  We calculate the optical force and torque applied to an electric dipole by a
spinning light field. We find that the dissipative part of the force depends on
the orbital energy flow of the field only, because the latter is related to the
phase gradient generalized for such a light field. As for the remaining spin
energy flow, it gives rise to an optical torque. The resulting change in the
optical force is detailed for different experimentally relevant configurations,
and we show in particular how this change is critical when surface plasmon
modes are involved.
