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Configuration of the Earth’s Magnetotail Current Sheet
Author(s) -
Artemyev Anton,
Lu San,
ElAlaoui Mostafa,
Lin Yu,
Angelopoulos Vassilis,
Zhang XiaoJia,
Runov Andrei,
Vasko Ivan,
Zelenyi Lev,
Russell Christopher
Publication year - 2021
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 - 10.1029/2020gl092153
Subject(s) - substorm , current sheet , plasma sheet , physics , magnetosphere , current (fluid) , geophysics , instability , plasma , isotropy , mechanics , heliospheric current sheet , magnetohydrodynamics , interplanetary magnetic field , solar wind , optics , quantum mechanics , thermodynamics
The spatial scale and intensity of Earth’s magnetotail current sheet determine the magnetotail configuration, which is critical to one of the most energetically powerful phenomena in the Earth’s magnetosphere, substorms. In the absence of statistical information about plasma currents, theories of the magnetotail current sheets were mostly based on the isotropic stress balance. Such models suggest that thin current sheets cannot be long and should have strong plasma pressure gradients along the magnetotail. Using Magnetospheric Multiscale and THEMIS observations and global simulations, we explore realistic configuration of the magnetotail current sheet. We find that the magnetotail current sheet is thinner than expected from theories that assume isotropic stress balance. Observed plasma pressure gradients in thin current sheets are insufficiently strong (i.e., current sheets are too long) to balance the magnetic field line tension force. Therefore, pressure anisotropy is essential in the configuration of thin current sheets where instability precedes substorm onset.