The MSW effect in a fluctuating matter density
  We consider the effect on matter-enhanced neutrino flavor transformation of a randomly fluctuating, delta-correlated matter density. The fluctuations will produce a distribution of neutrino survival probabilities. We find the mean and variance of the distribution for the case of solar neutrinos, and discuss the possibility of placing a limit on solar density fluctuations using neutrino data. 
A. B. Balantekin, J. M. Fetter, F. N. Loreti