By extending the theory of functions of Green developed recently by M. S. Kushwaha and B. Djafari-Rouhani [1] to a cylindrical system of one and two interfaces under the action of an axial external magnetic field, we study the excitation modes of a confined plasma in the Faraday's geometry. The inverse response function of the system is obtained explicitly, in the nonretarded limit, that allowed to obtain several physical properties of the collective modes, like its dispersion law and its spectral power.