Revista Brasileira de Ensino de Física
Print version ISSN 1806-1117
CAMPOS, I.; JIMENEZ, J.L. and LOPEZ-MARINO, M.A.. Electromagnetic momentum balance equation and the force density in material media. Rev. Bras. Ensino Fís. [online]. 2012, vol.34, n.2, pp.1-5. ISSN 1806-1117. http://dx.doi.org/10.1590/S1806-11172012000200006.
We present a momentum balance equation derived directly from Maxwell's equations. This equation contains a force density, which we call Maxwell's force density, which generalizes the Lorentz force density, now including total fields rather than only external fields, and arbitrary charge and current distributions. As a test for this balance equation we derive for gases the electrostatic and magnetostatic Helmholtz force densities. This deduction will be useful for advanced undergraduates and graduate students, as well as for specialists interested in the conceptual aspects of electromagnetism.
Keywords : Maxwell's equations; Balance equation; electromagnetic force density.