ABSTRACT
In sections 2.3 and 2.4, we presented general solutions of the field equations in the case when a plane wave interacts with a particle of simple geometry; we there stressed the mathematical aspects. Usually, when we want to extract numbers from the theory for a specific astronomical application, we have to deliver ourselves to the mercy of a computer. No matter how efficient such a machine, it is wise to retain some mental independence and bring to one’s mind the physical aspects: computing must not be confused with understanding. In a few simple configurations, analytical solutions are possible and we turn to them in this chapter.
