A FAST DIRECT SOLVER FOR HIGH FREQUENCY SCATTERING FROM A LARGE CAVITY IN TWO DIMENSIONS

We present a fast direct solver for the simulation of electromagnetic scattering from an arbitrarily shaped, large, empty cavity embedded in an infinite perfectly conducting half-space. The governing Maxwell equations are reformulated as a well-conditioned second kind integral equation, and the resulting linear system is solved in nearly linear time using a hierarchical matrix factorization technique. We illustrate the performance of the scheme with several numerical examples for complex cavity shapes over a wide range of frequencies.