• EN
  • DA

Danish NationalResearch Database

  • Publications
  • Researchers
Example Finds records
water{} containing the word "water".
water supplies"{}" containing the phrase "water supplies".
author:"Doe, John"author:"{}" containing the phrase "Doe, John" in the author field.
title:IEEEtitle:{} containing the word "IEEE" in the title field.
bech{} containing the word "bech".
marie bech"{}" containing the phrase "marie bech".
orcid:0000-0002-5429-5292orcid:{} Having a particular ORCID
Need more help? Advanced search tutorial
  • Selected (0)
  • History

Nonlinear MHD dynamo operating at equipartition

    • Save to Mendeley
    • Export to BibTeX
    • Export to RIS
    • Email citation
Authors:
  • Archontis, V. ;
    Close
    University of St Andrews
  • Dorch, Bertil ;
    Close
    unknown
  • Nordlund, Åke
    Close
    Orcid logo0000-0002-2219-0541
    unknown
DOI:
10.1051/0004-6361:20065087
Abstract:
Context.We present results from non linear MHD dynamo experiments with a three-dimensional steady and smooth flow that drives fast dynamo action in the kinematic regime. In the saturation regime, the system yields strong magnetic fields, which undergo transitions between an energy-equipartition and a turbulent state. The generation and evolution of such strong magnetic fields is relevant for the understanding of dynamo action that occurs in stars and other astrophysical objects. Aims.We study the mode of operation of this dynamo, in the linear and non-linear saturation regimes. We also consider the effect of varying the magnetic and fluid Reymolds number on the non-linear behaviour of the system. Methods.We perform three-dimensional non-linear MHD simulations and visualization using a high resolution numerical scheme. Results.We find that this dynamo has a high growth rate in the linear regime, and that it can saturate at a level significantly higher than intermittent turbulent dynamos, namely at energy equipartition, for high values of the magnetic and fluid Reynolds numbers. The equipartition solution however does not remain time-independent during the simulation but exhibits a much more intricate behaviour than previously thought. There are periods in time where the solution is smooth and close to energy-equipartition and others where it becomes turbulent. Similarities and differences in the way the magnetic field is amplified and sustained for experiments with varying Reynolds numbers are discussed. Conclusions.Strong magnetic fields, in near equipartition, can be generated also by a non-turbulent dynamo. A striking result is that the saturation state of this dynamo reveals interesting transitions between turbulent and laminar states.
Type:
Journal article
Language:
English
Published in:
Astronomy and Astrophysics, 2007, Vol 472, Issue 3, p. 715-726
Keywords:
magnetfelter; magnetohydrodynamik; plasma; turbulens; magnetic fields; magnetohydrodynamics; plasmas; turbulence; Faculty of Science
Main Research Area:
Science/technology
Publication Status:
Published
Review type:
Peer Review
Submission year:
2007
Scientific Level:
Scientific
ID:
7314944

Full text access

  • Doi Get publisher edition via DOI resolver
Checking for on-site access...

On-site access

At institutions

  • Ministry of culture.en
  • Copenhagen university.en
Feedback

Sitemap

  • Search
    • Statistics
    • Tutorial
    • Data
    • FAQ
    • Contact
  • About
    • Institutions
    • Release History
    • Cookies and Personal Data
  • Open Access
    • The Danish Open Access Indicator

Copyright © 1998–2018.

Fivu en