Pattern formation fueled by dissipation of chemical energy: Conclusive evidence for the formation of a convective torus

An exothermic, autocatalytic chemical reaction can produce a lateral instability which can result in a rapidly moving wave of chemical reactivity. The propagating wave is strongly influenced by thermocapillary effects. At high Marangoni numbers the traveling wave has shown irregular patterning and spatiotemporal irregularity that is aligned in the direction of wave propagation. At lower Marangoni numbers effective coupling occurs between thermocapilary and thermogravitational Rayleigh-Benard type effects. This coupling has produced powerful thermal plumes just behind the leading wave front as well as a series of concentric patterning that represent "transient" Turing patterns. Observations of these effects had led to the conjecture that the wave forms a series of convective tori as it propagates. In this paper recent experimental data are produced that clearly show the dynamic formation of convective tori at the wave front.