Estimations and Scaling Laws for Stellar Magnetic Fields

In rapidly rotating turbulence (i.e., a Rossby number much less than unity), the standard mixing length theory for turbulent convection breaks down. However, the Coriolis force enters the force balance such that the magnetic field eventually depends on rotation. By simplifying the self-sustained magnetohydrodynamics dynamo equations of electrically conducting fluid motion, with the aid of the theory of isotropic nonrotating or anisotropic rotating turbulence driven by thermal convection, we make estimations and derive scaling laws for stellar magnetic fields with slow and fast rotation. Our scaling laws are in good agreement with the observations.