ИСТИНА

We summarize the results of observations and theoretical analysis demonstrating the difference of the processes at geocentric distances from 6–7 Re till magnetopause near noon and till ∼10–12 Re near midnight versus the plasma sheet proper with magnetic field lines stretched in the antiearthward direction. The first selected region has the form of plasma ring with the characteristics near to the plasma sheet proper. Plasma pressure in the ring is larger than in the plasma sheet proper and the magnetic field lines have dipole like characteristics. Transverse currents in the surrounding the Earth plasma ring are closed inside the magnetosphere. Nightside part of the ring was previously selected as near the Earth plasma sheet. Magnetic field lines of the plasma sheet proper are stretched and its transverse currents are closed by magnetopause currents. It is a rather turbulent region with large fluctuations of plasma velocity and magnetic field filled by bursty bulk flows (BBF), thin current sheets, beams etc. Plasma pressure at geocentric distances 6–7 Re is near to isotropic. Such feature gives the possibility to use plasma pressure as the natural marker of the magnetic field line as in the condition of the magnetostatic equilibrium plasma pressure has the constant value along the field line. We compare values of plasma pressure measured at low latitudes by DMSP satellites and plasma pressure measured at the equatorial plane. We show that the main part of the discrete auroral oval is mapped to the surrounding the Earth plasma ring. Such feature explains the existence of quite comparatively stable auroral arcs inside the oval. Mechanisms of arc formation are discussed and compared with the results of experimental observations. The obtained picture of auroral domain mapping became rather useful for the explanation of different events during magnetic storms when auroral oval move to low latitudes and greatly expands. We demonstrate the localization of the region of the acceleration of electrons of the outer electron radiation belt inside the auroral oval and discuss the mechanisms of the acceleration of relativistic electrons frequently named electrons-“killers”.