THERMODYNAMIC CHARACTERIZATION OF ELECTROMAGNETIC-FIELDS

A systematic treatment of the thermodynamic properties of electromagnetic fields is presented. Many potential difficulties are avoided by using the pre-existing electric and magnetic fields as thermodynamic variables. Four sets of thermodynamic functions of state may be defined, all of which are interrelated by Legendre transformations, and 96 Maxwell relations may be derived. The functions of state expressed in terms of the pre-existing electromagnetic field variables are then used to determine how the various thermodynamic quantities of interest vary with the applied fields.