Investigation of the plasma periphery performed in the T-10 tokamak has revealed a strong dependence of the scrape-off layer (SOL) width on the average electron density. To explain the SOL widening several times increasing of the effective cross-field diffusion coefficient should be assumed. The increase of the effective cross-field diffusion coefficient is connected with a growth of non-diffusion radial transport in the SOL. This transport appears in formation of the plasma object with density two times higher that background density. Formation of the plasma objects is observed only in the scrape-off layer in the vicinity of the last closed flux surface about 1-2 cm from outside of the last closed flux surface (LCFS). The object formation is found to occur above a threshold level of the average electron density depending on the plasma current. Value of the threshold density amounts to about 0.3 of Greenwald density. Frequency of the objects formation is 3-4 kHz.
The plasma objects move radially to the wall of vacuum chamber. Their radial velocity is 450-600 m/s and does not display a radial dependence. In contrast to the radial velosity radial size of the plasma objects decreases with radius from 2.5-3 cm at LCFS to 0.5 cm near the wall. Plasma objects move also in poloidal direction. Poloidal velocity is 1000-1300 m/s and does not correspond to the speed of poloidal electric drift defined by stationary part of the radial electric field. Poloidal size of the plasma objects is about 2-3 cm.
In regime with electron cyclotron resonant plasma heating giant bursts appear in ion saturation current signal. These bursts are associated with plasma objects having a density 6-8 times higher one between the bursts. Distinguish feature of the giant plasma objects is obvious correlation of their appearance with confinement degradation.