The solar dynamo and its spots

 

Axel Brandenburg (Nordita, Sweden)

 

There is widespread uncertainty about the nature of the global solar dynamo: is it located essentially in the tachocline, in which equatorward meridional circulation transports field toward low latitudes, or is the dynamo a distributed one, as recent global simulations suggest? A proper understanding of solar activity requires a holistic approach in which the formation of active regions, sunspots, and coronal mass ejections are self-consistently included. In the tachocline scenario, the problem is avoided by postulating the existence of thin flux tubes that erupt to the surface and produce bipolar regions, but in the distributed dynamo scenario the large-scale field has a more diffuse nature and there are no extended flux ropes. Active regions would then need to be maintained by local processes.

 

In my talk, I will review both approaches, summarize the state of global dynamo simulations, and their coupling to the Sun's exterior through coronal mass ejections and the magnetized solar wind. Finally, I will review the current state of modeling magnetic flux concentrations as a phenomenon that is not deeply routed, as is commonly assumed.