The Fourth-Order Absorbing Boundary Conditions with Optimal Parameters

Artificial boundaries must be introduced to limit the area of computation in both seismic modeling and migration using the wave equation method,and absorbing boundary conditions(ABC) with relatively simpler computations are widely used to eliminate unwanted boundary reflections.However the lower order traditional absorbing boundary conditions are only effective for incident waves with smaller incident angles.A fourth-order absorbing boundary condition equation based on Higdon's ABC is deduced in this paper,and a new optimal algorithm is presented to automatically select the parameters of Higdon's ABC.Using the fourth-order absorbing boundary conditions can absorb incident waves with incident angles nearly from 0 to 90 degrees.Numerical tests confirm the effectiveness of the new approach.