ABSTRACT
In this chapter we discuss a scattering problem that can be characterized by a simple but extremely powerful mathematical model: the random walk on a plane. This model has a wide range of applications throughout science and engineering and many of its statistical properties were derived early in the last century [1-3]. In the present context it provides a description of scattering by a finite collection of discrete objects. It is an essentially exact model for light scattering by small particles, and in this chapter we shall often derive results and use experimental illustrations based on such systems (see, for example, References 4 and 5). However, the model is equally relevant to microwave scattering from raindrops or electron scattering from atomic defects, and it will be demonstrated in later chapters that it also provides a good representation for many aspects of scattering by continuous systems, such as rough surfaces and turbulent media.
