On the Structure of the Magnetic Field in a Kinematic Abc Flow Dynamo

The kinematic induction equation of MHD is solved numerically in the case of the normal \111" ABC ow using a general staggered mesh method. Careful 3-D visualizations of the topology of the magnetic eld reveal that previous conclusions about the modes of operation of this type of kinematic dynamo must be revised. The two known windows of dynamo action at low and high magnetic Reynolds number , correspond to two distinct modes, both relying crucially on the replenishing of the magnetic eld near a discontinuity at the type stagnation points in the ow. One of these modes display double magnetic structures that were previously found only to obscure the physics of the dynamo: They turn out, however, to play an important part in the process of amplifying the magnetic eld. Invariant properties of the mode in the second magnetic Reynolds number window support the case for the normal ABC ow as a fast dynamo.