So, there are the three physical effects that can change the neutrino flavor. The first is the vacuum neutrino oscillations. The second effect is due to the fact that a neutrino may possess an anomalous magnetic dipole moment (AMM), which results in an interaction with an external magnetic field. The third is the Mikheyev-Smirnov-Wolfenstein (MSW) effect. Electron neutrinos are produced in the Sun’s core, then they travel 700,000 km along

the solar radius in the medium with variable density and a sufficiently intensive magnetic field. In these conditions at particular values of oscillation parameters (OPs) and AMM, the decrease of electron neutrinos from an initial flux is possible. After leaving from the solar surface the neutrino flux flies 150,000,000 km in a vacuum before it will reach a terrestrial detector. Here, the conversion of the electron neutrinos are also available, thanks to the vacuum oscillations. The solar neutrinos can reach the detector right away during the day or during the night after penetrating the Earth’s interior. In the last case, at the particular values of the OPs, the influence of the Earth’s matter could change the neutrino flavors ratio in the flux. To date, the information concerning the neutrino sector structure may be divided into three parts:

(i) The neutrino oscillations with the solar frequency that give information about ∆m221, θ12 and estimate θ13 as a preliminary. This class includes in its experiments with solar and reactor neutrinos. (ii) The neutrino oscillations with the atmospheric frequency in which the parameters ∆m231, θ23 and θ13 are determined.