论文标题
重力崩溃期间的非绝热湍流驾驶
Non-adiabatic turbulence driving during gravitational collapse
论文作者
论文摘要
我们研究了湍流球芯的临时重力收缩期间的湍流产生。我们将一维动荡速度分散的比率$ g $，$σ_\ mathrm {1d} $与引力速度$ v_g $，然后在A的假设下进行分析估计$ g $，并在重力之间（$ e_g $）之间进行均衡或病毒平衡（$ e_g $） （$ e_ \ mathrm {turb} $）能量和b）从重力到动荡的能量转移的平稳性（意味着$ e_ \ mathrm {turb}/e_g = $ cst）。在电气和病毒案例中，我们发现$ g = \ sqrt {1/3} \ oft0.58 $和$ g = \ sqrt {1/6} \ oft0.41 $;在固定案例中，我们发现$ g = \ langle v_ \ mathrm {rad} \ rangle l_d/（4π\ sqrt {3}ηrv_g）$，其中$η$是效率因子，$ l_d $是the turbulence of Turmection core core core core core core core core core的能量压力。接下来，我们对两种不同分辨率的等温，跨性别湍流核心的prestellar塌陷进行AMR模拟，以及一个非扰动的控制模拟。我们发现，湍流模拟的速度与非扰动的模拟崩溃，因此湍流产生不会显着减慢崩溃的速度。我们还发现，a）模拟接近倒塌和湍流消散的能量注入速率之间的平衡； b）$ g \ of lot-g \ pm0.035 $，接近“病毒”值（湍流为$ \ sim35-40 \％\％$ $ thermal line-lineWidth）; c）注入量表为$ l_d \ lyssim r $，d）“湍流压力” $ρσ_\ mathrm {1d}^2 $ scales as $ \simρ^{1.64} $，显然几乎可以放映。我们建议，如果湍流在产生后立即消散，则湍流速度分散剂的这种缩放率和几乎病毒值可能与未删除的塌陷率核对。
We investigate the generation of turbulence during the prestellar gravitational contraction of a turbulent spherical core. We define the ratio $g$ of the one-dimensional turbulent velocity dispersion, $σ_\mathrm{1D}$ to the gravitational velocity $v_g$, to then analytically estimate $g$ under the assumptions of a) equipartition or virial equilibrium between the gravitational ($E_g$) and turbulent kinetic ($E_\mathrm{turb}$) energies and b) stationarity of transfer from gravitational to turbulent energy (implying $E_\mathrm{turb}/E_g=$cst). In the equipartition and virial cases, we find $g=\sqrt{1/3}\approx0.58$ and $g=\sqrt{1/6}\approx0.41$, respectively; in the stationary case we find $g=\langle v_\mathrm{rad}\rangle L_d/(4π\sqrt{3}ηRv_g)$, where $η$ is an efficiency factor, $L_d$ is the energy injection scale of the turbulence, and $R$ is the core's radius. Next, we perform AMR simulations of the prestellar collapse of an isothermal, transonic turbulent core at two different resolutions, and a non-turbulent control simulation. We find that the turbulent simulations collapse at the same rate as the non-turbulent one, so that the turbulence generation does not significantly slow down the collapse. We also find that a) the simulations approach near balance between the rates of energy injection from the collapse and of turbulence dissipation; b) $g\approx0.395\pm0.035$, close to the "virial" value (turbulence is $\sim35-40\%$ of non-thermal linewidth); c) the injection scale is $L_d\lesssim R$, and d) the "turbulent pressure" $ρσ_\mathrm{1D}^2$ scales as $\simρ^{1.64}$, an apparently nearly-adiabatic scaling. We propose that this scaling and the nearly virial values of the turbulent velocity dispersion may be reconciled with the non-delayed collapse rate if the turbulence is dissipated as soon as it is generated.
