Kinetic Energy Decay Rates of Supersonic and Super-Alfvénic Turbulence in Star-Forming Clouds

1997/12/01 by Mordecai-Mark Mac Low, Mordecai‐Mark Mac Low, Ralf S. Klessen +3 · 11 citations
Physics and Astronomy · #Astro and Planetary Science #Astrophysics #Astrophysics and Star Formation Studies #Atomic physics #Classical mechanics #Computational physics #Interstellar medium #Ionosphere and magnetosphere dynamics #Kinetic energy #Mean kinetic temperature #Mechanics #Molecular cloud #Physics #Stars #Supersonic speed #Turbulence #Turbulence kinetic energy #astro-ph #chao-dyn #nlin.CD #physics.flu-dyn

paper · pdf · doi:10.1103/physrevlett.80.2754

Submitted to Phys. Rev. Letters, 29 Nov. 1997. 10 pages, 2 figures, also available from http://www.mpia-hd.mpg.de/theory/preprints.html#maclow

arxiv created 1997/12/01 · openalex publication_date 1998/03/30 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05

Abstract

We compute 3D models of supersonic, sub-Alfv'enic, and super-Alfv'enic decaying turbulence, with an isothermal equation of state appropriate for star-forming interstellar clouds of molecular gas. We find that in 3D the kinetic energy decays as t^\ensuremath-\ensuremathη, with 0.85<\ensuremathη<1.2. In 1D magnetized turbulence actually decays faster than unmagnetized turbulence. We compared different algorithms, and performed resolution studies reaching 256³ zones or 70³ particles. External driving must produce the observed long lifetimes and supersonic motions in molecular clouds, as undriven turbulence decays too fast.

Citations

• Can Nonlinear Hydromagnetic Waves Support a Self-gravitating Cloud?
• Smoothed Particle Hydrodynamics

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