D. We, H. Holm-for, . Tufo, N. Uc-boulder, G. Ari et al., CDA-9601817. NSF Grants No. ATM- 0327533 (Dartmouth) and No. CMG-0327888 (NCAR) are acknowledged, thank CNRS Dynamo GdR, INSU/PNST, and PCMI Programs for support . Computer time was provided by NCAR, PSC, UC, NERSC, and IDRIS (CNRS)

H. K. Moffatt, Magnetic Field Generation in Electrically Conducting Fluids, 1978.

N. E. Haugen, A. Brandenburg, and W. Dobler, Simulations of nonhelical hydromagnetic turbulence, Physical Review E, vol.70, issue.1, p.16308, 2004.
DOI : 10.1103/PhysRevE.70.016308

L. Marié, Numerical study of homogeneous dynamo based on experimental von K???rm???n type flows, The European Physical Journal B - Condensed Matter, vol.33, issue.4, p.469, 2003.
DOI : 10.1140/epjb/e2003-00187-2

M. Bourgoin, An iterative study of time independent induction effects in magnetohydrodynamics, Physics of Fluids, vol.16, issue.7, p.2529, 2004.
DOI : 10.1063/1.1739401
URL : https://hal.archives-ouvertes.fr/hal-00492367

D. C. Montgomery and A. Pouquet, An alternative interpretation for the Holm ???alpha model???, Physics of Fluids, vol.14, issue.9, p.3365, 2002.
DOI : 10.1063/1.1501542

S. Y. Chen, A connection between the Camassa???Holm equations and turbulent flows in channels and pipes, Physics of Fluids, vol.11, issue.8, p.2343, 1999.
DOI : 10.1063/1.870096

A. Pouquet, J. Léorat, and U. Frisch, Strong MHD helical turbulence and the nonlinear dynamo effect, Journal of Fluid Mechanics, vol.21, issue.02, pp.321-1089, 1976.
DOI : 10.1063/1.1761412

Y. Ponty, H. Politano, and J. F. Pinton, Simulation of Induction at Low Magnetic Prandtl Number, Physical Review Letters, vol.92, issue.14, p.144503, 2004.
DOI : 10.1103/PhysRevLett.92.144503
URL : https://hal.archives-ouvertes.fr/hal-00163375

J. P. Chollet and M. Lesieur, Parameterization of Small Scales of Three-Dimensional Isotropic Turbulence Utilizing Spectral Closures, Journal of the Atmospheric Sciences, vol.38, issue.12, p.2747, 1981.
DOI : 10.1175/1520-0469(1981)038<2747:POSSOT>2.0.CO;2

U. Müller, R. Stieglitz, and S. Horanyi, A two-scale hydromagnetic dynamo experiment, Journal of Fluid Mechanics, vol.498, p.31, 2004.
DOI : 10.1017/S0022112003006700

F. Pétrélis and S. Fauve, Saturation of the magnetic field above the dynamo threshold, The European Physical Journal B, vol.22, issue.3, p.273, 2001.
DOI : 10.1007/s100510170103