Аннотация:A model is developed which describes the nonstationary wave processes occurring on
moving and stationary switching fronts in a diffusion active trigger medium. Using this model, an exact expression is obtained for the shape of a stationary switching front (domain wall) and a detailed study is made of the spectrum and shape of the linear fluctuations which lead to the periodic stratification of the front. This mathematical model of a two-dimensional anisotropic medium is based on a system of FitzHugh-Nagumo equations.