Beginning with the comment of S. Marinov (Nuovo Cimento C, 19 (1966) 215) article, we studied two processes that could generate a dipolar magnetic field: the electron inertia in metals and the Barnett effect, and calculated the field
generated by such processes. Then, we solved analytically the hydrodynamic problem of the fluid motion in the spherical shell when the inner and outer spheres rotate with different angular velocities and considered an analogue model for the liquid outer core of the Earth. Putting this solution into the kinematics equation of the dynamo theory, we discussed about its solution and about the possibility of modifying and amplifying the dipolar field by the fluid motion
