Electric field effects on BZ chemical waves: Wave annihilation at negative fields

摘要

An asymptotic solution of the Fieldndash;Kouml;rouml;sndash;Noyes (FKN) model of the Belousovndash;Zhabotinskii (BZ) reaction is coupled with electrical conduction and thermal diffusion and the parametric dependence of the wave velocity on the electric field is analyzed. Previous theoretical and experimental evidence has verified the existence of a critical field beyond which the waves are annihilated. Furthermore, theory predicts the existence of a Fisher limiting field at which the HBrO2front of the BZ wave has the form and velocity of a Fisher wave (velocity ge;2 in dimensionless units). In this paper theoretical evidence for a second critical field is presented. The first critical field occurs at a positive field for waves moving in the positive direction; the present result predicts a wave destruction at negative fields beyond the Fisher limiting field. These results correspond to destruction by the catalyst (at positive field) and to destruction by bromide (at negative fields).