Macroscopic effects of the perturbation of the particle velocity distribution in a trigger wave

Departure from the equilibrium particle velocity distribution induced by a chemical reaction is studied in an inhomogeneous chemical bistable system in which a trigger wave can propagate. These nonequilibrium effects influence the speed and shape of the trigger wave propagating between the two stable stationary states. In contrast to the Fisher front, the discretization of the variables and the internal fluctuations do not sensitively modify the macroscopic properties of the trigger wave. Analytical results deduced from the Boltzmann equation agree well with microscopic simulations using Bird's method. Both approaches lead to large relative corrections to the front speed, in particular for parameter values close to that corresponding to a stationary interface between the two stable states.