Using the ray method,an investigation has been
carried out on the structure of caustics in the wa- veguideassuming the canonical distribution of the sound
velocity with depth. Monochromatic point source of sound was on the axis of the
waveguide. There is considered water rays only. It is
shown that the spatial part of the phase of a running sound wave does not
contain the wave propagation direction and is
always a positive quantity. When the trajectories are calculated,it is assumed that inversion of
rays occurs at an angle of total internal reflection where the reflection
coefficient is equal to unity. This eliminates the horizontal part of the
trajectories. At other points, the reflection coefficient
is assumed to be zero, and the passing coefficient is equal to unity. With this
change in the calculation of ray’s trajectories, the basic structure of the caustics remained the same. It is shown that
the boundary line of the caustic is a number of foci in which rays intersect
with similar angles out of the source and have neighbour times of propagation.
Structure of the sound field along the boundary line of the caustic is
periodic. Its period coincides with the wavelength of the field radiated by the source.

Zverev, V.A. and Ivanova, G.K. (2005) On the Vertical Structure of the Sound Field in the Canonical Waveguide at Large Distances. Acoustical Journal, 51, 771-776.

Zverev, V.A., Ivanov, V.P. and Ivanova, G.K. (2010) Calculation of the Sound Field in the Ocean in Caustic Surfaces by the Ray Method. Proceedings of the 22nd Conference of the Russian Acoustic Society, Moscow, 15-17 June 2010 191-194.

Zverev, V.A., Ivanov, V.P. and Ivanova, G.K. (2011) Caustics in Underwater Sound Channel and Their Connection with the Wave Front of the Point Source. Ocean Acoustics, Proceedings of the 13th L. M. Brekhovskikh’s Conference, Moscow, 31 May-3 June 2011, 49-52.

Ivanov, V.P. and Ivanova, G.K. (2012) One Aspect of Sound Waves Propagation in Inhomogeneous Water Space. Proceedings of the 25th Conference of the Russian Acoustic Society, Moscow, 17-20 September 2012, 338-341.

Ivanov, V.P. and Ivanova, G.K. (2013) A New Concept of Calculation of Reflection and Passage Sound Waves on the Boundary of Liquid Spaces. Ocean Acoustics, Proceedings of the 14th L. M. Brekhovskikh’s Conference, Moscow, 17- 21 June 2013, 121-124.

Ivanov, V.P. and Ivanova, G.K. (2013) A New Concept of Calculation Coefficients of Relection and Passage Sound Waves on the Boundary of Liquid Spaces. Open Journal of Acoustica, 3, 72-79. http://dx.doi.org/10.4236/oja.2013.33012