An Adaptive Cip-Fem For The Polygonal-Line Grating Problem

This paper is concerned with the diffraction by a polygonal-line grating. We develop a continuous interior penalty finite element method based on the truncation of the nonlocal boundary operators for solving the problem. An a posteriori error estimate is derived for the method. The truncation parameter is determined through the truncation error of the a posteriori error estimate. Numerical experiments are also presented to show the efficiency and robustness of the proposed adaptive algorithm.