Large-scale intermittency of liquid-metal channel flow in a magnetic field

We predict a novel flow regime in liquid metals under the influence of a magnetic field. It is characterised by long periods of nearly steady, two-dimensional flow interrupted by violent three-dimensional bursts. Our prediction has been obtained from direct numerical simulations in a channel geometry at low magnetic Reynolds number and translates into physical parameters which are amenable to experimental verification under laboratory conditions. The new regime occurs in a wide range of parameters and may have implications for metallurgical applications.