Saturation level of turbulence in collapsing gas clouds

Abstract

We investigate the physical mechanism that decides the saturation level of turbulence in collapsing gas clouds. We perform a suite of high-resolution numerical simulations following the collapse of turbulent gas clouds with various effective polytropic exponents ${\gamma }_{\mathrm{eff}}$, initial Mach numbers ${\mathcal{M}}_0$, and initial turbulent seeds. Equating the energy injection rate by gravitational contraction and the dissipation rate of turbulence, we obtain an analytic expression of the saturation level of turbulence, and compare it with the numerical results. Consequently, the numerical results are well described by the analytic model, given that the turbulent driving scale in collapsing gas clouds is one-third of Jeans length of collapsing core. These results indicate that the strength of turbulence at the first core formation in the early universe/present-day star-formation process can be estimated solely by ${\gamma }_{\mathrm{eff}}$.

12 pages, 8 figures, 2 tables, accepted for publication in ApJ

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Cited by in corpus (4)

• Formation of Massive and Wide First-star Binaries in Radiation Hydrodynamics Simulations
• Non-ideal magnetohydrodynamic simulations of the first star formation: the effect of ambipolar diffusion
• Amplification and saturation of turbulent magnetic field in collapsing primordial gas clouds
• Impeding Turbulence Decay in Self-gravitating Cloud Cores