Numerical study of dynamo action at low magnetic Prandtl numbers

Details Numerical study of dynamo action at low magnetic Prandtl numbers Numerical study of dynamo action at low magnetic Prandtl numbers

2004-10-07

arxiv.org/abs/physics/0410046v1

Physics

Geophysics

4 pages, 4 figures

Scientific paper

10.1103/PhysRevLett.94.164502

We present a three--pronged numerical approach to the dynamo problem at low magnetic Prandtl numbers $P_M$. The difficulty of resolving a large range of scales is circumvented by combining Direct Numerical Simulations, a Lagrangian-averaged model, and Large-Eddy Simulations (LES). 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 $P_M=1$ down to $P_M=10^{-2}$; (ii) the critical magnetic Reynolds number increases sharply with $P_M^{-1}$ as turbulence sets in and then saturates; (iii) in the linear growth phase, the most unstable magnetic modes move to small scales as $P_M$ is decreased and a Kazantsev $k^{3/2}$ spectrum develops; then the dynamo grows at large scales and modifies the turbulent velocity fluctuations.

Affiliated with

Also associated with

No associations

Rating

Numerical study of dynamo action at low magnetic Prandtl numbers does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Numerical study of dynamo action at low magnetic Prandtl numbers, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Numerical study of dynamo action at low magnetic Prandtl numbers will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-216556