SUMMARY
We propose a method for one-step wave extrapolation using lowrank symbol approximation. We use an analytic source to construct a complex wavefield. Lowrank decomposition is employed to approximate the mixed-domain space-wavenumber wave extrapolation symbol. We demonstrate the stability improvement of a one-step scheme over a two-step scheme when waves are propagated at large time steps, thus reducing the computational cost. For wave propagation in inhomogeneous media, a velocity gradient term can be included to achieve a more accurate phase function, especially when velocity variations are large. Additionally, we develop an absorbing boundary condition which is propagation-direction-dependent and can be incorportated in the wave extrapolation operator. It allows waves to travel parallel to the boundary, thus reducing artificial reflections at wide-incident angles.
