D321 渦状銀河におけるスパー構造形成の磁気流体数値実験(D-32 宇宙流体(2),一般講演)

概要

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We studied the stability of galactic spiral shocks by two dimensional global magnetohydrodynamic simulations. By carrying out global hydrodynamical simulations, Wada & Koda (2003) showed that galactic gas flows behind the spiral shock become unstable against the perturbation parallel to the shock 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 gas behind the shock. In their simulations, however, the effects of galactic magnetic fields were ignored. Thus we carried out global simulations including galactic magnetic fields. We found that although magnetic field reduces the growth rate of the K-H instability, spur structures develop even in galaxies with μG magnetic fields. We also confirmed the growth of the wiggle instability by local simulations.
日本流体力学会の論文
2004-08-09