2019ApJ...881...97H

We examine the linear stability of a filamentary cloud permeated by a perpendicular magnetic field. The initial magnetic field is assumed to be uniform and perpendicular to the cloud axis. The model cloud is assumed to have a Plummer-like density profile and to be supported against self-gravity by turbulence. The effects of turbulence are taken into account by enhancing the effective pressure of a low-density gas. We derive the effective pressure as a function of density from the condition of hydrostatic balance. It is shown that the model cloud is more unstable against radial collapse when the radial density slope is shallower. When the magnetic field is relatively weak, radial collapse is suppressed. If the displacement vanishes in a region very far from the cloud axis, the model cloud is stabilized completely by a relatively weak magnetic field. If rearrangement of the magnetic flux tubes is permitted, the model cloud is unstable even when the magnetic field is extremely strong. The stability depends on the outer boundary condition as in the case of an isothermal cloud. The growth rate of the rearrangement mode is smaller when the radial density slope is shallower.