Collisional transport of momentum in axisymmetric configurations

Calculations of the cross-field transport of toroidal momentum are presented for the collision-dominated regime in devices with an axisymmetric magnetic configuration. Intended as a point of reference for more complex calculations of transport in the low collision frequency regime, the development treats the case of pure toroidal flow and closely parallels previous calculations of collisional thermal conductivity in tokamaks. Certain counter-intuitive features of previous fluid-regime calculations of momentum diffusion are removed, and the contribution of viscous heating to the ion energy balance is discussed. A relation between internal disruptions (sawtooth oscillations) and momentum transport is proposed.