Аннотация:The mixing of magnetosheath and plasma sheet plasma in LLBL is studied on the base of Interball/Tail probe observations. Variations of the fluxes of ions and electrons and the magnetic field are analyzed. The thickness of LLBL for a number of cases is evaluated. The dependence of LLBL thickness on the changes of solar wind magnetic field and velocity is investigated. The connection between the solar wind magnetic field direction and the turbulent fluctuations of magnetosheath magnetic field is analyzed. The influence of magnetosheath magnetic field fluctuations on the magnetopause stress balance is discussed. It is shown that one of the main factors determining the formation and structure of LLBL is the turbulent nature of magnetic field and plasma fluctuations in the magnetosheath.