论文标题
非巨型湍流介质中磁场和气体密度结构之间的相对取向
The relative orientation between the magnetic field and gas density structures in non-gravitating turbulent media
论文作者
论文摘要
磁场是在星际介质中调节结构形成的动态重要药物。研究局部磁场和气体（柱 - ）密度梯度之间的相对方向已成为分析磁场对银河系中密集气体形成的影响的强大工具。在这项研究中，我们对非砂气，等温气体进行数值模拟，其中湍流是螺旋杆驱动或压缩驱动的。我们发现，只有最初具有强磁场的模拟（等离子体 - $β<1 $）才显示出磁场和等值轮廓之间的优先方向的变化，从低密度下的大部分平行到较高密度的垂直线。因此，仅压缩湍流无法诱导观察到的过渡向附近的分子云。在相同的高初始磁化下，我们发现螺线管模式在相对方向上产生的密度比压缩模式增加了。我们进一步研究了相对取向的时间演变，发现它在一个动态时间尺度后的湍流强迫保持不变。
Magnetic fields are a dynamically important agent for regulating structure formation in the interstellar medium. The study of the relative orientation between the local magnetic field and gas (column-) density gradient has become a powerful tool to analyse the magnetic field's impact on the dense gas formation in the Galaxy. In this study, we perform numerical simulations of a non-gravitating, isothermal gas, where the turbulence is driven either solenoidally or compressively. We find that only simulations with an initially strong magnetic field (plasma-$β<1$) show a change in the preferential orientation between the magnetic field and isodensity contours, from mostly parallel at low densities to mostly perpendicular at higher densities. Hence, compressive turbulence alone is not capable of inducing the transition observed towards nearby molecular clouds. At the same high initial magnetisation, we find that solenoidal modes produce a sharper transition in the relative orientation with increasing density than compressive modes. We further study the time evolution of the relative orientation and find that it remains unchanged by the turbulent forcing after one dynamical timescale.
