Cosmic ray intensity waves and the north-south anisotropy

The 27-day waves that have been observed in north-south asymmetry confirm current understanding of the dependence of the maxima and minima of the asymmetry on IMF sector polarity. The 27-day isotropic waves to which attention is presently given are in phase with the waves of north-south asymmetry, and appear to have a flat rigidity spectrum. They also seem to be reinforcing the waves of north-south asymmetry, most significantly over the weeks that preceded the July, 1982 Forbush decrease, when the neutron intensity was relatively undisturbed.