title: Influence of turbulence on the dynamo threshold.
abstract: We use direct and stochastic numerical simulations of the magnetohydrodynamic equations to explore the influence of turbulence on the dynamo threshold. In the spirit of the Kraichnan-Kazantsev model, we model the turbulence by a noise, with given amplitude, injection scale, and correlation time. The addition of a stochastic noise to the mean velocity significantly alters the dynamo threshold and increases it for any noise at large scale. For small-scale noise, the result depends on its correlation time and on the magnetic Prandtl number.
authors.affiliation: Laboratoire de Mécanique de Lille, CNRS, UMR 8107, Boulevard Paul Langevin, F-59655 Villeneuve d'Ascq Cedex, France.
authors.forename: J-P
authors.initials: JP
authors.lastname: Laval
authors.forename: P
authors.initials: P
authors.lastname: Blaineau
authors.forename: N
authors.initials: N
authors.lastname: Leprovost
authors.forename: B
authors.initials: B
authors.lastname: Dubrulle
authors.forename: F
authors.initials: F
authors.lastname: Daviaud