High field strength modified ABC and rotor dynamos

Abstract

The Archontis dynamo was the first stationary dynamo discovered which saturates with almost equal magnetic and kinetic energies in the limit of large Reynolds numbers. In this paper we present two further examples, one based on a series of numerical calculations and the other on the analytic rotor dynamos of Herzenberg. The forcing and flow in these new examples lack some of the symmetries of the Archontis dynamo are therefore more generic. The saturation mechanism is thus not a unique property of the Archontis dynamo. For the numerical solutions, we also have investigated the structure and stability of the flow and field near the stagnation points and those streamlines which enter and leave them. These structures play an important part in the operation of the dynamo mechanism, and the way they interact with one another is mirrored in the analytic example based on the Herzenberg rotors. © 2006 RAS.