Speckle instability in strongly scattering Kerr random media

Summary form only given. Using the wave automaton, a numerical tool we developed to describe the full dynamics of (scalar) waves in complex media, we simulate wave propagation in two dimensional quenched disordered media in the presence of a Kerr nonlinearity. Under suitable condition of disorder and nonlinear perturbation, we observe a speckle instability even in absence of scatterer motion, which results from the positive feedback provided by the scattering medium.