CHAPTER VII - QUASI-STATIC ELECTROMAGNETIC FIELD

Abstract

This chapter discusses quasi-static electromagnetic field. The nature of the variable electromagnetic fields in matter depends greatly on the kind of matter and on the order of magnitude of the frequency of the field. The presence of eddy currents implies a dissipation of the field energy that appears as Joule heat. The energy dissipation can also be expressed in terms of the total magnetic moment M acquired by the conductor in the magnetic field. In a periodic field, the magnetic moment is a periodic function of time with the same frequency. This chapter also discusses skin effect. The exact solution of the problem of the skin effect depends not only on the shape of the conductor but also on the manner of the excitation of the current in it, that is, the nature of the variable external magnetic field that induces the current. The accelerated motion of a metal, however, is equivalent to the action of additional inertia forces on the conduction electrons.