Dynamo Simulations in Solar Convection Zone
Bidya Binay Karak1, Axel Brandenburg1, Petri Käpylä2 and Maarit Käpylä2
1
2
Nordita, Stockholm, Sweden
ReSoLVE Centre of Excellence, Aalto University, Finland
bidyakarak@gmail.com
Realistic direct numerical simulation of solar dynamo is not possible at present due
to extreme parameter conditions in the solar convection zone. However, a significant
progress can be made by performing simulations in local cartesian geometry and by
producing turbulence by a forcing function. By choosing this forcing to be helical and
by imposing a large-scale shear in the simulation box, we can excite the large-scale
dynamo as well as the small-scale dynamo when the fluid is sufficiently random. We
shall show that this kind of simple setup allows us to understand some basic questions
of the solar magnetic field. Later, we shall present some results from rotating globalconvection simulations in the spherical geometry of the solar convection zone. We shall
show that under certrain parameter regimes, these solar-like global simulations are
successful in reproducing only a few basic features of the solar cycle.
This presentation will be based two papers: Karak et al. A&A 576, A26, and
Karak & Brandenburg, ApJ submitted, arXiv:1505.06632.