-localized snapshots of system dynamics. Conversely, low-altitude spacecraft measurements of energetic electron fluxes, such as those from ELFIN, offer a unique opportunity to remotely sense the equatorial magnetic field in the magnetotail during substorms by measuring the latitudinal variations of energetic electron isotropic fluxes. Because of strong scattering caused by the curvature of magnetic field lines, energetic electrons in the magnetotail are mostly isotropic. Consequently, variations in their fluxes at low altitudes are expected to reflect the reconfiguration of the magnetotail magnetic field. To better understand the connection of electron flux variation at low altitudes and magnetic field reconfiguration during substorms, we compared low-altitude ELFIN observations with simulations from the Rice Convection Model (RCM). The RCM, which assumes fully isotropic electron distributions, provides a robust framework for describing energetic electron dynamics in the plasma sheet and determining the self-consistent magnetic field configuration during substorms. The comparison of ELFIN observations and RCM simulations confirms our interpretation of electron flux dynamics at low altitudes during the substorm growth phase and validates the use of such observations to infer magnetotail dynamics during substorms.
title Exploring the Magnetotail from Low Altitudes: Evolution of Energetic Electron Flux During the Substorm Growth Phase
topic Space Physics
Plasma Physics
url https://arxiv.org/abs/2505.06797