ABSTRACT
In this chapter, classical macroscopic electromagnetism is used to derive relations useful in NDE. The approach leads to relations between the magnetic vectors H, B , and M , and to the boundary conditions that are obeyed at the interfaces between magnetic and nonmagnetic materials. This approach assumes that magnetic phenomena can be explained in terms of circulating (amperian) current distributions, without relating them to electronic and atomic magnetic moments. 1 Such current distributions are shown in Fig. 15-1. If they are evenly distributed within the material, these currents tend to cancel out. However, if they are not uniformly distributed, regions will exist in which this cancellation does not occur. (<italic>a</italic>) Amperian currents uniformly distributed in a material and (<italic>b</italic>) nonuniformly distributed. https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781315272993/937201b5-ee77-4453-9e41-7e220cf5cb89/content/fig15_1.tif"/>
