Nonlinear distortions of elliptical light beams

An analysis is made of nonlinear distortions of hyper-Gaussian and hypertubular beams and pulses having different ellipticities of the amplitude profile. The optimal ratio of the beam radii is determined and this makes it possible to minimize the beam width beyond a layer of a defocusing medium exhibiting a thermal nonlinearity mechanism. It is shown that by changing to an elliptical profile one can increase the peak intensity of the optical radiation at the receiver and compensate a lateral displacement of the center of gravity of the beam. One of the maxima of an annular beam is trapped by an unbleached region of a moving cloudy medium. A possible geometry of a transparent channel is discussed.