Propagation of Blob in boundary of HT-7 tokamak

Intermittent characteristics of turbulence induced by coherent structures (Blob) are manifested clearly on the Langmuir probe signal of HT-7 tokamak. With conditional analysis, asymmetric characteristics of the intermittent bursts are demonstrated. The parameter of plasma inside the Blob is larger than the background plasma parameter. Due to the radial propagation of the coherent structures, the particle density and temperature profiles in the scrape-off layer (SOL) are non-exponential and flat away from the last closed flux surface(LCFS). Around the LCFS, large burst fluctuations are responsible for about 50% of the total transport. These experimental finds may imply that the coherent structures are distorted by the developed shear flow in the shear layer. In SOL region, the coherent stru