Role of the Hall Current in Magnetohydrodynamic Dynamos

Abstract

A theoretical mean field closure for Hall magnetohydrodynamics (Hall-MHD) is developed to investigate magnetic field generation through dynamo processes in low electron density astrophysical systems. We show that by modifying the dynamics of microscopic flows, the Hall currents could have a profound impact on the generation of macroscopic magnetic fields. As an illustrative example, we show how dynamo waves are modified by the inclusion of Hall currents. By dropping the usual assumption of a correlation time τ for the microscopic dynamics in the mean field dynamos, we find qualitative changes in the growth rate of dynamo modes.