Thermal Self-Action of High-Power Continuous and Pulse-Periodic CO_2 Laser Radiation in Air: I. Numerical Simulation of Propagation along an Atmospheric Path

摘要

A problem of transportation of high-power laser radiation energy at a wavelength of 10.6 μm in the atmosphere is theoretically considered in terms of its thermal and wind nonlinearities. The power char- acteristics of continuous and pulse-periodic radiation are studied during propagation along a surface kilome- ter-long atmospheric path with sharp focusing onto a receiver. Key factors most affecting high-power radia- tion propagation are found. It is ascertained that an undesirable effect of thermal defocusing can be reduced using a train of low-power short pulses with a quite high repetition rate due to the effect of light-induced "blooming" of the gas medium. The questions of scaling optical paths from the viewpoint of their equivalence in manifestation of thermal nonlinearity are discussed.