CONTROL OF DEFECTS AND SPACELIKE STRUCTURES IN DELAYED DYNAMICAL-SYSTEMS

In many nonequilibrium dynamical situations delays are crucial in indu cing chaotic scenarios. In particular, a delayed feedback in an oscill ator can break the regular oscillation into trains mutually uncorrelat ed in phase, whereby the phase jumps are localized as defects in an ex tended system. We show that an adaptive control procedure is effective in suppressing these defects and stabilizing the regular oscillations . The analysis of the transient times for achieving control demonstrat es that stabilization is obtained within an amplitude turbulent regime , analogous to what is present in spatially distributed systems. The c ontrol technique is robust against the presence of large amounts of no ise.