Wave solutions of semilinear parabolic equations

Interactions of nonlinear waves (kinks) described by semilinear parabolic equations are investigated. Exact two-phase solutions that generalize Newell's solutions are constructed for nonlinearities having the form of a cubic polynomial. An asymptotic solution describing the interaction of kinks propagating in a strip between the roots of the nonlinearity is obtained for the Kolmogorov–Petrovskii–Piskunov–Fisher equation.