Solar Dud or Doozy?

There is some news in the past few days that the a few new sunspots are appearing, it may be that the next period of solar activity has begun. Will it be a dud or a doozy?

The sun has a quite regular cycle that repeats about every 11.5 years. Each cycle represents a reversal of the the sun's magnetic field -- magnetic north becomes south, south becomes north -- so it actually takes 23 years for the sun's magnetic field structure to return to its starting configuration.

During one of these 11.5 year cycles, the sun's magnetic field gets tangled and wound up in its circulating convective zone, located in the outer third of the sun. Once in a while, the magnetic field pokes out from the beneath the surface, and a sunspot appears. So sunspots are indicators of the how chaotic the magnetic field is within the sun.

Solar activity is a problem for us on the earth since the energetic particles ejected during solar storms can affect communications, power grids and the orbits of satellites. Being able to predict the the solar cycle, both timing and strength, is a valuable tool that can save lives and equipment. Unfortunately, predictions have been more of an art than a science.

I was really intrigued by a presentation at the 2005 AAS conference several years ago by Peter Gilman and Mausumi Dikpati, which claimed an improved method for solar cycle prediction. Their solar model showed that the solar convective zone had large scale circulations, almost like oceanic currents on earth. They also showed that it takes approximately three solar cycles for the solar flows -- which are almost like conveyor belts -- to make one circuit. Thus, they could train a reasonably accurate predictive model, based on the known solar activity from three cycles before (with the added benefit, that it produces predictions for about three cycles into the future as well). Their prediction was that the current solar maximum would be delayed by 6-12 months, but 30-50% more intense than the previous cycle. The "conventional" predictions were calling for the beginning of the cycle to begin in early 2007, while Dikpati and Gilman's group were calling for activity starting in the late 2007 to 2008 time frame.

Well at this stage, it's clear that both the conventional and new Dikpati/Gilman predictions were wrong, since we're past halfway into 2009 before any serious solar activity has appeared. But it's interesting that the onset of the cycle has indeed been delayed from its expected appearance, which indicates that perhaps there is something behind the Dikpati/Gilman model. The "conventional" prediction was recently revised, and now claims that the next cycle will be a dud -- weaker than usual. I've had a little harder time determining if the Dikpati/Gilman group has revised their forecast for the strength of the cycle.

Either way, I think it will be an interesting cycle to watch. I actually hope this solar cycle is an extreme -- either a dud or a doozy -- rather than an average one. Extremes are much better test cases for theories than boring average cases. While I have something to lose if this cycle is a strong one, at least it would be lost in advancement of science.