Momentum transport in the vicinity of qmin in reverse shear tokamaks due to ion temperature gradient turbulence

Abstract

We present an analytic study of momentum transport of tokamak plasmas in the vicinity of minimum safety factor (q) position in reversed magnetic shear configuration. Slab ion temperature gradient modes with an equilibrium flow profile are considered in this study. Quasi-linear calculations of momentum flux clearly show the novel effects of q-curvature on the generation of intrinsic rotation and mean poloidal flow without invoking reflectional symmetry breaking of parallel wavenumber (k∥). This q-curvature effect originates from the inherent asymmetry in k∥ populations with respect to a rational surface due to the quadratic proportionality of k∥ when q-curvature is taken into account. Discussions are made of possible implications of q-curvature induced plasma flows on internal transport barrier formation in reversed shear tokamaks.