Time variations of the solar neutrino flux

The Fourier analysis of the argon-37 production rate for runs 18–80 observed in Davis's well-known solar neutrino experiment is presented. The method of Fourier analysis with the unequally-spaced data of Davis and associates is described and the discovered periods are compared with recently published results for the analysis of the data of runs 18–69. The harmonic analysis of the data of runs 18–80 shows time variations of the solar neutrino flux with periods =8.33, 5.26, 2.13, 1.56, 0.83, 0.64, 0.54, and 0.50 yr, respectively, which confirms earlier computations.