160-min pulsation of the Sun: New observational results

The 1974–1988 Crimean measurements of the solar line-of-sight velocity continue to show the presence of a statistically significant periodicity P ₁ = 160.009 (±) min with an average harmonic amplitude of about 21 cm s^–1. The period is supposed to be that of the global pulsation of the Sun but with a little-known physical mechanism of excitation.The new observations give some evidence for the existence of a second periodicity, P ₁ = 160.014 (±) min. It is hypothesized that the appearance of P ₁ might be a sidelobe mode (of the P ₀-oscillation) induced by rapid rotation of the central solar core.It is also noted that the spacing, in frequency, between P ₀ and P ₁, corresponds to a beat period of 10 ± 3 yr, which happens to be in good agreement with the average duration of the 11 yr cycle of the magnetic activity of the Sun. Accordingly, we suppose that the phase shift of the P ₀-mode between the 1974–1982 and 1986–1988 time intervals reflects a remarkable change of the general magnetic field of the Sun in the course of the 22 yr solar cycle.