Fragmentation of Filamentary Cloud Permeated by Perpendicular Magnetic Field

Abstract

We examine the linear stability of an isothermal filamentary cloud permeated by a perpendicular magnetic field. Our model cloud is assumed to be supported by gas pressure against the self-gravity in the unperturbed state. For simplicity, the density distribution is assumed to be symmetric around the axis. Also for simplicity, the initial magnetic field is assumed to be uniform and turbulence is not taken into account. The perturbation equation is formulated to be an eigenvalue problem. The growth rate is obtained as a function of the wavenumber for fragmentation along the axis and the magnetic field strength. The growth rate depends critically on the outer boundary. If the displacement vanishes in the region very far from the cloud axis (fixed boundary), cloud fragmentation is suppressed by a moderate magnetic field, which means the plasma beta is below 1.67 on the cloud axis. If the displacement is constant along the magnetic field in the region very far from the cloud, the cloud is unstable even when the magnetic field is infinitely strong. The cloud is deformed by circulation in the plane perpendicular to the magnetic field. The unstable mode is not likely to induce dynamical collapse, since it is excited even when the whole cloud is magnetically subcritical. For both the boundary conditions the magnetic field increases the wavelength of the most unstable mode. We find that the magnetic force suppresses compression perpendicular to the magnetic field especially in the region of low density.

arXiv comment15 pages, 13 figures, to appear in the Astrophysical Journal

References in corpus (8)

• Herschel view of the Taurus B211/3 filament and striations: Evidence of filamentary growth?
• The Physics of Star Formation
• Magnetically Regulated Star Formation in 3D: The Case of Taurus Molecular Cloud Complex
• Helical Fields and Filamentary Molecular Clouds II - Axisymmetric Stability and Fragmentation
• Near-Infrared Imaging Polarimetry Toward Serpens South: Revealing the Importance of the Magnetic Field
• Magnetohydrostatic Equilibrium Structure and Mass of Filamentary Isothermal Cloud Threaded by Lateral Magnetic Field
• Filamentary flow and magnetic geometry in evolving cluster-forming molecular cloud clumps
• Structure and Stability of Filamentary Clouds Supported by Lateral Magnetic Field

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