A new method to suppress reflections from numerical boundaries in wave propagation

To suppress numerical reflections, various boundary conditions, such as the transparent boundary condition (TBC), the absorbing boundary condition (ABC), and the perfectly matched layer (PML), are used in wave propagation methods. We propose a new boundary condition that works directly on the field. We show through examples that the field domain boundary condition (FDBC) performs as well as the ABC and the PML. It is much easier to implement as it requires only multiplication of the field in the absorbing layer by a factor. Another advantage with the FDBC is that its performance does not depend critically on the choice of numerical parameters such as the absorption profile and the strength of absorption.