Our aim is to study the generation mechanisms of magnetic field on geodynamo models. In that sense, the mean field dynamo theory has proved to be a useful tool in the comprehension of these processes. We propose a model with a ring of vortexes as have been observed in studies of fluid motion in the earth's core. Using the mean field concept we calculate analytically, for the proposed model, the mean electromotive force and the alpha tensor in the stationary case without mean flow. Our calculation relies on the second order correlation approximation.