Beam Instabilities in the Scale Free Regime
  The instabilities arising in a one-dimensional beam sustained by the diffusive photorefractive nonlinearity in out-of-equilibrium ferroelectrics are theoretically and numerically investigated. In the "scale-free model", in striking contrast with the well-known spatial modulational instability, two different beam instabilities dominate: a defocusing and a fragmenting process. Both are independent of the beam power and are not associated to any specific periodic pattern. 
Viola Folli, Eugenio DelRe, Claudio Conti
physics.optics cond-mat.dis-nn cond-mat.mtrl-sci cond-mat.soft