Author(s)

Ignacio Campos-Flores¹, José Luis Jiménez-Ramírez¹, José Antonio Eduardo Roa-Neri^2*

¹Departamento de Física, Facultad de Ciencias, Universidad Nacional Autónoma de México, Mexico City, México.
²área de Física Teórica y Materia Condensada, División de Ciencias Básicas e Ingeniería, Universidad Autónoma Metropolitana Unidad Azcapotzalco, Mexico City, México.

We give theoretical foundation to torque densities proposed in the past, like the one used by Beth to study experimentally the action of circularly polarized radiation on a birefringent material, or that proposed by Mansuripur to resolve a seeming paradox concerning the Lorentz force law and relativity. Our results provide new insights into electromagnetic theory, since they provide a unified and general treatment of the balance of lineal and angular momentum that permits a better assessment of some torques. Thus in this work we extend the derivations we have made of balance equations for electromagnetic linear momentum to balance equations for electromagnetic angular momentum. These balance equations are derived from the macroscopic Maxwell equations by means of vector and tensor identities and from the different ways in which these equations are written in terms of fields E, D, B, and H, as well as polarizations P, and M. Therefore these balance equations are as sound as the macroscopic Maxwell equations, with the limitations of the constitutive relations.

Balance Equations, Foundations of Electrodynamics, Electromagnetic Angular Momentum, Macroscopic Maxwell Equations, Abraham-Minkowski Controversy

Campos-Flores, I. , Jiménez-Ramírez, J. and Roa-Neri, J. (2017) Balance Equations of Electromagnetic Angular Momentum. Journal of Electromagnetic Analysis and Applications, 9, 203-217. doi: 10.4236/jemaa.2017.912017.