The region of instability for planar reaction fronts of cubic autocatalysis
between ionic species under constant electric field has been determined ac
curately. The ratio of diffusion coefficients at the onset of instability d
elta(cr) is substantially varied by the component-dependent drift and direc
tly proportional to the concentration of the autocatalyst behind the front
beta(s) as delta(cr)=2.3002 beta(s). This opens the possibility to use elec
tric field as a control parameter for reaction-front instabilities. The dis
persion relation calculated from the linear stability analysis of the full
system is in good agreement with the initial evolution of the Fourier modes
associated with the slightly perturbed planar reaction front obtained by t
he direct integration of the governing equations in two spatial dimensions.
(C) 1999 American Institute of Physics. [S0021-9606(99)50148-7].