Accession Number:

ADA317497

Title:

Systematic Splitting of Wavefields into Unidirectional Modes: Long-Range Asymptotic Methods for Weakly Uniform Media,

Descriptive Note:

Corporate Author:

NAVAL RESEARCH LAB WASHINGTON DC ANALYTICAL ACOUSTICS SECTION

Personal Author(s):

Report Date:

1996-08-08

Pagination or Media Count:

45.0

Abstract:

A series of pseudo-unitary transforms is devised and applied to the Helmholtz equation for a weakly nonuniform one-dimensional medium, decoupling the wave field in a consistent order-by-order way into counter-propagating modes. The result is a generalized form of dAlembert decomposition, providing an asymptotic solution without backscatter at arbitrary order. Low-order contributions correspond to the standard WKB approximation. Higher orders provide additional terms of potential importance in applications involving propagation over long ranges, e.g., long time-of-flight measurement and very-long-baseline interferometry. Evidence is presented that this decoupling scheme is equivalent to high-order Born approximations.

Subject Categories:

  • Numerical Mathematics
  • Radiofrequency Wave Propagation

Distribution Statement:

APPROVED FOR PUBLIC RELEASE