Kinetic plasma turbulence behind the quasi-perpendicular bow shock

Abstract:

The magnetosheath serves as a link between the solar wind and the Earth's magnetosphere. To obtain realistic models of the Sun-Earth coupling one needs to account for processes taking place in the magnetosheath plasma. Spacecraft measurements indicate highly turbulent plasma flow inside the magnetosheath, with the turbulence character depending on the bow shock type and the spacecraft position with respect to the bow shock and the magnetopause. At scales of the order of proton gyroradius, kinetic effects starts to operate. Exploring turbulence at these scales is important for understanding processes of energy exchange in the interaction between structures of different scales, plasma energization and heating. These processes play a crucial role in energy transfer from the solar wind to the magnetosphere. Present study is devoted to statistical study of parameters of the kinetic-scale plasma turbulence at different regions inside the magnetosheath behind the quasi-perpendicular bow shock. We obtain frequency spectra of the ion flux fluctuations in the frequency range [0.01-10] Hz. We consider spectra shapes at different points inside the magnetosheath in order to find out boundaries' affection on the kinetic-scale processes in the magnetosheath plasma. We find out that processes governing kinetic-scale turbulence can vary across the magnetosheath. We also consider the level of intermittency of the ion flux and its evolution across the magnetosheath. We demonstrate events with low level of intermittency, in contrast of the constantly high level of the solar wind intermittency.