Intrinsic toroidal and poloidal flow generation in the background of ion temperature gradient turbulence

Abstract

The generation of intrinsic toroidal and poloidal flows in the background of ion temperature gradient (ITG) driven microturbulence has been studied. It is shown that the dynamics of mean toroidal and poloidal flows is coupled. The radial fluxes of toroidal and poloidal momentum have been derived. It is shown that the polarization drift driven toroidal momentum flux is independent of mean flow shear and hence complements the shear driven ⟨k∥⟩ symmetry breaking mechanism (Gurcan et al 2007 Phys. Plasmas 14 042306) of intrinsic rotation. The radial flux of poloidal momentum due to polarization drift is found to vanish at the steady state. Comparison of residual toroidal and poloidal momentum fluxes, in the absence of seed flows, shows that toroidal flow dominates over poloidal flow.