In rounding out the education of students in advanced courses in applied electromagnetics it is
incumbent on us as mentors to raise issues that encourage appreciation of certain subtle aspects
that are often overlooked during first exposure to the field. One of these has to do with the
interplay between fields and potentials, with the latter often seen as just a convenient
mathematical artifice useful in solving Maxwell’s equations. Nonetheless, to those practiced in
application it is well understood that various alternatives in the use of fields and potentials are
available within electromagnetic (EM) theory for the definitions of energy density, momentum
transfer, EM stress–energy tensor, and so forth. Although the various options are all compatible
with the basic equations of electrodynamics (e.g., Maxwell’s equations, Lorentz force law, gauge
invariance), nonetheless certain alternative formulations lend themselves to being seen as
preferable to others with regard to the tra…