Star Formation out of the Magnetised Interstellar Medium

磁场是星际介质的一个基本组成部分，它对星际介质在不同空间尺度上的动力学有很大的影响。一个长期存在的问题是它们对星系中恒星形成的影响。与热压相似，如果磁场足够强大，磁场可以防止自引力气体团块的收缩。因此，气体的过密度必须达到磁性超临界，用质量通量比来量化，才能坍缩，随后才能形成恒星。越来越多的证据表明，ism场是相当强的（B bbbb6 μ g），这就产生了一个问题：超临界云核是如何产生的？回答这个问题是这个项目的目标。在这个提议的项目中，我们将测试这个问题的两种可能的答案，即双极扩散（AD）介导的过程，在这个过程中，局部的质量通量增加，以及积聚过程，气体在很远的距离上聚集。因此，我们将详细研究影响ad模型的物理（例如化学和辐射电离过程），我们将通过全球星系模拟自我一致地探索积累过程。

Magnetic fields are an elemental part of the interstellar medium (ISM) which have a large impact on the dynamics of the ISM on various spatial scales. One long-standing issue is their influence on the formation of stars in galaxies. Similarly to thermal pressure, magnetic fields prevent contraction of otherwise self-gravitating gas clumps if they are strong enough. Therefore, gaseous overdensities must be magnetically supercritical, quantified by the mass-to-flux ratio, to collapse and to subsequently allow the formation of stars. There is increasing evidence that the ISM-field is rather strong (B > 6 muG) which gives rise to the question how supercritical cloud cores can be generated? To answer this question is the goal of this project. Within this proposed project we will test the two possible answers to this issue, namely the ambipolar diffusion (AD) mediated process, where locally the mass-to-flux is increased and the accumulation process, where gas is gathered over large distances. Therefore, we will study in detail the physics which impacts the AD-model (e.g. chemical and radiative ionisation processes) and we will self-consistently probe the accumulation process with global galactic simulations.