On magnetic coupling between the two hemispheres in solar dynamo models

By introducing an asymmetry between the two hemispheres, we study whether the solar dynamo solutions in the two hemispheres remain coupled with each other. Our calculations are based on the solar dynamo code SURYA, which incorporates the helioseismically-determined solar-rotation profile, a Babcock-Leighton alpha effect concentrated near the surface, and a meridional circulation. When the magnetic coupling between the hemispheres is enhanced by either increasing the diffusion or introducing an alpha effect distributed throughout the convection zone, we find that the solutions in the two hemispheres evolve together with a single period even when we make the meridional circulation or the alpha effect different in the two hemispheres. On the other hand, when the hemispheric coupling is weaker for other values of parameters, an asymmetry between the hemispheres can make solutions in the two hemispheres evolve independently with different periods.