A generic structure is proposed for rapidly growing magnetic fields in a class of steady, incompressible flows which are everywhere chaotic with positive Liapunov exponent. In such a flow at high magnetic Reynolds number Rm, the magnetic field is approximately aligned everywhere with the dilating direction of the flow, and may have extremely complicated spatial structure. In the limit of infinite Rm, the leading-order growth rate is bounded below by the positive Liapunov exponent of the flow; thus the field is a fast dynamo.
ASJC Scopus subject areas
- General Physics and Astronomy