Turbulent Mixing in the Interstellar Medium -- an application for Lagrangian Tracer Particles

Abstract

We use 3-dimensional numerical simulations of self-gravitating compressible turbulent gas in combination with Lagrangian tracer particles to investigate the mixing process of molecular hydrogen (H2) in interstellar clouds. Tracer particles are used to represent shock-compressed dense gas, which is associated with H2. We deposit tracer particles in regions of density contrast in excess of ten times the mean density. Following their trajectories and using probability distribution functions, we find an upper limit for the mixing timescale of H2, which is of order 0.3 Myr. This is significantly smaller than the lifetime of molecular clouds, which demonstrates the importance of the turbulent mixing of H2 as a preliminary stage to star formation.

10 pages, 5 figures, conference proceedings "Turbulent Mixing and Beyond 2007"

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• Probing the evolution of molecular cloud structure II: From chaos to confinement
• Star Formation in the First Galaxies I: Collapse Delayed by Lyman-Werner Radiation
• Understanding star formation in molecular clouds II. Signatures of gravitational collapse of IRDCs
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• Modeling H2 formation in the turbulent ISM: Solenoidal versus compressive turbulent forcing
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• Primordial Black Holes Formed during Magneto-Hydrodynamic Turbulence in The Early Universe as Dominant Part of Dark Matter