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MMS Study of the Structure of Ion‐Scale Flux Ropes in the Earth's Cross‐Tail Current Sheet
Author(s) -
Sun W. J.,
Slavin J. A.,
Tian A. M.,
Bai S. C.,
Poh G. K.,
AkhavanTafti M.,
Lu San,
Yao S. T.,
Le G.,
Nakamura R.,
Giles B. L.,
Burch J. L.
Publication year - 2019
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2019gl083301
Subject(s) - current sheet , rope , flux (metallurgy) , physics , magnetic flux , magnetic field , plasma sheet , geophysics , magnetic reconnection , current (fluid) , computational physics , magnetosphere , magnetohydrodynamics , materials science , structural engineering , engineering , metallurgy , thermodynamics , quantum mechanics
Abstract This study analyzes 25 ion‐scale flux ropes in the Magnetospheric Multiscale (MMS) observations to determine their structures. The high temporal and spatial resolution MMS measurements enable the application of multispacecraft techniques to ion‐scale flux ropes. Flux ropes are identified as quasi‐one‐dimensional (quasi‐1‐D) when they retain the features of reconnecting current sheets; that is, the magnetic field gradient is predominantly northward or southward, and quasi‐2‐D when they exhibit circular cross sections; that is, the magnetic field gradients in the plane transverse to the flux rope axis are comparable. The analysis shows that the quasi‐2‐D events have larger core fields and smaller pressure variations than the quasi‐1‐D events. These two types of flux ropes could be the result of different processes, including magnetic reconnection with different dawn‐dusk magnetic field components, temporal transformation of flattened structure to circular, or interactions with external environments.