On the resonance of galactic dynamos with density waves

Michał Hanasz, Masashi Chiba

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

The coupling between dynamo and density waves in galaxies is reinvestigated analytically and numerically. Applying the method of multiple time-scales to the marginal state of the disc dynamo, we derive an expression for the additional growth rate of the magnetic field as a result of coupling. It is shown that the first-order resonance in the density wave perturbation σ/σ0, and thus the occurrence of linear swing excitation, is possible. Moreover, the final linear growth rate of the magnetic field is always positive, and does not depend on the initial phase difference between the density wave and the magnetic field wave. Both the numerical and the analytical calculations show that ω =2ω0(ω = density wave frequency; ω0 = dynamo frequency) is still the best condition for resonance, due to the above linear effect of swing excitation.

Original languageEnglish
Pages (from-to)545-554
Number of pages10
JournalMonthly Notices of the Royal Astronomical Society
Volume266
Issue number3
DOIs
Publication statusPublished - 1994 Jan 1

Keywords

  • Galaxies: kinematics and dynamics
  • Galaxies: magnetic fields
  • Galaxies: structure
  • MHD
  • Magnetic fields

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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