Time-delayed autosynchronization

Fig. 5.4. Control of chaotic front dynamics by extended time-delay autosynchronization, a) Space-time plot of the uncontrolled charge density, and current density J vs. time, b) Same with global voltage control with exponentially weighted current density (denoted by the black curve). Parameters as in Fig. 1, U = 1.15 V, t = 2.29 ns, K = 3 x 10- Vmm2/A, R = 0.2, a = 10 s-b [73]...

In conclusion, time-delay autosynchronization represents a convenient and simple scheme for the self-stabilization of high-frequency current oscillations due to moving domains in superlattices under dc bias. This approach lacks the drawback of synchronization by an external ultrahigh-frequency forcing, since it requires nothing but delaying of the global electrical system output by the specified time lag. 

C. Beta, M. Bertram, A. S. Mikhailov, H. H. Rotermund, and G. Ertl Controlling turbulence in a surface chemical reaction by time-delay autosynchronization, Phys. Rev. E 67, 046224 (2003). 

J. Unkelbach, A. Amann, W. Just, and E. Scholl Time-delay autosynchronization of the spatio-temporal dynamics in resonant tunneling diodes, Phys. Rev. E 68, 026204 (2003). 

The information contained in the low-frequency part of the current (Fig. 5.4(a), black curve) is then used as input in the extended multipletime autosynchronization scheme. The voltage U across the superlattice is modulated by multiple differences of the filtered signal at time t and at delayed times t — t... 

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