Will Solar Cycle 25 Be Shockingly Strong?

EarthSky: New sunspot cycle could be among strongest on record

McIntosh believes the bright points mark the travel of magnetic field bands, which wrap around the sun. When the bands from the northern and southern hemispheres – which have oppositely charged magnetic fields – meet at the equator, they mutually annihilate one another leading to a “terminator” event. These terminators are crucial markers on the sun’s 22-year clock, McIntosh says, because they flag the end of a magnetic cycle, along with its corresponding sunspot cycle, and act as a trigger for the following magnetic cycle to begin.

While one set of oppositely charged bands is about halfway through its migration toward the equatorial meetup, a second set appears at high latitudes and begins its own migration. While these bands appear at high latitudes at a relatively consistent rate – every 11 years – they sometimes slow as they cross the mid-latitudes, which appears to weaken the strength of the upcoming solar cycle.

This happens because the slowdown acts to increase the amount of time that the oppositely charged sets of bands overlap and interfere with one another inside the sun. The slowdown extends the current solar cycle by pushing the terminator event out in time. Shifting the terminator out in time has the effect of eating away at the spot productivity of the next cycle.

The opposite is also true, the Maunder Minimum cycle came after a 15-year solar cycle. Solar Cycle 24 was only 10 years long, so the theory proposes Solar Cycle 25 will be stronger than normal cycles. Most forecasts have predicted a weak cycle.