Experimental study of rough spherical Couette flows: Increasing helicity toward a dynamo state

Abstract

Spherical Couette flows in liquid metals are a suitable candidate for generating magnetic dynamo states in the laboratory. However, results in our 3 meter diameter experiment have shown that an enhancement of the flow's helicity is likely required. Previous works suggested roughening the inner sphere boundary by adding baffles in order to achieve these goals. In the present work, we perform hydrodynamic studies of the effect of different baffle designs in a 40 cm water experiment. Results point to one of these models as a promising upgrade that we will use in our 3 m experiment to effectively increase our chances of obtaining dynamo action.