Study of turbulence in the central plasma sheet during quiet and substorm time intervals using the Interball-Tail satellite data

Recent studies are shown that the turbulent processes in the space plasmas are very important. It includes the behavior of the plasma sheet plasma during geomagnetic substorms. Study of the plasma turbulence in the central plasma sheet were made using the Corall instrument onboard Interball-Tail satellite. Fluctuations of the plasma bulk velocity across the plasma sheet, and corresponding eddy-diffusion coefficients, were calculated for different locations inside the plasma sheet. It was found that all components of eddy diffusion coefficients have a very wide range of values, generally between 104 and 106 km2/s. However, their average values increase with the distance from the Earth in the tailward direction for both quiet and substrom time intervals. Nevertheless, it also was the values of eddy-diffusion coefficients increase a few times during substorms in comparison with quiet time intervals, especially at the distances of 15-20 Earth's radii. We also found that the eddy-diffusion coefficients increase with the ion temperature and decrease with the ion number density. These studies made it possible to create a three-dimensional distribution of the eddy-diffusion coefficients for quiet and substorm times and compare with those predicted by the Antonova and Ovchinnikov (1998) model for the turbulent plasma sheet.