  A new mechanism for inducing convection during IR laser interaction with
water or any absorbing liquid is described theoretically. The numerical
simulations performed using the developed model show that the optical pressure
and ponderomotive forces produces water flow in the direction of the laser beam
propagation. In the later stage of interaction, when water temperature rises,
the Archimedes force becomes first comparable and then dominant producing
convection directed against the vector of gravitational acceleration (upward).
The theoretical estimates and the numerical simulations predict fluid dynamics
that is similar to the observed in the previous experiments.
