Gnevyshev peaks in geomagnetic indices

Sunspots have a major 11-year cycle, but the years near the maximum show two or more peaks called Gnevyshev peaks. It was noticed that in cycle 23, the double peaks in sunspot numbers are reflected in the electromagnetic radiations and coronal mass ejections (CMEs) in the solar atmosphere. But, in the interplanetary space, the ICMEs (interplanetary CMEs) show peaks not all coinciding with the peaks of sunspot numbers. Also, there are stream interaction regions (SIR), including co-rotating interaction regions (CIR), which evolve quite differently from sunspot numbers. In the geomagnetic indices, the peaks are related mainly to the peaks in SIRs, indicating that geomagnetic indices have no direct relationship with most of the phenomena at the Sun but are responding only to the interplanetary blobs due to SIRs, which are more predominant in the declining phase of sunspot activity.