Parallel Algorithm for Simulation of Fragmentation and Formation of Filamentous Structures in Molecular Clouds

Rybakin, Boris; Смирнов, Н. Н.; Goryachev, Valery

doi:10.1007/978-3-319-55669-7_12

Cited by 3 publications

(1 citation statement)

References 12 publications

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“…Thus, models Uni-0-0 and Tur-0-0 produce filaments that are structurally different: a uniform cloud favours the formation of a filament with a single current sheet while a turbulent cloud produces a filamentary tail filled with several highly-magnetised knots and sub-filaments (at which E m,cloud /E m 0 ∼ 10 2 −10 3 ). Similar structures have been found in purely HD and MHD simulations of shocks interacting with inhomogeneous media, i.e., systems that have more than one cloud (e.g., see Poludnenko et al 2002;Pittard et al 2005;Raga et al 2009;Alūzas et al 2012Alūzas et al , 2014Rybakin, Smirnov & Goryachev 2016).…”

Section: On the Morphology Of Filamentssupporting

confidence: 70%

Filament formation in wind–cloud interactions– II. Clouds with turbulent density, velocity, and magnetic fields

Banda-Barragán

Federrath

Crocker

et al. 2017

Monthly Notices of the Royal Astronomical Society

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We present a set of numerical experiments designed to systematically investigate how turbulence and magnetic fields influence the morphology, energetics, and dynamics of filaments produced in wind-cloud interactions. We cover three-dimensional, magnetohydrodynamic systems of supersonic winds impacting clouds with turbulent density, velocity, and magnetic fields. We find that log-normal density distributions aid shock propagation through clouds, increasing their velocity dispersion and producing filaments with expanded cross sections and highly-magnetised knots and sub-filaments. In self-consistently turbulent scenarios the ratio of filament to initial cloud magnetic energy densities is ∼ 1. The effect of Gaussian velocity fields is bound to the turbulence Mach number: Supersonic velocities trigger a rapid cloud expansion; subsonic velocities only have a minor impact. The role of turbulent magnetic fields depends on their tension and is similar to the effect of radiative losses: the stronger the magnetic field or the softer the gas equation of state, the greater the magnetic shielding at wind-filament interfaces and the suppression of Kelvin-Helmholtz instabilities. Overall, we show that including turbulence and magnetic fields is crucial to understanding cold gas entrainment in multi-phase winds. While cloud porosity and supersonic turbulence enhance the acceleration of clouds, magnetic shielding protects them from ablation and causes Rayleigh-Taylor-driven sub-filamentation. Wind-swept clouds in turbulent models reach distances ∼ 15 − 20 times their core radius and acquire bulk speeds ∼ 0.3 − 0.4 of the wind speed in one cloud-crushing time, which are three times larger than in non-turbulent models. In all simulations the ratio of turbulent magnetic to kinetic energy densities asymptotes at ∼ 0.1 − 0.4, and convergence of all relevant dynamical properties requires at least 64 cells per cloud radius.

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