The dynamics of the propagating chemical fronts in the autocatalytic reaction A+2B --> 3B are investigated in these films. If the system is started with species A (fuel) in one half and species B (autocatalyst) in the other, the chemical chemical reaction produces a propagating front where B consumes the fuel A. If the diffusion coefficient of A is sufficiently larger than that of B the front will undergo a transverse instability and no longer remain planar.
The first clip shows the front dynamics relatively close to, but beyond, the instability point. One sees a complicated front dynamics where extrema in the front move, collide and coalesce. New extrema are born to maintain the structure. The dynamics may be analysed in terms of the Kuramoto-Sivashinsky equation.
The second clip shows the front dynamics for diffusion ratios far beyond the onset of the instability. Here a new type of dynamics is seen where there are structures with both large and small length scales.
A. Malevanets, A. Careta and R. Kapral, "Biscale chaos in propagating fronts", Phys. Rev. E, 52, 4724 (1995).