University of Sussex
Browse

File(s) not publicly available

Scaling laws in decaying helical magnetohydrodynamic turbulence

journal contribution
posted on 2023-06-08, 06:51 authored by M Christensson, Mark HindmarshMark Hindmarsh, A Brandenburg
We study the evolution of growth and decay laws for the magnetic field coherence length xi, energy E_M and magnetic helicity H in freely decaying 3D MHD turbulence. We show that with certain assumptions, self-similarity of the magnetic power spectrum alone implies that xi~t^{1/2}. This in turn implies that magnetic helicity decays as H~t^{-2s}, where s=(xi_{diff}/xi_H)^2, in terms of xi_{diff}, the diffusion length scale, and xi_H, a length scale defined from the helicity power spectrum. The relative magnetic helicity remains constant, implying that the magnetic energy decays as E_M~t^{-1/2-2s}. The parameter s is inversely proportional to the magnetic Reynolds number Re_M, which is constant in the self-similar regime.

History

Publication status

  • Published

Journal

Astronomische Nachrichten

ISSN

0004-6337

Issue

6

Volume

326

Page range

393-399

Department affiliated with

  • Physics and Astronomy Publications

Full text available

  • No

Peer reviewed?

  • Yes

Legacy Posted Date

2012-02-06

Usage metrics

    University of Sussex (Publications)

    Categories

    No categories selected

    Exports

    RefWorks
    BibTeX
    Ref. manager
    Endnote
    DataCite
    NLM
    DC