Gyrokinetic Theory and Simulation of Angular Momentum Transport

A gyrokinetic theory of turbulent toroidal angular momentum transport as well as modifications to neoclassical poloidal rotation from turbulence is formulated starting from the fundamental six-dimensional kinetic equation. GyroBohm-scaled transport is evaluated from toroidal gyrokinetic simulations using the GYRO code [1]. The simulations quantify the two pinch mechanisms in the radial transport of toroidal angular momentum: the slab geometry ExB shear pinch [2] and the toroidal geometry ``coriolis'' pinch due to finite parallel velocity [3]. The pinches allow the steady-state null stress (momentum transport) condition required for intrinsic toroidal rotation in heated tokamaks without an internal source of torque [4]. A predicted turbulent shift in the neoclassical poloidal rotation [5] may be significant. \newline [1] J. Candy and R.E. Waltz, J. Comp. Phys. \textbf{186}, 545 (2003). \newline [2] R.R. Dominguez and G.M. Staebler, Phys. Fluids \textbf{B5}, 387 (1993). \newline [3] A.G. Peeters, et al., Phys. Rev. Lett. \textbf{98}, 26503 (2007). \newline [4] G.M. Staebler, et al., Bull. Am. Phys. Soc. \textbf{46}, 221 (2001). \newline [5] G.M. Staebler, Phys. Plasmas \textbf{11}, 1064 (2004).