DIFICI mechanism

The same effect seems to be at play in the case of the recently proposed DIFICI mechanism [112] of structure formation. There also the system is convectively unstable and the structure generated is advected away (except in the case of a loop reactor) [108]. The structures observed in the related experiments [113] in an open tubular reactor would thus be a noise generated pattern in a convectively unstable system. 

The numerical integration of Equation (49) was carried out with periodic boundary conditions. Values of the parameters were the same as those for the Figure 15 with v = vq/2. For these conditions an = —14.0, U22 = 7.1, Tr = -6.9, A = 8.3. Thus, the heat plays the role of the activator (022 > 0), and the matter represents the inhibitor. The conditions of stability of the local system are fulfilled in this case and, hence, the spatially homogeneous steady state loses its stability through the DIFICI mechanism. The evolution of the spatiotemporal patterns of the temperature and concentration looks qualitatively similar to that shown in Figure 5. 

We demonstrate here that a differential flow may lead to an instability of an otherwise stable homogeneous steady state even if the system does not contain such an unstable subsystem as long as it consists of at least three dynamical variables. The previous analysis showed that a two-variable system may be destabilized by the differential flow only if one of the species is an activator. It is clear that the mechanism of this new instability must be fundamentally different from that of DIFICI and TI. The results imply that the class of systems that may be destabilized by the differential flow of their components to form inhomogeneous patterns is much wider than anticipated earlier. 

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See also in sourсe #XX -- [ ]

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