Nonreflecting Boundary Conditions for Time-Dependent Scattering

An exact nonreflecting boundary condition was derived previously for use with the time dependent wave equation in three space dimensions. Here it is shown how to combine that boundary condition with finite difference methods and finite element methods. Uniqueness of the solution is proved, stability issues are discussed, and improvements are proposed for numerical computation. Numerical examples are presented which demonstrate the improvement in accuracy over standard methods.