HALL CURRENT EFFECTS in MEAN-FIELD DYNAMO THEORY

Manasvi Lingam, Amitava Bhattacharjee

Research output: Contribution to journalArticle

7 Scopus citations

Abstract

The role of the Hall term on large-scale dynamo action is investigated by means of the first-order smoothing approximation. It is shown that the standard α coefficient is altered, and is zero when a specific double Beltrami state is attained, in contrast to the Alfvénic state for magnetohydrodynamical dynamos. The β coefficient is no longer positive definite, and thereby enables dynamo action even if α-quenching were to operate. The similarities and differences with the (magnetic) shear-current effect are pointed out, and a mechanism that may be potentially responsible for is advanced. The results are compared against previous studies, and their astrophysical relevance is also highlighted.

Original languageEnglish (US)
Article number51
JournalAstrophysical Journal
Volume829
Issue number1
DOIs
StatePublished - Sep 20 2016

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Keywords

  • ISM: magnetic fields
  • dynamo
  • galaxies: magnetic fields
  • magnetohydrodynamics (MHD)
  • turbulence

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