Magnetic energy in quasistatic systems

Abstract

Abstract Magnetic energy is often presented solely as an energy stored by an inductor or in a magnetic field, in contrast to electrostatic energy which is introduced through the concepts of electric interaction between point-charges. Quasistatics, with its many applications in everyday life and important pedagogical appeal, has many similarities to statics and can allow a discussion of magnetic energy in terms which reinforces the parallel between magnetostatics and electrostatics. With this goal in mind, we consider two simple examples in textbooks involving a parallel plate capacitor and a flattened solenoid, to discuss the interplay between the work of external forces, the work of the electric interaction forces between the charges and currents and the electric and magnetic energies stored in these devices.