Born-series dispersion equations and Born-Kirchhoff propagators
Born序列频散方程和Born-Kirchhoff传播算子

Conventional Kirchhoff propagators are conceptually simple and applicable for wave propagation in laterally homogeneous media. Ray-Kirchhoff propagators are kinematically acceptable in the range of seismic frequencies for heterogeneous media, but theoretically suffer congenital deficiencies. In this paper we present a natural way to extend the conventional Kirchhoff propagators to heterogeneous media. The so-called Born-Kirchhoff propagators are designed in the wavenumber domain under Born-series approximation to account for large-angle waves in strong-contrast media. These wavenumber-domain propagators that usually become singular at high wavenumbers can be transformed into the space domain, which are unconditionally stable with the Kirchhoff-summation implementation. Various orders of the Born-Kirchhoff propagators are formulated with a target-oriented flexibility to handle local complex zones for wave propagation, seismic imaging, and velocity estimation. A complete accuracy analysis is conducted by Born-series dispersion equations to characterize the Born-Kirchhoff propagators' scale-dependence on wavelengths, propagation angles, and heterogeneities. Synthetic seismograms for a simple 2D model are calculated with the zeroth-order and first-order Born-Kirchhoff propagators in comparison with those generated by the boundary-element method.