TRANSITION TO AN ENHANCED INTERNAL TRANSPORT BARRIER

The role of E x B rotation shear in the internal transport barrier for mation is examined by means of a one-dimensional transport simulation based on the current-diffusive ballooning mode turbulence model. Delay ed transition to the enhanced improved transport was reproduced in the medium heating power range. The threshold power is strongly reduced b y the effect of rotation shear. Simulation including particle transpor t was also applied to NBI-heated plasmas and the steepness of density and temperature gradients is discussed.