Journal ArticleDOI
Kinematic dynamo problem in a linear velocity field
Reads0
Chats0
TLDR
In this article, it was shown that a magnetic field is asymptotically (t → ∞) decaying in a flow of finite conductivity with v = Cr, where C = Cζ(t) is a random matrix.Abstract:
A magnetic field is shown to be asymptotically (t → ∞) decaying in a flow of finite conductivity with v = Cr, where C = Cζ(t) is a random matrix. The decay is exponential, and its rate does not depend on the conductivity. However, the magnetic energy increases exponentially owing to growth of the domain occupied by the field. The spatial distribution of the magnetic field is a set of thin ropes and (or) layers.read more
Citations
More filters
Journal ArticleDOI
Generalized Stability Theory. Part II: Nonautonomous Operators
TL;DR: In this paper, an extension of classical stability theory to address the stability of perturbations to time-dependent systems is described, where nonnormality is found to play a central role in determining the stability.
Journal ArticleDOI
Simulations of the Small-Scale Turbulent Dynamo
Alexander Schekochihin,Alexander Schekochihin,Steven Cowley,Steven Cowley,S. F. Taylor,S. F. Taylor,J. L. Maron,J. L. Maron,James C. McWilliams +8 more
TL;DR: In this article, an analytical model of saturation based on the idea of partial two-dimensionalization of the velocity gradients with respect to the local direction of the magnetic folds is proposed.
Journal ArticleDOI
Fluctuation dynamo and turbulent induction at low magnetic Prandtl numbers
Alexander Schekochihin,Alexander Schekochihin,Alexey B. Iskakov,Steven Cowley,Steven Cowley,James C. McWilliams,Michael R. E. Proctor,Tarek A. Yousef +7 more
TL;DR: In this paper, a detailed report on a program of direct numerical simulations of incompressible nonhelical randomly forced magnetohydrodynamic (MHD) turbulence that are used to settle a long-standing issue in the turbulent dynamo theory and demonstrate that the fluctuation dynamo exists in the limit of large magnetic Reynolds number Rm 1 and small magnetic Prandtl number Pm 1.
Journal ArticleDOI
Turbulence, magnetic fields, and plasma physics in clusters of galaxies
TL;DR: In this article, it is suggested that the saturated state of the cluster turbulence is a combination of the conventional isotropic magnetohydrodynamic turbulence, characterized by folded, direction-reversing magnetic fields and an Alfven-wave cascade at collisionless scales.
Journal ArticleDOI
Current Status of Turbulent Dynamo Theory. From Large-Scale to Small-Scale Dynamos
TL;DR: In this paper, high resolution simulations of small-scale and large-scale dynamo action in periodic domains are compared with each other and contrasted with similar results at low magnetic Prandtl numbers.
References
More filters
Journal ArticleDOI
Small-scale variation of convected quantities like temperature in turbulent fluid Part 1. General discussion and the case of small conductivity
TL;DR: In this article, a theoretical investigation of the spectrum of a turbulent fluid at large wave-numbers is presented, taking into account the two effects of convection with the fluid and molecular diffusion with diffusivity k. Hypotheses of the kind made by Kolmogoroff for the small-scale variations of velocity in a turbulent motion at high Reynolds number are assumed to apply also to small-size variations of θ.
Journal ArticleDOI
Noncommuting random products
TL;DR: In this paper, the authors consider the problem of determining the asymptotic behavior of a random sequence (i.e., a sequence of independent real valued random variables with a common distribution function) satisfying the strong law of large numbers.
Journal ArticleDOI
The Diffusion of Heat Spots in Isotropic Turbulence
TL;DR: In this paper, a technique has been developed for the production of small heat spots in the turbulent flow behind bi-plane square-mesh grids, and their distribution downstream of the point of production has been studied using a Wollaston wire-resistance thermometer of response time 0$\cdot $0002 sec.
Journal ArticleDOI
On the fine-scale structure of vector fields convected by a turbulent fluid
TL;DR: In this article, a theory of Batchelor's in terms of Eulerian correlations for the distribution of θ for the case when λ [Lt ] v is extended and applied to the vector fields, thereby giving equations for the covariance tensors of F and G appropriate for separations less than $(v^3|\epsilon)^{\frac {1}{4}}$.