Laser beam log amplitude temporal scintillation spectrum due to crosswind. Part 1: Theory
Abstract
We derive the temporal spectral density of the logamplitude scintillation of a laser beam due to cross wind. The dependence on the velocity distribution along the propagation axis  magnitude and direction  in relation to the detector position vector in the plane normal to the axis is of main interest in addition to the usual turbulence parameters such as the inner and outer scales. Also studied are the moments of the (normalized) spectral density, which would appear to be less sensitive to these parameters, as providing possible means for monitoring changes in the wind velocity. We begin in Section 2 with a brief review of propagation theory essential for our purposes. The treatment is different from the standard textbook in that we make systematic use of the parabolic approximation of the Helmholtz equation rather than ad hoc arguments for simplification inside the solution integral. The main results, including the spectral density derivation, are in Section 3. Some approximations  which help avoid purely numerical computer evaluation of the integrals and provide some analytical insight  are studied in Section 4.
 Publication:

NASA STI/Recon Technical Report N
 Pub Date:
 September 1994
 Bibcode:
 1994STIN...9524371B
 Keywords:

 Atmospheric Turbulence;
 Cross Flow;
 Electromagnetic Wave Transmission;
 Laser Beams;
 Scintillation;
 Turbulence Effects;
 Velocity Distribution;
 Wind Effects;
 Wind Velocity;
 Approximation;
 Spectrum Analysis;
 Temporal Distribution;
 Wind Direction;
 Wind Velocity Measurement;
 Lasers and Masers