Repository logo

Infoscience

  • English
  • French
Log In
Logo EPFL, École polytechnique fédérale de Lausanne

Infoscience

  • English
  • French
Log In
  1. Home
  2. Academic and Research Output
  3. Journal articles
  4. Dynamo instabilities in plasmas with inhomogeneous chiral chemical potential
 
research article

Dynamo instabilities in plasmas with inhomogeneous chiral chemical potential

Schober, Jennifer  
•
Rogachevskii, Igor
•
Brandenburg, Axel
February 9, 2022
Physical Review D

We study the dynamics of magnetic fields in chiral magnetohydrodynamics, which takes into account the effects of an additional electric current related to the chiral magnetic effect in high-energy plasmas. We perform direct numerical simulations, considering weak seed magnetic fields and inhomogeneities of the chiral chemical potential mu(5) with a zero mean. We demonstrate that a small-scale chiral dynamo can occur in such plasmas if fluctuations of mu(5) are correlated on length scales that are much larger than the scale on which the dynamo growth rate reaches its maximum. Magnetic fluctuations grow by many orders of magnitude due to the small-scale chiral dynamo instability. Once the nonlinear backreaction of the generated magnetic field on fluctuations of mu(5) sets in, the ratio of these scales decreases and the dynamo saturates. When magnetic fluctuations grow sufficiently to drive turbulence via the Lorentz force before reaching maximum field strength, an additional mean-field dynamo phase is identified. The mean magnetic field grows on a scale that is larger than the integral scale of turbulence after the amplification of the fluctuating component saturates. The growth rate of the mean magnetic field is caused by a magnetic alpha effect that is proportional to the current helicity. With the onset of turbulence, the power spectrum of mu(5) develops a universal k(-1) scaling independently of its initial shape, while the magnetic energy spectrum approaches a k(-3) scaling.

  • Details
  • Metrics
Type
research article
DOI
10.1103/PhysRevD.105.043507
Web of Science ID

WOS:000754626800007

Author(s)
Schober, Jennifer  
Rogachevskii, Igor
Brandenburg, Axel
Date Issued

2022-02-09

Publisher

American Physical Society

Published in
Physical Review D
Volume

105

Issue

4

Article Number

043507

Subjects

Astronomy & Astrophysics

•

Physics, Particles & Fields

•

Physics

•

magnetic-fields

•

collisions

•

turbulence

Editorial or Peer reviewed

REVIEWED

Written at

EPFL

EPFL units
LASTRO  
Available on Infoscience
March 14, 2022
Use this identifier to reference this record
https://infoscience.epfl.ch/handle/20.500.14299/186389
Logo EPFL, École polytechnique fédérale de Lausanne
  • Contact
  • infoscience@epfl.ch

  • Follow us on Facebook
  • Follow us on Instagram
  • Follow us on LinkedIn
  • Follow us on X
  • Follow us on Youtube
AccessibilityLegal noticePrivacy policyCookie settingsEnd User AgreementGet helpFeedback

Infoscience is a service managed and provided by the Library and IT Services of EPFL. © EPFL, tous droits réservés