| Autor: |
Atilaw, T. Y.1 (AUTHOR) tsigeya@umich.edu, Akhavan‐Tafti, M.1 (AUTHOR), Al Shidi, Q.1 (AUTHOR), Pulkkinen, T. I.1 (AUTHOR), Fontaine, D.2 (AUTHOR), Le Contel, O.2 (AUTHOR), Slavin, J. A.1 (AUTHOR), Le, G.3 (AUTHOR), Chen, L.‐J.3 (AUTHOR), Reiff, P. H.4 (AUTHOR), Alqeeq, S. W.2 (AUTHOR) |
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| Zdroj: |
Journal of Geophysical Research. Space Physics. May2024, Vol. 129 Issue 5, p1-12. 12p. |
| Abstrakt: |
This paper aims to quantify the magnetospheric magnetic flux contents under moderate to intense space weather conditions using global simulations. This study is a companion to Akhavan‐Tafti, Atilaw, et al. (2023, https://doi.org/10.1029/2023JA031832) where magnetic flux evolution is presented for a catalog of storm events, using Heliophysics System Observatory (HSO) observations. For this study, we used the Space Weather Modeling Framework (SWMF) in Geospace configuration to study magnetic flux dynamics for a subset of their storm events (15 events). Simulations reliably resolve the storm‐time magnetic flux Bz and current density |J| asymmetries across the different storm phases. It is revealed that: relative to the quiet period, flux content is enhanced during the storm sudden commencement (SSC) phase in the dayside by ΔBz/Bz, quiet = +17%, and reduced in the nightside magnetosphere (r[RE] < −6 RE) by −15%. At the same time, the cross‐tail current is found to enhance (|J| = 2 nA/m2), which suggests the storm impact in the nightside magnetosphere is much earlier in the storm cycle than previously shown. Concurring with previous studies, a significant depletion of magnetic flux by up to −40%, with day‐night and dawn‐dusk asymmetries, can be seen during the main and recovery phases. This corresponds to the enhanced current density (|J| = 5–8 nA/m2) at ∼6 RE further confirming the role of ring current in driving magnetospheric dynamics during the main and recovery phases. This is in contrast with the SSC phase wherein the Chapman‐Ferraro and cross‐tail currents are the dominant current systems. Key Points: The nightside magnetospheric flux is impacted by the storm event earlier in the storm cycle than expected, (i.e., the SSC phase)Decrease in flux content of up to −40% within the inner magnetosphere for the main and recovery phases is associated with the enhanced ring currentStorm‐time asymmetries in magnetic flux and current density are well‐resolved throughout the storm phases [ABSTRACT FROM AUTHOR] |
| Databáze: |
GreenFILE |
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