THE VARIATIONAL PRINCIPLE FOR NONLINEAR-WAVES IN DISSIPATIVE SYSTEMS

We discuss the application of the variational principle to nonlinear d issipative systems, in particular the nonlinear Schrodinger (NLS) equa tion with diffusive and damping terms. The proposed variational method is an old, but little known technique. We use a simple example to ill ustrate the technique and then make some general comments concerning t he NLS with damping and diffusive terms.