Intense current sheets in the magnetotail: Peculiarities of electron physics

In this paper we investigate intense (with current density larger than 15 nA/m(2)) thin (thickness is less than proton gyroradius) horizontal current sheets observed by Cluster in 2003 year in the Earth magnetotail. We compare observed profiles of the curlometer current density with particle currents and analytical estimates. We show that intense horizontal current sheets represent a particular class of current sheets where the almost all current density can be described by electron curvature currents. Intensification of these currents is provided by increase of the electron temperature anisotropy in of current sheets where parallel/antiparallel electron beams are found. The substantial part of the vertical pressure balance in such intense sheets can be supported by the local increase of the shear component of the magnetic field. We show that this is common property for intense current sheets observed in the magnetotail and in the laboratory experiments. The later measurements can help in understanding particular details, since spacecraft observations of such current sheets are relatively rare, especially due to their relation to localized active regions.