Analytical theory of hard excitation in the long-time-interaction O-type resonance oscillator

The conditions under which the hard excitation in 0-type resonance oscillator appears, have been considered previously. This report is devoted to the clarification of the question of applicability of the theory based on the assumption of small value of the dimensionless amplitude of wave field. The problem is solved using traditional methods, but it requires solving the movement equation and consequently a differential equation.