Propagation of High Energy Laser Beams in Various Environments
2007
Sprangle, Phillip | Penano, Joseph | Hafizi, Bahman
We report the results of our theoretical study on the key physical processes that affect the propagation of nigh energy lasers in the atmosphere. The main objective of this study is to discuss the optimum laser wavelength and power for efficient propagation in maritime, desert, rural and urban atmospheric environments. The theoretical/numerical model used in this study includes the effects of aerosol and molecular scattering, aerosol heating and vaporization, thermal blooming due to aerosol and molecular absorption, atmospheric turbulence, and beam quality. These processes are modeled in a fully three-dimensional and time-dependent manner. It is found that aerosol particles are particularly important because they result in laser scattering, absorption and enhanced thermal blooming. In the water vapor transmission windows, the total absorption coefficient driving thermal blooming can be caused mainly by aerosols and not water vapor. In certain maritime environments the deleterious effects of aerosols can be reduced by vaporization. Aerosol particles which cannot be vaporized, such as those Consisting of dust, soot, etc., can significantly increase thermal blooming. The optimum wavelength and power for propagation are found for each atmospheric environment.
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