Ion-Scale Magnetic Flux Ropes and Loops in Earth's Magnetotail: An Automated, Comprehensive Survey of MMS data between 2017 and 2022

Andy Smith*, Weijie Sun, James A. Slavin, Jonathan Rae

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Magnetic reconnection is a critically important process in defining the dynamics and energy transport within plasma environments. In near-Earth space we may track where and when reconnection occurs by identifying associated coherent magnetic structures. On a global scale these structures facilitate the flow of mass and magnetic flux into, within, and out of the magnetospheric system, whilst contributing to local plasma heating. In the Earth's magnetotail there are two similar structures we identify in this work: magnetic flux ropes and loops. We present a robust, automated and model independent method by which encounters with such structures may be identified using the Magnetospheric Multiscale (MMS) mission. The magnetic structures are first identified through their magnetic field signatures at a single spacecraft (MMS1), including checks on the local minimum variance coordinate system. Next, the local curvature of the magnetic field is evaluated with all four MMS spacecraft. Finally, the plasma conditions are checked to ensure that the interpretation is fully self-consistent. We evaluate the data obtained by MMS between 2017 and 2022. In total we find 181 self-consistent magnetic flux ropes and 263 magnetic loops, which fit an exponentially decaying size distribution with a scale size comparable to the ion gyroradius (∼0.23 RE/1,400 km). If we remove the requirements on the plasma properties of the structure, we locate 648 potential magnetic flux ropes and 1,073 magnetic loops. The magnetic structures are preferentially observed in the pre-midnight region of the magnetotail, with most identifications occurring beyond 20 RE. All catalogs are provided to the community.
Original languageEnglish
Article numbere2023JA032231
Number of pages16
JournalJournal of Geophysical Research: Space Physics
Issue number3
Early online date16 Mar 2024
Publication statusPublished - Mar 2024

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