ИСТИНА

Plasma flows with high values of Reynolds numbers are unstable and create high level of turbulence. Such kind of flows is observed in the plasma sheet of the magnetosphere of the Earth. Turbulent flows in the plasma sheet involve large scale (with scales ~1Re) vortexes, thin current sheets, dipolarization fronts, bursty bulk flows (BBF) and others. Each of such large scale elements of turbulence produces plasma transport and is studied separately. Eddy diffusion coefficient is one of the characteristics of plasma sheet turbulence. We compare the results of observations of eddy diffusion coefficient obtained using data of ISEE, INTERBALL, Geotail, CLUSTER and THEMIS projects. We demonstrate the coincidence of such results with the predictions of the model of quasiequilibrium turbulent plasma sheet. We also show that the region of high turbulent fluctuations has the inner boundary localized near to ~10Re. We obtain the statistical picture of BBF observations during different phases of magnetospheric substorm and analyze the possible role of BBF in the development of turbulence and substorm triggering. We show that the frequency of BBF observations does not coincide with the frequency of substorm onsets and substorm onset can be observed in the absence of BBF in the tail. The nature of BBF formation is discussed. We show that the observed results support earlier suggested theory of substorm onset which explains current disruption and tail reconnection after onset.