Solving the Solar Dynamo Problem
Hannah Schunker

The solar dynamo problem is one of the enduring problems in solar physics, and in the current technological age it is becoming more pressing to solve it. Solar dynamo theory emphasizes two key processes: the creation of toroidal field by the winding up of poloidal field and the generation of poloidal field from the Coriolis force acting on emerging toroidal field. These two processes form a cycle. Our statistical analysis of hundreds of active regions points to convection playing an important role in the active region emergence process. These results challenge the long-standing model of flux tubes rising freely from the base of the convection zone through the convection layer towards the surface. These flux tubes are thought to originate in the toroidal field at the base of the convection zone where there is a radial shear in the Sun's rotation rate. One difficulty is that we only have one star where we can resolve the interior radial shear: the Sun. Recently, exquisite observations from NASA's Kepler mission has made it possible to probe the interior dynamics of distant stars using asteroseismology. We are developing methods to measure the interior radial differential rotation of other Sun-like stars to constrain the importance of this shear layer for generating solar-like activity cycles. Understanding the physics behind these two key processes will allow us to make significant progress towards constraining models of the solar dynamo.