Scattering by truncated targets with and without boundary interactions

Ray methods have been applied to the scattering of various truncated targets having wavenumber-radius products as small as 10 [F. J. Blonigen and P. L. Marston, J. Acoust. Soc. Am. 107, 689–698 (2000); S. F. Morse and P. L. Marston, ibid. 112, 1318–1326 (2002); B. T. Hefner and P. L. Marston, ARLO 2, 55–60 (2001)]. Recent work emphasizes the exploration of scattering enhancements for other situations including plastic cylinders having curved ends, truncated plastic cones, partially exposed cylinders, and objects in simulated conditions for burial in a seabed. Enhanced scattering is often associated with a locally flat outgoing wavefront. For plastic targets it has been helpful to examine the time dependence of the backscattered envelope as a function of target tilt for targets illuminated by short tone bursts. For partially exposed objects it is helpful to examine the backscattering as a function of the target exposure. For simulated buried targets, it has been helpful to excite target resonances. [Work supported by the Office of Naval Research.]