UNDULATION INSTABILITY IN 2-DIMENSIONAL FOAMS OF MAGNETIC FLUID

Two-dimensional magnetic fluid foams are cellular structures whose fra mework is made of magnetic fluid. The features of these equilibrated p atterns are driven by a control parameter: the amplitude of the applie d magnetic field. When the latter is rapidly increased, an instability occurs: the walls between cells undulate. Such an instability has als o been observed in other 2D cellular structures, which exist for insta nce in Langmuir monolayers or in magnetic garnets thin films. In this paper we give a theoretical analysis of this instability, the issues o f which are shown to be well confirmed by experiments and numerical si mulations.