Energy loss by charged particles in complex media

Abstract

The introduction of geometrical complexity into a dielectric structure radically alters the pattern of losses from a passing charged particle. Here we introduce an approach to the problem which is ideally suited to numerical work and to the treatment of complex geometry. We apply the method to losses in colloidal metallic systems where the local juxtaposition of surfaces produces a host of modes and consequent changes in the loss spectrum. We also calculate the ‘‘Smith-Purcell effect,’’ in which a particle passing over a grating may radiate energy into the vacuum. This method is powerful and flexible and will, we trust, open a class of materials to quantitative study.