Coherent and Incoherent Contributions to Multisoliton Complexes

We analyze multisoliton complexes and their dynamics in Kerr-like nonlinear media. The field in each of M incoherently interacting components is calculated using an integrable set of coupled nonlinear Schr\"odinger equations. We obtain a general N-soliton solution describing propagation of multisoliton complexes and their collisions. The evolution of such higher-order soliton beams is determined by coherent and incoherent contributions from fundamental solitons. These internal interactions are revealed and illustrated by numerical examples. This theory can be applied to describe the properties of incoherent solitons in a photorefractive medium since these are, essentially, multisoliton complexes.