ИСТИНА

The magnetosheath is known to be a highly turbulent region in front of the Earth magnetosphere. Magnetosheath turbulence is developing between two boundaries unlike the solar wind one. Present study considers magnetosheath plasma variations with very high time resolution (31ms) observed by the BMSW device onboard SPECTR−R spacecraft. Thus it is possible to obtain frequency spectra of plasma fluctuations at the high−frequency range (with frequencies from 0.01 to 10 Hz). Magnetosheath plasma fluctuations within this frequency range are not studied in detail yet. Both ion flux value and its polar angle variations are considered. We obtain more than 700 spectra and 70% of them can be described by two power laws with a break, i.e., a change of slope. We find out that flux spectra usually have break at higher frequencies versus the angle spectra. We also compare the frequency of break with the Larmor’s frequency for number of cases and find out that polar angle break frequency roughly matches the ion cyclotron frequency. The dependencies of spectra parameters such as slopes and break frequency on the plasma parameters are also considered.