AXISYMMETRIC PARAMETRIC RADIATION - WEAK INTERACTION-MODEL

In this paper the difference-frequency field of a a parametric acoustic radiator is approximated via a weak finite-amplitude solution of the second-order nonlinear paraxial wave equation (i.e., the nonlinear optical analog established by E. A. Zabolotskaya and R. V. Khokhlov [Sov. Phys. Acoust. 15, 35–40 (1969)]) obtained by expressing the primary waves of an axisymmetrically excited bifrequency piston projector in terms of a weighted sum of Gauss-Laguerre eigenmodes. By relating the fundamental (i.e., Gaussian) mode in the farfield of the projector to those of equivalent “Bessel beams” a closed-form expression for the difference-frequency field is thus obtained as a function of range. Following a review of the solution's phenomenological properties comparisons are made of predicted results and experimental data reported in the literature. © 1979, American Association of Physics Teachers. All rights reserved.