Optimum reduction of the dynamo threshold by a ferromagnetic layer located in the flow

Abstract

We consider a fluid dynamo model generated by the flow on both sides of a moving layer. The magnetic permeability of the layer is larger than that of the flow. We show that there exists an optimum value of magnetic permeability for which the critical magnetic Reynolds number for dynamo onset is smaller than for a nonmagnetic material and also smaller than for a layer of infinite magnetic permeability. We present a mechanism that provides an explanation for recent experimental results. A similar effect occurs when the electrical conductivity of the layer is large.

8 pages, 10figures

References in corpus (3)

• Generation of magnetic field by dynamo action in a turbulent flow of liquid sodium
• On the magnetic fields generated by experimental dynamos
• Impact of impellers on the axisymmetric magnetic mode in the VKS2 dynamo experiment

Cited by in corpus (1)

• Enhanced dynamo growth in nonhomogeneous conducting fluids