Structure of Small-Scale Magnetic Fields in the Kinematic Dynamo Theory

Details Structure of Small-Scale Magnetic Fields in the Kinematic Dynamo Theory Structure of Small-Scale Magnetic Fields in the Kinematic Dynamo Theory

2001-05-18

arxiv.org/abs/astro-ph/0105322v3

Phys.Rev.E65:016305,2002

Astronomy and Astrophysics

Astrophysics

revtex, 21 pages, 6 figures, 2 tables; this is the final version of the paper as published in PRE

Scientific paper

10.1103/PhysRevE.65.016305

A weak fluctuating magnetic field embedded into a turbulent conducting medium grows exponentially while its characteristic scale decays. In the ISM and protogalactic plasmas, the magnetic Pr is very large, so a broad spectrum of growing magnetic fluctuations is excited at subviscous scales. We study the statistical correlations that are set up in the field pattern and show that the magnetic-field lines possess a folding structure, where most of the scale decrease is due to rapid transverse field direction reversals, while the scale of the field variation along itself stays approximately constant. Specifically, we find that the field strength and the field-line curvature are anticorrelated, and the curvature possesses a stationary limiting distribution with the bulk located at the values of curvature comparable to the characteristic wave number of the velocity field and a power tail extending to large values of curvature. The regions of large curvature, therefore, occupy only a small fraction of the total volume of the system. Our theoretical results are corroborated by direct numerical simulations. The implication of the folding effect is that the advent of the Lorentz back reaction occurs when the magnetic energy approaches that of the smallest turbulent eddies. Our results also directly apply to the problem of statistical geometry of the material lines in a random flow.

Affiliated with

Also associated with

No associations

Rating

Structure of Small-Scale Magnetic Fields in the Kinematic Dynamo Theory 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 Structure of Small-Scale Magnetic Fields in the Kinematic Dynamo Theory, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Structure of Small-Scale Magnetic Fields in the Kinematic Dynamo Theory will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-197098