Nonlinear feedback during growth of instability of monoenergetic quasi-neutral electron beam

The problem on stability of propagation of one-dimensional neutralized monoenergetic electron beam in a drift space between planar electrodes is considered. It is shown that in case of a strong subcriticality in the above beam an instability, the increment of which does not depend of the system length, is developed. It is suggested that the feedback mechanism is a nonlinear consequence of finite amplitude of initial disturbances