ABSTRACT
The stability analyses of a collisionless plasma, electron plasma oscillations in particular, were based on a linearized model. In that description, the wave amplitude continues to grow exponentially, and the analysis eventually ceases to be valid. It is a quite obvious question to ask what sort of mechanism eventually arrests the wave growth. Quasi-linear theory (Drummond & Pines 1964, Bernstein & Engelmann 1966, Vedenov 1968, Stix 1992, Swanson 2003) is one of the models which can answer that question, at least for some cases.
