Solar Magnetoconvection and Small-Scale Dynamo

Solar Small-scale Magnetoconvection

Magnetoconvection simulations on mesogranule and granule scales near the solar surface are used to study the effect of convective motions on magnetic fields: the sweeping of magnetic flux into downflow lanes, the twisting of magnetic field lines, and the emergence and disappearance of magnetic flux tubes. Fromweak seed fields, convective motions produce highly intermittent magnetic fields in th...

Small-Scale-Field Dynamo.

Small-Scale Turbulent Dynamo

Kinematic dynamo theory is presented here for turbulent conductive fluids. We describe how inhomogeneous magnetic fluctuations are generated below the viscous scale of turbulence where the spatial smoothness of the velocity permits a systematic analysis of the Lagrangian path dynamics. We find analytically the moments and multipoint correlation functions of the magnetic field at small yet finit...

Universal nonlinear small-scale dynamo.

We consider astrophysically relevant nonlinear MHD dynamo at large Reynolds numbers (Re). We argue that it is universal in a sense that magnetic energy grows at a rate which is a constant fraction C(E) of the total turbulent dissipation rate. On the basis of locality bounds we claim that this "efficiency of the small-scale dynamo", C(E), is a true constant for large Re and is determined only by...

The problem of small and large scale fields in the solar dynamo

Three closely related stumbling blocks of solar mean field dynamo theory are discussed: how dominant are the small scale fields, how is the alpha effect quenched, and whether magnetic and current helicity fluxes alleviate the quenching? It is shown that even at the largest currently available resolution there is no clear evidence of power law scaling of the magnetic and kinetic energy spectra i...