Improvement of the Constrained Interpolation Profile Method for LEMP Simulations

Abstract

The constrained interpolation profile (CIP) method is one of the finite-difference methods. In principle, the CIP method can suppress numerical dispersion and instability even when a relatively coarse grid is used. However, the M-type and C-type CIP methods, proposed as of today, can deal with neither conductor in the air nor imperfectly conducting ground. In this article, the CIP method is improved and extended to be capable of considering the presence of conductors in air and imperfectly conducting ground. This extended CIP (X-CIP) method does not use the direction-splitting technique, which is used in the conventional CIP methods and makes it difficult to represent conductors in air. The X-CIP method is applied to the simulations of lightning electromagnetic pulses over a perfectly or imperfectly conducting ground and associated surges on conductors in air, and the computed results are compared with those computed theoretically or using the finite-difference time-domain method.