Numerical Study of Dynamo Action at Low Magnetic Prandtl Numbers

Yannick Ponty (1) , Pablo Mininni (2) , David Montgomery (3) , Jean-François Pinton (4) , Hélène Politano (1) , Annick Pouquet (2)

1 CASSIOPEE - Laboratoire de Cosmologie, Astrophysique Stellaire & Solaire, de Planétologie et de Mécanique des Fluides
2 NCAR - National Center for Atmospheric Research [Boulder]
3 Department of Physics and Astronomy [Hanover]
4 Phys-ENS - Laboratoire de Physique de l'ENS Lyon

We present a three-pronged numerical approach to the dynamo problem at low magnetic Prandtl numbers PM . The difficulty of resolving a large range of scales is circumvented by combining direct numerical simulations, a Lagrangian-averaged model and large-eddy simulations. The flow is generated by the Taylor-Green forcing; it combines a well defined structure at large scales and turbulent fluctuations at small scales. Our main findings are (i) dynamos are observed from PM ≈

Keywords: Magnetic fields; Dynamo

Domains: Sciences of the Universe [physics]; Astrophysics [astro-ph]; Physics [physics]; Astrophysics [astro-ph]; Cosmology and Extra-Galactic Astrophysics [astro-ph.CO]

Yannick Ponty, Pablo Mininni, David Montgomery, Jean-François Pinton, Hélène Politano, et al.. Numerical Study of Dynamo Action at Low Magnetic Prandtl Numbers. Physical Review Letters, 2005, 94, pp.164502. ⟨ensl-00180691⟩