Ja. Lockwood et Wr. Webber, A COMPARISON OF COSMIC-RAY INTENSITIES NEAR THE EARTH AT THE SUNSPOT MINIMA IN 1976 AND 1987 AND DURING 1995 AND 1996, J GEO R-S P, 102(A11), 1997, pp. 24221-24228
The cosmic ray proton and helium intensities measured on the IMP space
craft near the Earth from similar to 45 MeV to several hundred MeV in
April 1996 indicate that the intensities have recovered to almost the
same maximum values they had at the last sunspot minimum. The 1996 int
ensities near the Earth are an even closer match to those observed two
11-year cycles earlier in 1976, This confirming evidence of a 22-year
periodicity in the low-energy cosmic ray intensities and spectral sha
pes is attributed to the effects of the difference in the entry of cos
mic rays into the heliosphere as well as their different drift motion
inside the heliosphere as a consequence of the 22-year periodicity in
the solar magnetic field. This observation thus suggests that drifts p
lay a significant role in the cosmic ray modulation process.