Nonlinear density wave propagation in layered superconducting plasmas

In the present work the propagation of nonlinear density waves in a superconducting layered structure has been investigated. It is seen that the nonlinear Schrodinger (NLS) equation governs the propagation of density waves in a superconducting plasma. It is shown that in general the NLS equation in this case is modulationally unstable. By using the Kronig-Penney model to depict the layered structure we derive a nonlinear dispersion relation relating the nonlinear analog of the Bloch wave number to the propagation frequency. This nonlinear dispersion relation is numerically investigated.