Magnetic-drift processes in differentially rotating turbulence

The mean electromotive force is considered in a differentially rotating flu id taking into account stretching of the turbulent magnetic field. Calculat ions are performed by making use of the second order correlation approximat ion. Nonuniformity of the angular velocity leads to specific drift processe s in the azimuthal direction. Due to this drift the magnetic field can rota te with a somewhat different angular velocity than the fluid. Differential rotation can also lead in a new instability of a non-axisymmetric mean held . Regardless of the law of the differential rotation this instability can r esult in an exponential amplification of the field.