Cycling Changes in the Amplitudes of the 27-Day Variation of the Galactic Cosmic Ray Intensity

Posted: May 5, 2012 by tallbloke in Astronomy, Astrophysics, cosmic rays, Cycles, Electro-magnetism, Solar physics, solar system dynamics

Cycling Changes in the Amplitudes of the 27-Day
Variation of the Galactic Cosmic Ray Intensity
A. Gil · M.V. Alania

Abstract
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:

http://www.springerlink.com/content/j67150p1m4655626/fulltext.pdf

I thought it worth flagging this one up, as the periodicity is close to the Mercury orbital period.

Here’s fig 2

Comments
  1. vukcevic says:
    May 5, 2012 at 10:10 pm

    This is not a new discovered phenomenon. Our cantankerous Dr. S with his colleagues discovered this nearly 40 years ago. I myself did some work too. Sun has a magnetic bulge at 240 degree solar longitude, when this bulge sweeps the Earth everything heading our way from GCR to Ap is affected.
    http://www.vukcevic.talktalk.net/LFC7.htm
    http://www.leif.org/research/Atlas%20of%20IMF%20Polarity%201947-1975.pdf
    see top of page 2719.
    Jane Feynman (sister of Richard ) wrote a paper too, calling effect ‘solar memory’.
    (Vuk)

  2. Edim says:
    May 6, 2012 at 8:14 am

    Vuk, that sunspot longitudinal distribution is very interesting. Time frame? Does the bulge move?

    The apparent rotation (from the Earth) of the Sun at its equator is about 28 days, I think. A month. Month and Moon are cognates. Interesting that the Moon’s axial tilt with respect to the Ecliptic is almost zero.

  3. vukcevic says:
    May 10, 2012 at 4:53 pm

    Edim
    Svalgaard’s paper
    http://www.leif.org/research/Long-term%20Evolution%20of%20Solar%20Sector%20Structure.pdf