ИСТИНА

We studied the evolution of ion and electron distribution functions, approximated by kappa distributions, in the plasma sheet with the distance from the Earth using the data of the THEMIS spacecraft mission. Five events were used to calculate the main parameters of the kappa distribution. For these events at least four spacecraft were aligned along the tail between approximately 7 and 30 Earth radii. It was found that for the majority of events the values of kappa increase tailwards. The observed radial profiles could be related to the inner magnetosphere sources of particle acceleration and to the net tailward transport of particles. This net transport is the result of a balance between the average regular bulk transport toward the Earth and the turbulent transport by eddies in the tailward direction.