Laser Atmospheric Propagation Kinetics PDF Download

The method of moments is used to define and derive expressions for laser beam deflection and beam radius broadening for high-energy propagation through the Earth s atmosphere. These expressions are augmented with the integral invariants of the corresponding nonlinear parabolic equation that describes the electric field of high-energy laser beam to propagation to yield universal equations for the aforementioned quantities; the beam deflection is a linear function of the propagation distance whereas the beam broadening is a quadratic function of distance. The coefficients of these expressions are then derived from a thin screen approximation solution of the nonlinear parabolic equation to give corresponding analytical expressions for a target located outside the Earth s atmospheric layer. These equations, which are graphically presented for a host of propagation scenarios, as well as the thin screen model, are easily amenable to the phase expansions of the wave front for the specification and design of adaptive optics algorithms to correct for the inherent phase aberrations. This work finds application in, for example, the analysis of beamed energy propulsion for space-based vehicles. Manning, Robert M. Glenn Research Center NASA/TM-2012-217634, E-18279 WBS 439432.04.07.05 METHOD OF MOMENTS; WAVE PROPAGATION; HIGH POWER LASERS; NONLINEAR EQUATIONS; ATMOSPHERIC STRATIFICATION; EARTH ATMOSPHERE; ADAPTIVE OPTICS; POWER BEAMING; ELECTRIC FIELDS