Constraining the amplitude of turbulence in solar corona using   observations of angular broadening of radio sources
  The angular broadening of compact radio sources observed through a medium having turbulent density irregularities is usually estimated using the phase structure function. We employ an exact formulation for the phase structure function that helps in obtaining an accurate estimate of angular broadening when the baseline lengths are comparable to the inner scale of the turbulent spectrum. 
Madhusudan Ingale, Prasad Subramanian, Iver H. Cairns
astro-ph.SR