Transient intermittent structures in the plasma sheet-tail lobes interface.

Interball-1 observations shed a new light on the structure of the Plasma Sheet Boundary Layer (PSBL), which in general sense represent the complicated interface between hot quasi-isotropic Central Plasma Sheet (CPS) and Magnetotail Lobe regions which are commonly considered as being void of plasma. In reality this interface consists of intermittent short-lived plasma structures of various types: localized beams (beamlets), clouds (or filaments) of plasma resembling the one in the CPS and specific structures which could not be associated with two previous types. Standard picture of the PSBL holds therefore only in a very rough average sense and the transition from the Plasma Sheet (PS) to the lobes occurs via the multitude of transient plasma structures.