2024/07/02 by Nannan Yue, Yue, Nannan, Lile Wang +7 · 1 citation
Engineering · Mathematics · Physics and Astronomy · #Advanced Thermodynamics and Statistical Mechanics #Astrophysics of Galaxies (astro-ph.GA) #FOS: Physical sciences #Fluid Dynamics and Turbulent Flows #Gas Dynamics and Kinetic Theory #Solar and Stellar Astrophysics (astro-ph.SR)
paper · pdf · doi:10.48550/arxiv.2407.02306
openalex publication_date 2024/07/02 · openalex created_date 2024/07/06 · openalex updated_date 2026/07/28
Turbulent diffuse molecular clouds can exhibit complicated morphologies caused by the interactions among radiation, chemistry, fluids, and fields. We performed full 3D simulations for turbulent diffuse molecular interstellar media, featuring time-dependent non-equilibrium thermochemistry co-evolved with magnetohydrodynamics (MHD). Simulation results exhibit the relative abundances of key chemical species (e.g., C, CO, OH) vary by more than one order of magnitude for the "premature" epoch of chemical evolution (t\lesssim 2× 105~\rm yr). Various simulations are also conducted to study the impacts of physical parameters. Non-ideal MHD effects are essential in shaping the behavior of gases, and strong magnetic fields (∼ 10~μ\rm G) tend to inhibit vigorous compressions and thus reduce the fraction of warm gases (T\gtrsim 102~\rm K). Thermodynamical and chemical conditions of the gas are sensitive to modulation by dynamic conditions, especially the energy injection by turbulence. Chemical features, including ionization (cosmic ray and diffuse interstellar radiation), would not directly affect the turbulence power spectra. Nonetheless, their effects are prominent in the distribution profiles of temperatures and gas densities. Comprehensive observations are necessary and useful to eliminate the degeneracies of physical parameters and constrain the properties of diffuse molecular clouds with confidence.