Instability of the radiation wavefront in pulsed CO2 amplifiers

A theoretical investigation is reported of the evolution in space and time of a small-scale perturbation against the background of a smooth beam entering a pulsed CO₂ amplifier. The ranges of the transverse frequency, longitudinal coordinate, and time in which the perturbation growth is exponential are determined. It is shown that the wavefront instability can be suppressed by amplification of the main beam and by the attenuation of sound.