ABSTRACT
Scale considerations are not the only an issue for deciding if some terms in the full system of Maxwell equations and constitutive laws can be neglected. When discussing the coupling of devices, it is also important to realize that different devices can have intrinsic or geometrical scales that differ orders of magnitude. In such scenarios the coupled problem is most easily split in computational domains. Computational electrodynamics gives, rather straightforwardly, a series of prescriptions for matching the interface conditions of the various domains. This chapter presents an example of a coupled problem. The use of scaling arguments is definitely not new to the field of computing in electromagnetic modeling. Well-known approximations are the so-called EQS (electro-quasi-static) and MQS (magneto-quasi-static) approximations. The conversion of continuous variables to discrete variables on the computation grid also has consequences for the particular discretization route that is followed when implementing discrete versions of the Maxwell equations.
