Plasma sheet and magnetosheath plasma mixing in LLBL: Case study Original Research Article

Low latitude boundary layer (LLBL) of the magnetosphere of the Earth is formed due to the mixing of magnetosheath and plasma sheet plasma. The mixing process is studied on the base of Interball/Tail probe observations. The variations of the fluxes of ions (measured by CORALL instrument), electrons (measured by ELECTRON instrument) and particles with energies more than 25 keV (measured by DOK-2 instrument) are analyzed for the case of 21 September 1995 when the satellite intersects LLBL/plasma sheet boundary on the GSM (−4.1, −13.6, 2.2) Re distance. The variations of the magnetic field measured by MIF instrument are compared with the variations of particle fluxes. The thickness of the boundary region containing plasma from LLBL is estimated. The stress balance across the analyzed boundary is discussed. We find that the plasma pressure inside the LLBL is essential in understanding the pressure balance across the magnetopause.