Different description levels of chemical wave front and propagation speed selection

The results of stochastic descriptions and microscopic simulations of a che mical wave front propagating into an unstable stationary state are compared to investigate the problem of speed selection. Three different effects, th e space discretization, the mean number of particles in a cell, and the dev iation from equilibrium molecular velocity distribution, are shown to induc e corrections to the propagation speed predicted by a macroscopic continuou s description. The speed correction due to the perturbation of the particle velocity distribution in the presence of a fast reaction is isolated from the other effects. (C) 1999 American Institute of Physics. [S0021-9606(99)5 1636-X].