title: Generation of Large-Scale Magnetic Fields by Small-Scale Dynamo in Shear Flows.
abstract: We propose a new mechanism for a turbulent mean-field dynamo in which the magnetic fluctuations resulting from a small-scale dynamo drive the generation of large-scale magnetic fields. This is in stark contrast to the common idea that small-scale magnetic fields should be harmful to large-scale dynamo action. These dynamos occur in the presence of a large-scale velocity shear and do not require net helicity, resulting from off-diagonal components of the turbulent resistivity tensor as the magnetic analogue of the "shear-current" effect. Given the inevitable existence of nonhelical small-scale magnetic fields in turbulent plasmas, as well as the generic nature of velocity shear, the suggested mechanism may help explain the generation of large-scale magnetic fields across a wide range of astrophysical objects.
authors.affiliation: Max Planck and Princeton Center for Plasma Physics, Department of Astrophysical Sciences and Princeton Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543, USA.|TAPIR, Mailcode 350-17, California Institute of Technology, Pasadena, California 91125, USA.
authors.forename: J
authors.initials: J
authors.lastname: Squire
authors.affiliation: Max Planck and Princeton Center for Plasma Physics, Department of Astrophysical Sciences and Princeton Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543, USA.
authors.forename: A
authors.initials: A
authors.lastname: Bhattacharjee