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Title: Coherent nonhelical shear dynamos driven by magnetic fluctuations at low Reynolds numbers

Nonhelical shear dynamos are studied with a particular focus on the possibility of coherent dynamo action. The primary results—serving as a follow up to the results of Squire & Bhattacharjee—pertain to the "magnetic shear-current effect" as a viable mechanism to drive large-scale magnetic field generation. This effect raises the interesting possibility that the saturated state of the small-scale dynamo could drive large-scale dynamo action, and is likely to be important in the unstratified regions of accretion disk turbulence. In this paper, the effect is studied at low Reynolds numbers, removing the complications of small-scale dynamo excitation and aiding analysis by enabling the use of quasi-linear statistical simulation methods. In addition to the magnetically driven dynamo, new results on the kinematic nonhelical shear dynamo are presented. Furthermore, these illustrate the relationship between coherent and incoherent driving in such dynamos, demonstrating the importance of rotation in determining the relative dominance of each mechanism.
Authors:
 [1] ;  [2]
  1. Princeton Univ., Princeton, NJ (United States); California Institute of Technology, Pasadena, CA (United States)
  2. Princeton Univ., Princeton, NJ (United States)
Publication Date:
OSTI Identifier:
1254733
Report Number(s):
PPPL--5154
Journal ID: ISSN 1538-4357
Grant/Contract Number:
AC02-09CH11466
Type:
Accepted Manuscript
Journal Name:
The Astrophysical Journal
Additional Journal Information:
Journal Volume: 813; Journal Issue: 1; Journal ID: ISSN 1538-4357
Publisher:
Institute of Physics (IOP)
Research Org:
Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States)
Sponsoring Org:
USDOE
Contributing Orgs:
Max Planck/Princeton Center for Plasma Physics, Department of Astrophysical Sciences and Princeton Plasma Physics Laboratory, Princeton University, Princeton, NJ 08543, USA; TAPIR, California Institute of Technology, Mailcode 350-17, Pasadena, CA 91125, USA
Country of Publication:
United States
Language:
English
Subject:
79 ASTRONOMY AND ASTROPHYSICS accretion, accretion disks; dynamo; magnetic fields; magnetohydrodynamics (MHD); turbulence