Nonlinear propagation in Kerr media of beams with unequal transverse widths

We investigate three-dimensional propagation in bulk Kerr media of beams possessing different widths in the two transverse dimensions, under the combined effects of self-focusing and diffraction. This allows us to elucidate the process of self-trapping and provides a quantitative interpretation of recent experimental observations of beam self-deflection [Barthelemy et al., Opt. Lett. 17, 844 (1992)].