Measuring the inner scale of atmospheric turbulence by correlation of lateral displacements of thin parallel laser beams

A method of determining the inner scale of atmospheric turbulence is described which is based on a property of the correlation functions of the displacements of thin parallel beams. This method is studied theoretically for the modified von Karman model of the spectrum of refractive index fluctuations, which has both inner and outer scales. Experimental applications of the method to both laboratory generated and outdoor turbulence are described.