Nonlinear RF-driven sheared flows in toroidal geometry

The modification of background plasma flows in a tokamak by applied rf waves is of interest as a possible means of controlling turbulence, triggering the formation of internal transport barriers. Here we e xtend p revious work by developing the standard neoclassical treatment to enable i) an evaluation of localized (in radius) poloidal and toroidal forces by the rf, ii) a rigorous calculation of the resulting poloidal and toroidal flow rates in the presence of neoclassical damping due to p lasma viscosity and a phenomenological radial diffusion of momentum, and iii) implicit t reatment of ambipolarity issues in the presence of rf. As an example, we c onsider I BW interaction within a narrow resonant i on-cyclotron layer where the wave absorption and rf forces occur.