Kinetic-scale plasma turbulence evolving in the magnetosheath: case study

Large set of in-situ measurements with high time resolution in the Earth's magnetosheath provides a great opportunity to explore influence of kinetic processes on the turbulent cascade in the collisionless plasma. Recent statistical studies reveal dependence of characteristics of the turbulent spectra on position of the viewing point behind the bow shock. Detailed analysis of dynamics of the turbulence inside the magnetosheath requires a case study prepared in several points. Present study deals with in-situ measurements of kinetic-scale fluctuations in two points located close to one stream line in different parts of the magnetosheath. We analyze fluctuation spectra of ion flux value and magnetic field magnitude in the frequency range 0.01-2 Hz obtained simultaneously from Spektr-R and Themis spacecraft. The range of frequencies corresponds to transition from magnetohydrodynamic range of scales to the scales where kinetic effects become dominant. We demonstrate deviation of turbulent cascade from the shape predicted typically by the models of developed turbulence in the vicinity of the bow shock and in the subsolar magnetosheath. We show the recovery of the spectral shape during plasma propagation toward the tail. Also, we consider influence of the upstream solar wind conditions on the evolution of turbulence in the magnetosheath.