Physics of reaction waves

Reaction waves, in which an energy source sustains a wave front, occur in many areas of physics. The most important of them is a solitary wave or autowave, which is described on a coarse scale as a flamon, a surface separating zones. Mathematically, the waves are described by nonlinear transport equations, whose approximate solution gives propagation velocities of interfaces and stability criteria for the wave fronts. The instabilities of the autowave can produce complicated behavior such as periodic waves or spirals in two dimensions. Manifestations of the complex behavior include Gunn domains and cellular front structures. Important parameters that permit one to classify the wave and its stability are the Lewis number and the Zel’dovich number. A reaction wave can also have a more complicated inner structure, with several zones responsible for different physical properties.