225 Macromol. Symp. 160, 225-232 (2000) New type of turbulence, or how symmetry results in chaos Michael I. Tribelsky Department of Applied Physics, Faculty of Engineering, Fukui University, Bunkyo 3-9-1, Fukui 910-8507, Japan E-mail: tribel@scroll.apphy.fukui-u.ac.jp Pattern formation and transition to chaos in a macroscopic dissipative sys- tem is discussed. It is supposed that the system has a continuous family of spatially uniform states, which can be transformed into each other by a certain symmetry transformation. If such a system undergoes instability against spatially periodic perturbations with a finite wavenumber, inter- play of short-wavelength modes associated with the instability and long- wavelengths modes generated by the symmetry transformation affects the dynamics of the system dramatically. In particular, it may result in direct transition from a spatially uniform state to spatiotemporal chaos, analo- gous to second order phase transition in equilibrium systems. The obtained results may be applied to kinetic of polymerization, to reaction-diffusion problems, to flame propagation, to some hydrodynamic problems, etc. In the present contribution I would like to call attention of polymer physicists and chemists to a new and very appealing phenomenon recently discovered in dissipa- tive systems, namely to direct transition from a spatially uniform state to spatiotem- poral chaos, called soft-mode turbulence. The phenomenon is quite common and may be observed, and definitely will be observed, in polymer systems too. I will be happy if I can encourage experts in polymer systems to look for possible manifesta- tions and applications of the soft mode turbulence. Despite detailed study of the phenomenon is associated with sophisticated mathematics, its main features, as usual, can be obtained based upon simple semi-qualitative arguments. In what fol- lows I will focus on this simplified approach to the problem. Those, who are inter- ested in subtle details of the analysis can find them (together with relevant refer- ences) in review ) 1 , which still reflects state of the art.