The subharmonics of the 22-year solar cycle

Summary We briefly discuss the existence in various aspects of solar activity of the precise periodicities of Hale cycle (22y), Gleissberg cycle (88y) and of 132y recently discovered by our group. We consider also the possible harmonics of 11y and 5.5y, and make the hypothesis that the Sun behaves as a nonlinear system forced by an oscillator having the Hale frequency. The frequencies of 1c/88y and of 1c/132y might be two subharmonics of Hale frequency. The forcing elementx inside the Sun might be identified with the torsional oscillator suggested by Bracewell. To speed up publication, the proofs were not sent to the authors and were supervised by the Scientific Committee.