Cycling Changes in the Amplitudes of the 27-Day
Variation of the Galactic Cosmic Ray Intensity
A. Gil · M.V. Alania
We study quasi-periodical changes in the amplitudes of the 27-day variation of the
galactic cosmic ray (GCR) intensity, and the parameters of solar wind and solar activity.We
have recently found quasi-periodicity of three to four Carrington rotation periods (3 – 4 CRP)
in the amplitudes of the 27-day variation of the GCR intensity (Gil and Alania in J. Atmos.
Solar-Terr. Phys. 73, 294, 2011). A similar recurrence is recognized in parameters of solar
activity (sunspot number, solar radio flux) and solar wind (components of the interplanetary
magnetic field, solar wind velocity). We believe that the 3 – 4 CRP periodicity, among other
periodicities, observed in the amplitudes of the 27-day variation of the GCR intensity is
caused by a specific cycling structure of the Sun’s magnetic field, which may originate from
the turbulent nature of the solar dynamo.
The full paper is available free here:
I thought it worth flagging this one up, as the periodicity is close to the Mercury orbital period.