Abstract:
Power-spectral analysis of cosmic-ray indices (CRI) data for the years 1989–1991 shows
a 170-day periodicity of cosmic rays. The periodicity is related to a strong magnetic field. Power-
spectral analysis of the long-term periodicity (∼11 years) of the CRI data for the years 1953–
1997 shows that the period 1989 – 1991 is a unique one in the sense of the discussed pronounced
periodicity. The 170-day periodicity of cosmic rays was interpreted in the base of six solar rotations
(1 SR = 28.3-day periodicity of 10.7 cm solar radio flux) and may be connected to the instability of
the solar core.
