Excitation
Depending on the structure of the flow, the dynamo may be self-exciting and stable, self-exciting and chaotic, or decaying. The Sun's dynamo is self-exciting: the direction of the field reverses itself about every 11 years, causing the sunspot cycle as ropes of magnetic field lines rise to the surface of the Sun and manifest as sunspots on the surface. The solar dynamo is thought to be located at the tachocline, a region inside the Sun that exhibits a very large shear profile.
Read more about this topic: Solar Dynamo