  The generation of intrinsic rotation by turbulence and neoclassical effects
in tokamaks is considered. To obtain the complex dependences observed in
experiments, it is necessary to have a model of the radial flux of momentum
that redistributes the momentum within the tokamak in the absence of a
preexisting velocity. When the lowest order gyrokinetic formulation is used, a
symmetry of the model precludes this possibility, making small effects in the
gyroradius over scale length expansion necessary. These effects that are
usually small become important for momentum transport because the symmetry of
the lowest order gyrokinetic formulation leads to the cancellation of the
lowest order momentum flux. The accuracy to which the gyrokinetic equation
needs to be obtained to retain all the physically relevant effects is
discussed.
