Nonlinear Ionization Waves

A nonlinear ionization wave equation is derived including a nonlinear form of the ionization rate, instead of a corresponding linear term, in the equation of Pekárek and Krei?í. The nonlinear response of an unstable positive column to a weak pulse disturbance is then numerically calculated in order to study the transition from the linear to the nonlinear wave of stratification. The solutions obtained reproduce some well known features of nonlinear ionization waves.