Current Sheets in the Earth Magnetotail: Plasma and Magnetic Field Structure with Cluster Project Observations

Thin current sheets having kinetic scales are an important plasma structure, where the magnetic energy dissipation and charged particle acceleration are the most effective. It is believed that such current sheets are self-consistently formed by the specific nonadiabatic dynamics of charged particles and play a critical role in many space plasma and astrophysical objects. Current sheets in the near-Earth plasma environment, e.g., the magnetotail current sheet, are readily available for in-situ investigations. The dedicated multi-spacecraft Cluster mission have revealed basic properties of this current sheet, which are presented in this review: typical spatial profiles of magnetic field and current density, distributions of plasma temperature and density, role of heavy ions and electron currents, etc. Being important for the Earth magnetosphere physics, the new knowledge also could provide the basis for advancement in general plasma physics as well as in plasma astrophysics.