Instability in vortex system in HTSC

The recent progress in understanding of the vortex system behaviour in HTSC gives an evidence for spatial and temporal chaos-vortex glass and vortex diffusion and, on the other hand, an evidence for collective phenomena such as vortex flow. A deterministic temporal chaos-diffusion-is responsible for 1/f like noise generation and for irreversibility. These phenomena are well pronounced in frequency dependence of magnetization. They cannot be explained by Anderson-Kim model of the critical state or any extended model. We suggest a novel concept of the critical state in type II superconductors which is based on the phase transition in the vortex system dynamics. This phase transition represents a transition between the chaotic and correlated transport. The role of pinning, in this concept, is suppressing the collective state creation