Radio-wave propagation through a medium containing electron-density   fluctuations described by an anisotropic Goldreich-Sridhar spectrum
  We study the propagation of radio waves through a medium possessing density fluctuations that are elongated along the ambient magnetic field and described by an anisotropic Goldreich-Sridhar power spectrum. We derive general formulas for the wave phase structure function, visibility, angular broadening, diffraction-pattern length scales, and scintillation time scale for arbitrary distributions of turbulence along the line of sight, and specialize these formulas to idealized cases. 
B. D. G. Chandran and D. C. Backer