Abstract:
In support of the Comprehensive Test Ban, research is underway on the long-range propagation of signals from nuclear explosions in the deep underwater sound (SOFAR) channel. Our work has emphasized the variation of wave properties and source region energy coupling as a function of height or depth of burst. Initial calculations on CALE, a two-dimensional hydrodynamics code developed at LLNL by Robert Tipton, were linked at a few hundred milliseconds to a version of NRL's weak shock code, NPE, which solves the nonlinear progressive wave equation [B. E. McDonald and W. A. Kuperman, J. Acoust. Soc. Am. 81, 1406--1417 (1987)]. The wave propagation simulation was then followed down to 5000-m depth and out to 10 000-m range. In the future, calculations on a linear acoustics code will extend the propagation to greater distances. Until recently our research has considered only explosions in or above the deep ocean. New results on energy coupling and signal propagation in shallow water and the effects of other improvements will be presented. [Work performed under the auspices of the U. S. Department of Energy by the Lawrence Livermore National Laboratory under Contract W-7405-ENG-48.]