Application of Differential Invariant Method for Solving the Electromagnetic Fields.

We study the first integral and the solution of electromagnetic field by Lie svnmietry technique and the differential invariant method. The definition and properties of differential invariants are introduced and the infinitesimal generators of Lie symmetries and the differential invariants of electromagnetic field are obtained. The first integral and the solution of electromagnetic field are given by the Lie symmetry technique and the differential invariants method. A typical example is presented to illustrate the application of our theoretical results. [ABSTRACT FROM AUTHOR]