Poster abstract

Anisotropy and magnetic quenching in center-imposed vertical field magnetoconvection
Ivanovski, S.; Rüdiger, G.; Giesecke, A.


In order to model the magnetoconvection in sunspots the transition from 3D to 2D turbulence under the influence of strong magnetic fields is simulated. The simulations are done in a box heated from below under the presence of a rather week density stratification. The idea is that the vertical central magnetic field of sunspots,imitating the physical situation of strongly confined flux tubes, produces highly anisotropic types of turbulence with strong suppression of the vertical turbulence intensity. The magnetic energy is stronger quenched than the turbulent velocity and its quenching profile keeps stronger vanishing for higher magnetic Prandtl numbers. Magnetic energy shows Rm-dependence (catastrophic) quenching and rather no dependence on Pm. The 3D simulations confirm steady-state saturation of the fluctuating field, determined by
equipartition with the turbulent kinetic energy, independent of the magnetic field or magnetic Reynolds number for large non-helical systems (Blackman & Field, 2005)