Matter-enhanced neutrino oscillations in the quasi-adiabatic limit

We introduce simple analytic expressions for the neutrino survival probability in media valid in the quasi-adiabatic limit. These expressions provide a quick but accurate alternative to numerical solution of the neutrino propagation equations for the Mikheyev–Smirnov–Wolfenstein effect. They can also be used to extract information about the density scale height from the neutrino data. As an example, we present calculations for solar neutrinos.