Motion of optically dense liquid drops in a laser radiation field

A qualitative analysis of the flow of the liquid in a drop and of the internal heat problem is used to obtain approximate expressions for estimating the forces causing the motion of water drops of R$\gtrsim$10$^{-3}$ cm radius along a 10.6$\mu$ CO$_2$ laser beam of 10$^3$ W/cm$^2$ intensity. The validity of these expressions is supported by experimental results. An empirical expression is obtained for a force acting on a drop when the radiation intensities are close to the thermal explosion threshold.