Three cycle quasiperiodicity in solar wind from polar coronal holes and the size of solar activity cycle 23

The planetary index Ap (designed by Bartels) is an excellent measure of the geo-effectiveness of the solar wind carrying the in situ polar magnetic field from the coronal holes during the declining phase of a solar cycle. It is believed to carry a precursor physical signature of the activity to follow in the new solar cycle. An implied physical understanding invokes poloidal field near sunspot minimum emerging as the toroidal field on the opposite sides of the helioequator as envisaged by Babcock. We have reviewed the entire Ap data in existence. This has led the discovery of a three cycle quasi-periodicity in them. It is present in other datasets as well, back to circa 700 B.C. A new cycle may have started after 1996. The base level of Ap undergoes a sawtooth-like cyclical behavior, very much like a relaxation oscillation, which may result from a non-linear physical process operating at high hello-latitudes outside or inside the sun. The annual mean value of Ap one year into the onset of a new solar cycle appears to forecast its size with high precision. We predict a moderate cycle 23 with a smoothed SSN at its maximum: 131.5+33/-20.