Numerical modeling of a small-scale self-interaction of radiation in pulsed CO2 amplifiers

Small-scale distortions are predicted for the initially smooth intensity profile of a laser beam of a pulsed CO₂ amplifier. These distortions are due to a thermal self-interaction and their transverse scale is of the order of several millimeters. Phase modulation of the beam entering the amplifier makes a beam instability more likely. The effect under discussion alters radically the beam structure by splitting it into filaments if the self-interaction is strong.