On the width of a pedestal in the H-mode

The thickness of the transport barrier at the plasma edge is discussed, by analyzing the structure of the interface region between the turbulent L-mode region and the region where the transport is strongly-stabilized by the electric field. The effect of this localized radial electric field is prescribed. The spatial profile of turbulence intensity is analyzed by using a simplified model, in which the suppression and transport of turbulence intensity are introduced. The scaling property of the transport barrier is discussed.