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Properties of current sheet thinning at x ∼− 10 to −12 R E
Author(s) -
Artemyev A. V.,
Angelopoulos V.,
Runov A.,
Petrokovich A. A.
Publication year - 2016
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
eISSN - 2169-9402
pISSN - 2169-9380
DOI - 10.1002/2016ja022779
Subject(s) - current sheet , plasma sheet , current (fluid) , current density , physics , ion , scaling , electron , geophysics , plasma , heliospheric current sheet , astrophysics , atomic physics , solar wind , magnetosphere , interplanetary magnetic field , geometry , nuclear physics , mathematics , quantum mechanics , thermodynamics , magnetohydrodynamics
We report on Time History of Events and Macroscale Interactions during Substorms (THEMIS) observations of current sheet thinning in Earth's magnetotail at around x =− 10 to −12 Earth radii. The THEMIS spacecraft configuration in October–December 2015 allows us to construct both gradients that contribute to the cross‐tail current densityj y = μ 0 − 1 ( ∂ B x / ∂z − ∂ B z / ∂x ) (GSM coordinates). For 17 events when the spacecraft observed a gradual B z decrease and j y increase, we find the following average scaling relations: for the current densityj y ∼ B z − 7 / 4 , for the lobe magnetic fieldB L ∼ B z − 1 / 4 , and for the plasma densityn i ∼ B z − 3 / 4 . We show that the temperature of ions and electrons decreases and the plasma pressure gradient ∂ p / ∂ x rapidly increases during current sheet thinning. The scaleL x = ( ∂ ln p / ∂x ) − 1decreases a few thousand kilometers. We also consider current carriers in thinning current sheets: both ion and electron current‐dominated current sheets, preferentially located near dusk and midnight, respectively, are found.