Conserved Currents of the Maxwell Equations with Electric and Magnetic Sources

Abstract

New Lagrangians, depending on the field strengths and the electric and magnetic sources are found, which lead to the Maxwell equations. One new feature is that the equations of motion are obtained by varying the Lagrangian with respect to both the field strengths and the sources. In this way, conserved currents can be found for the field strengths and the electric or magnetic sources. Furthermore, using the equations of motion, the electric or magnetic sources can be eliminated, leading to conserved currents for the field strengths only (in the presence of electric and magnetic sources). Another new feature is the construction of a Lagrangian invariant under the duality transformation for both field strengths and electric and magnetic sources. The conserved current, after the elimination of electric and magnetic sources, depends on the field strengths only. The conserved quantity is related to the total helicity of the electromagnetic field.