Modeling of the shear effects on the thermal ion transport in advanced tokamak scenarios (original) (raw)

Plasma shear effects on thermal ion transport in present advanced tokamak scenarios are analyzed. In order to overcome some limitations encountered from previous shear dependent models ͓e.g., V. Parail et al., Plasma Phys. Controlled Fusion 40, 805 ͑1998͒, and references therein͔, a semiempirical model combining the effects of the magnetic and EϫB rotation shears is proposed. These shear dependences are based on simple theoretical arguments from turbulence studies. The dominant stabilizing term of our shear correction is the shear in toroidal rotation. The predictive modeling of the formation and evolution of thermal ion internal transport barriers in relevant advanced scenarios of Tokamak Fusion Test Reactor ͓E. J. Synakowski et al., Phys. Plasmas 4, 1736 ͑1997͔͒, Doublet III-D ͑DIII-D͒ ͓B. W. Rice et al., Nucl. Fusion 36, 1271 ͑1996͔͒ and Joint European Torus ͑JET͒ ͓F. X. Söldner and the JET Team, Plasma Phys. Controlled Fusion 39, B353 ͑1997͔͒ with our shear correction is presented. A multimachine test of the model performed here provides a basis for predictive simulations of future experiments and for the optimization of advanced scenarios through plasma control.