This article from NASA is worth reading. Our satellites can determine the polarization of light from different parts of the Sun and figure out what the overall magnetic field direction is in different places. And, over time, it changes. It looks like bands form at high latitudes and migrate to the equator in about a 19-year cycle. In addition they have a new aspect of the Sun to monitor: "They noticed that ubiquitous spots of extreme ultraviolet and X-ray light, known as brightpoints, prefer to hover around the vertices of these large areas, dubbed “g-nodes” because of their giant scale." Mapping the behavior of these and of the magnetic bands suggests that the 11-year sunspot cycle is a side effect of the larger cycles.
The exact mechanism isn't clear (at least to me, and I think to them also), but finding new patterns like this is what scientists dream about. The equator, when those vast bands cancel, just has to have some wild magnetohydrodynamics going on...
And no, I didn't know that sunspots migrated to the equator.
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