Properties of current sheet thinning at x ∼− 10 to −12 RE

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AbstractWe 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 density (GSM coordinates). For 17 events when the spacecraft observed a gradual Bz decrease and jy increase, we find the following average scaling relations: for the current density , for the lobe magnetic field , and for the plasma density . We show that the temperature of ions and electrons decreases and the plasma pressure gradient ∂p/∂x rapidly increases during current sheet thinning. The scale decreases 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.