SPATIAL PATTERNS IN A PASSIVE RING CAVITY WITH ATOMS

We present numerical simulations of a simplified model for the ring ca vity device in the case of round-trip time equal to the atomic radiati ve lifetime. Real pattern effects are of primordial importance, especi ally in small systems where the boundary conditions seem the key for t he pattern selection. For a plane-wave input, our system displays not only hexagons, as in the mean-field model, but also stationary rolls, squares and octagons with a weakly chaotic structure. All these struct ures are also obtained in the case of bell-shaped input profile with l arge aspect ratio; they even appear regular and wonderful, as if bound ary effects stabilize them.