Physics Letters A 249 (1998) 2861294 Self-focusing in the complex Ginzburg1Landau limit

We analyze self-focusing and singularity formation in the complex Ginzburg1Landau equation (CGL) in the regime where it is close to the critical nonlinear Schrödinger equation. Using modulation theory [Fibich and Papanicolaou, Phys. Lett. A 239 (1998) 167], we derive a reduced system of ordinary differential equations that describes self-focusing in CGL. Analysis of the reduced system shows that in the physical regime of the parameters there is no blowup in CGL. Rather, the solution focuses once and then defocuses. The validity of the analysis is verified by comparison of numerical solutions of CGL with those of the reduced system. c ○ 1998 Elsevier Science B.V