Abstract

Using approximate analytical calculations based on the WKB and adiabatic approximations for the mode representation of the field, as well as numerical simulation based on the theory of adiabatic modes, geometric acoustic approximation, and the parabolic equation method, the patterns of the formation and propagation of caustic and weakly diverging acoustic beams in a horizontally inhomogeneous refractive oceanic waveguide are studied. The horizontal distance regions are determined at which the dependences of the acoustic field intensity on the horizontal distance typical of caustic and weakly diverging beams are retained. The study considers the processes involved in reformation of caustic and weakly diverging beams in an oceanic waveguide with increasing water layer depth and constant sound speed profile, which near the source characterized an underwater sound channel open toward the bottom. The conditions are formulated for an effectively matched transition of shallow-water waveguide modes refracted in the thermocline and interacting with the bottom to purely refracted modes of the underwater sound channel in a relatively deep water part of the oceanic waveguide.

中文翻译：

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水平非均匀海洋波导中的腐蚀性和弱发散光束

摘要

使用基于WKB和绝热近似的近似解析计算进行场模式表示，以及基于绝热模理论，几何声近似和抛物线方程法进行的数值模拟，形成和传播模式研究了水平非均匀折射海洋波导中的腐蚀性和弱发散声束。确定水平距离区域，在该区域保持声场强度对苛性和弱发散束典型的水平距离的依赖性。该研究考虑了随着水层深度的增加和声速分布的恒定，海洋波导中的苛性和弱发散光束的重整过程，在声源附近的特征是水下声音通道向底部开放。为在温跃层中折射的浅水波导模式的有效匹配过渡制定了条件，并在海洋波导的相对深水部分与水下声通道的底部相互作用到纯折射模式。