THEORY OF SELF-TRAPPED SPATIALLY INCOHERENT-LIGHT BEAMS

We present a modal theory of self-trapping spatially incoherent light beams in any general nonlinear media. We find that a self-trapped inco herent beam induces a multimode waveguide which guides the beam itself by multiply populating the guided modes. The self-trapping process al ters the statistics of the incoherent beam, rendering it localized. We find the conditions for self-trapping (''existence region'' in parame ter space) and the correlation function of the incoherent self-trapped beam.