For citation:
Korzinov L. N., Nikulin A. S., Rabinovich M. I. Dynamics of defects in target pattern and origin of spirals with a high topological charge. Izvestiya VUZ. Applied Nonlinear Dynamics, 1994, vol. 2, iss. 2, pp. 73-80. DOI: 10.18500/0869-6632-1994-2-2-73-80
Dynamics of defects in target pattern and origin of spirals with a high topological charge
Recently, Ahlers and his group demonstrated remarkable experiments on the convection of gaseous CO2 in a large aspect ratio cylindrical cell. They discovered formation of stable multiarmed spirals (with the topological charge from 1 to 13). In this work it is shown that the multiarmed spiral is a result of the evolution of defects against the background of a cylindrical target. As a result of the interaction of the defects with the cylindrical structure and with each other the defects come to the target center and a stable multiarmed spiral is formed. The topological charge of this spiral depends on the initial number of defects of different signs. Analysis of the pattern evolution in the framework of the Swift — Hohenberg (SH) equation confirms this scenario of spiral formation. Taking into account small nonpotential terms in the frame of complex SH model it is possible to describe rotation of multiarmed spirals.
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