Possible explanation of the fine structure of magnetic fields in the Sun

A possibility of pumping of the magnetic field by hydrodynamic motions up to large values of the magnetic force (such that the magnetic energy density exceed that of the kinetic one) is considered. The possibility of such pumping is illustrated by a simple example of Hatmann flow. A stochastic model of pumping for turbulence motion is developed for the case when the magnetic field is amplified by granulation motions. The granules thereby have a short lifetime, the model being thus in agreement with the observations. An estimate for saturation effects, when further amplification of field becomes impossible, is given