Аннотация:The free access to data of THEMIS project observations gives the possibility to clarify many unresolved problems in the physics of the magnetosphere. One of such problems is the formation of low latitude boundary layer (LLBL). LLBL is formed on closed field lines at low latitudes near magnetopause due to penetration of magnetosheath plasma inside the magnetosphere. LLBL crossings by THEMIS satellite are analyzed. Results of observations support earlier conclusions on the existence of high level of magnetic field fluctuations in the magnetosheath. Dayside magnetic field configuration inside the magnetosphere is analyzed for the selected cases. It is shown that the amplitude of magnetosheath magnetic field fluctuations is higher than the value of the magnetic field under the magnetopause in the near cusp regions in the analyzed events. The role of such fluctuations in LLBL formation is discussed.