Mesoscopic Speckle

We have measured the local and global statistics of singularity velocity, v, and have related these through the spatial correlation function of v. The distribution of v is a mixture of a mesoscopic distribution of global change in the speckle pattern and the distribution for v for Gaussian random fields. When v is normalized by the standard deviation of the fractional intensity change, probability distributions and correlation function of v approach those for random Gaussian fields. These results are directly analogous to the statistics of transmitted intensity normalized by the total transmission and provide a unified framework for understanding statistics of speckle evolution and intensity.