Turbulence Suppression in Transport Barriers

Basic facts about transport barriers in toroidally confined plasmas are presented. The flow shear of poloidal plasma rotation is a common feature in the spontaneous and induced transport barriers as well and is considered as the basic cause of their formation. Basic ideas on the impact of flow shear on the radial transport are discussed. Different mechanisms for the generation of flow shears are considered and models for the transition to enhanced confinement states are sketched.