Improving the performance of Higdon non-reflecting boundary conditions by using weighted differencing

An improved version of the Higdon non-reflecting boundary scheme is presented, incorporating a weighting factor in the finite difference implementation. This weighting factor was mentioned briefly in the original Higdon papers but was not pursued further by Higdon or in subsequent development by later researchers. In this paper, we show analytically and by example that this weighting factor significantly improves the absorption properties of the boundary scheme, by as much as 99% over the unweighted scheme of the same order and 99.99% over the classic Sommerfeld radiation condition.