Study Of The Relationship Between Sol Width And Turbulence Transport On East

Plasma-wall interaction has been taken as a critical issues for the high-power,long-pulse, steady-state operations of tokamak. The width of the scrape-off layer (SOL)largely determines the heat and particle load that ultimately conducted to the unitsurface of the wall in either limiter or divertor configuration. In this thesis, therelationship between the SOL width and the turbulence transport has been studied insome detailed on the EAST superconducting tokamak using a fast reciprocating probesystem at the outer midplane.Probe measurements show that the radial correlation length of the turbule ncedecreases as the plasma current increases, while the poloidal correlation length changesinversely in radio-frequency heated H-modes on EAST. Further investigation indicatesthat this could be induced by the E shear in the SOL and thus has a significa ntimpact on the SOL width. In particular, a higher plasma current is accompanied by astronger E shear and a shorter radial correlation length of turbulence, thusresulting in a narrower power fall-off width. A simple model has been applied todemonstrate the suppression effect of E shear on turbulence in the SOL and showsqualitative agreement with the experimental results. The extrapolation for ITERtokamak has also been included.