[en] The subject of these lectures is experimental nonaccelerator neutrino physics. We discuss experiments on solar and atmospheric neutrino flux measurements, as well as experiments devoted to recording the antineutrino on nuclear reactors in the context of determining the parameters of neutrino oscillations. Neutrino geophysics, a new field of science, is overviewed.

[en] Recently Borexino collaboration announced the first direct measurement of the low-energy neutrino flux from the pp-reaction in the Sun. Together with previous measurements of solar neutrino fluxes from ⁷Be, ⁸B and pep reactions the measurement completes the study of the neutrino fluxes from the pp-chain of solar reactions. Technical details of the analysis are presented, and results and implications are discussed. (paper)

[en] The current status of neutrino physics is briefly reviewed, the basic properties of the neutrino are discussed, and the most challenging problems in this rapidly developing field are described. Written to mark the anniversary of the Joint Institute for Nuclear Research, this paper highlights JINR's contributions to the development of neutrino physics and places special emphasis on the prospects of the JINR neutrino program.

[en] New data on solar-neutrino flux measurements are presented, and their compatibility with the Mikheev-Smirnov-Wolfenstein oscillation model is discussed. A review is given to topical problems in low-energy neutrino physics, such as the accurate measurement of the CNO-cycle neutrino flux, which is dictated by the data conflict about the chemical composition of the Sun, and a possibility of neutrino oscillations that do not fit into the three-flavor model.

[en] Neutrino produced in a chain of nuclear reactions in the Sun starting from the fusion of two protons, for the first time has been detected in a real-time detector in spectrometric mode. The unique properties of the Borexino detector provided an oppurtunity to disentangle pp-neutrino spectrum from the background components. A comparison of the total neutrino flux from the Sun with Solar luminosity in photons provides a test of the stability of the Sun on the 10⁵ years time scale, and sets a strong limit on the power production in the unknown energy sources in the Sun of no more than 4% of the total energy production at 90% C.L.

[en] Borexino is continuing to take data and presenting the new results. The most recent Borexino results are discussed and plans for the nearest future are presented.

[en] Measurement of the Solar pp-neutrino flux completed the measurement of Solar neutrino fluxes from the pp-chain of reactions in Borexino experiment. The result is in agreement with the prediction of the Standard Solar Model and the MSW/LMA oscillation scenario. A comparison of the total neutrino flux from the Sun with Solar luminosity in photons provides a test of the stability of the Sun on the 10"5 years time scale, and sets a strong limit on the power production by the unknown energy sources in the Sun. (paper)