Fluctuations of the Electric and Magnetic Fields in the Plasma Sheet of the Earth’s Magnetotail According to MMS Data

The spectra of fluctuations of electric and magnetic fields in the plasma sheet of the Earth’s magnetotail according to Magnetospheric Multiscale Mission data were statistically analyzed for the years 2017–2022 during periods with small plasma velocity. The results of measurements of the FIELDS instrument suite were considered. Three-hour intervals were identified, during which the satellites were inside the plasma sheet and the plasma parameter β > 1. Over 100 thousand spectra of fluctuations of the electric field by the EDP/DCE instrument and the magnetic field by the FGM instrument were analyzed. Intervals with plasma velocities exceeding 100 km/s were excluded. For each interval, the spectral indices were calculated in the frequency range 0.014–16 Hz. It is shown that the values of the spectral indices differ significantly for the electric and magnetic fields. The dependences of the spectral indices on the fluctuations of the electric and magnetic fields averaged over the interval are obtained.