Optical turbulence in wide gain section lasers: An analogy with large aspect ratio fluids.

The close synergism between experiment and theory for Rayleigh-Benard fluid convection has led to the development of sophisticated theoretical models which accurately predict the onset of widely diverse pattern forming turbulent convection. Close to threshold a multiple scales weakly nonlinear analysis yields a universal class of amplitude equations which accurately predict the formation of roll, hexagon, defect patterns and various instabilities of the underlying roll solutions. An elegant study by Busse of the nonlinear regime established that turbulent patterns and stable rolls could coexist beyond the first instability threshold.