Modeling turbulent wave-front phase as a fractional Brownian motion: a   new approach
  This paper introduces a general and new formalism to model the turbulent wave-front phase using fractional Brownian motion processes. Moreover, it extends results to non-Kolmogorov turbulence. In particular, generalized expressions for the Strehl ratio and the angle-of-arrival variance are obtained. These are dependent on the dynamic state of the turbulence. 
Dario G. Perez, Luciano Zunino, Mario Garavaglia