Magnetohydrodynamic simulations of the wiggle instability in spiral galaxies

Minoru Tanaka, Keiichi Wada, Mami MacHida, Ryoji Matsumoto, Shigeki Miyaji

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

We studied the stability of galactic spiral shocks through two dimensional global magnetohydrodynamic simulations. Recently, Wada & Koda (2003) showed, using global hydrodynamic simulations, that galactic gas flows behind a spiral shock becomes unstable against a perturbation parallel to the shock front and form spur-like density structures. They attributed the origin of this wiggle instability to the Kelvin-Helmholtz (K-H) instability triggered by the acceleration of the gas behind the shock. We carried out global simulations including galactic magnetic fields. The initial magnetic field is assumed to be either uniform or purely toroidal. We found that although the magnetic field reduces the growth rate of the K-H instability, wiggle instability develops even in galaxies with μG magnetic fields. We also present the results of local simulations to demonstrate the dependence of the growth rate of the instability with the wavelength. The interval of spurs is determined by the most unstable wavelength of the wiggle instability.

Original languageEnglish
Title of host publicationMAGNETIC FIELDS IN THE UNIVERSE
Subtitle of host publicationFrom Laboratory and Stars to Primordial Structures
Pages792-797
Number of pages6
DOIs
Publication statusPublished - Sep 28 2005
Externally publishedYes
EventMAGNETIC FIELDS IN THE UNIVERSE: From Laboratory and Stars to Primordial Structures - Angra dos Reis, Brazil
Duration: Nov 28 2004Dec 3 2004

Publication series

NameAIP Conference Proceedings
Volume784
ISSN (Print)0094-243X
ISSN (Electronic)1551-7616

Other

OtherMAGNETIC FIELDS IN THE UNIVERSE: From Laboratory and Stars to Primordial Structures
CountryBrazil
CityAngra dos Reis
Period11/28/0412/3/04

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)

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