Short-pulse wave scattering from a cylindrical shell with slit-coupled coaxial interior

In a previous frequency domain study by the authors (see ibid., vol.39, p.1085-97, Aug. 1991), it was shown that the hybrid ray-mode system format introduced for scattering from cylindrical targets with aperture-coupled waveguide-like interiors continues to provide a cogent observable-based parameterization of the scattering in the time domain. Utilizing rigorous as well as phenomenological constructs, causal arrivals and physical turn-on times for well convergent resonant expansions are identified for the wavefront-dominated exterior as well as for the guided-mode-dominated interior wave processes. The validity of this parameterization of the scattered field is confirmed by interpretation of reference data generated via direct numerical Fourier inversion from the frequency domain to the time domain. Although applied so far only to concentric cylindrical geometry and single mode propagation in the interior, it is anticipated that the formalism can also accommodate nonconcentric and noncircular configurations and higher mode operating regimes