f One-Way Operators in Laterally Varying Media

Currently, in constructing one-way operators for recursive wave field extrapolation, it is assumed that the medium parameters are constant witpin the lateral eitent of the operator. This means that for each gridpoint an operator is used which is related only to the local medium parameters at that gridpoint. In this abstract we call this approach "standard". For laterally smoothly varying media (i.e. smooth compared to the wavelength) the standard method leads to fairly accurate results. However, when the order of the lateral variations approaches the wave length scale, the results become unreliable and may even exhibit unstable behaviour (Etgen,1994).