Matter oscillations: Neutrino transformation in the Sun and regeneration in the Earth

Calculations of neutrino regeneration phenomena in the Earth as well as transformation in the Sun are presented with relevant predictions for several existing and planned neutrino detection experiments. The validity of computational approximations in the solar case is appropriately investigated. Sensitivity of the calculated results to the solar model is noted. Transformation and regeneration phenomena are calculated to result from transmission through the Earth of neutrinos with E(MeV)/Δ$m^2$(${\mathrm{eV}}^2$) in the vicinity of ${10}^6$ to ${10}^7$. As a result, large time-of-night and seasonal variations are predicted for various solar-neutrino experiments in this parameter range. Analogous effects are predicted for terrestrial cosmic-ray and accelerator experiments.