Profiles of electron temperature and Bz along Earth's magnetotail
Abstract. We study the electron temperature distribution and the structure of the current sheet along the magnetotail using simultaneous observations from THEMIS spacecraft. We perform a statistical study of 40 crossings of the current sheet when the three spacecraft THB, THC, and THD were distributed along the tail in the vicinity of midnight with coordinates XB ∈ [−30 RE, −20 RE], XC ∈ [−20 RE, −15 RE], and XD ~ −10 RE. We obtain profiles of the average electron temperature ⟨Te⟩ and the average magnetic field ⟨Bz⟩ along the tail. Electron temperature and ⟨Bz⟩ increase towards the Earth with almost the same rates (i.e., ratio ⟨Te⟩/⟨Bz⟩ ≈ 2 keV/7 nT is approximately constant along the tail). We also use statistics of 102 crossings of the current sheet from THB and THC to estimate dependence of Te and Bz distributions on geomagnetic activity. The ratio ⟨Te ⟩/⟨Bz⟩ depends on geomagnetic activity only slightly. Additionally we demonstrate that anisotropy of the electron temperature ⟨T∥/T⊥⟩ ≈ 1.1 is almost constant along the tail for X ∈ [−30 RE, −10 RE].